Generator Ground-Neutral Bonding

Apr 8th, 2013 | By | Category: RV Safety
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When A Portable Generator Won’t Power Your RV

See my video on testing for a floating neutral at https://www.youtube.com/watch?v=M-bTLdMjuqU

I received this email from a reader who wants to power his RV from a Honda portable generator.

I have a 2011 Fleetwood 40-footer. I am trying to get my Honda EU3000 generator to power up the motorhome for a few items. My display after plugging in will show NO LOAD. This generator will power anything else I try such as a 30-foot trailer with one air conditioner, compressor, etc. I also have a Coleman 5000 and that will power up the motorhome. I have an adapter cord 50-amp female going to 30-amp (3 prong) male. The Honda worked with my 2002 Monaco hooking the same way. The reason I like to use the Honda is when I am at the track this time of year, there is no need to run the motorhome generator since there is no need for air conditioning. I have called Honda and they were no help. John Z., (Purcellville, VA)

50AmpACDistributionSystemJohn, all RV electrical systems are wired with their Ground and Neutral buses floated (un-bonded from each other). There’s lots of good reasons for this, most specifically that it’s an NEC and RVIA code requiment that the safety ground wire never carries any load current, and there can be only one Ground-To-Neutral bonding point in any distributed electrical system in the USA. Now, when you’re plugging your RV into power from a building (your garage outlet) or campground (pedestal outlet), your RV has its Ground and Neutral buses “bonded” (connected) together externally as part of the service panel’s earthed safety ground system. Again, lots of reasons for this, but the fact is you can only have a single G-N bonding point according to the National Electrical Code and RVIA building codes.

So when your RV is powered by its on-board generator, this G-N bond connection is created by the transfer switch set to generator mode. But when the transfer switch is set to receive shore power, your RV expects the external power source to bond its Ground and Neutral wires together. Now if you have an inline voltage monitor system from a manufacturer such as TRC or Progressive Industries, your voltage monitor is checking for the Neutral and Ground voltages to be very close to each other, probably within 3 volts or so. This works well if you’re plugged into shore power that’s properly grounded and bonded, but this voltage protector can be tripped off by plugging your RV shore power plug into a portable generator without an internal Ground-Neutral bond. If you don’t have a voltage protection device on your RV, then you may never know that your generator has a floated neutral (un-bonded G-N bus).

Contractor-type generators such as your Coleman 5000 are generally G-N bonded internally, which is why it runs your RV just fine. However, many portable inverter generators from companies such as Yamaha and Honda (your EU3000 specifically) have floated Neutrals (no internal Ground-Neutral Bond) since they expect an external G-N bond to happen somewhere else. And while RV-approved generators may have an internal G-N bond, it seems that many of the most popular portable inverter generators from Honda and Yamaha have floating neutrals.  Now I discussed this very point with Honda engineering , and they confirmed that their inverter generators have floated Neutrals and simply say that you should follow all local electrical codes for bonding-grounding. So your EU3000 isn’t providing the Ground-Neutral Bond that your RV requires to think it’s getting properly grounded power, while your Coleman 5000 has a Ground-Neutral bond already so it operates your RV properly. Seems crazy, but that appears to be the scenario.

N-G Bonding Plug2It’s pretty simple to wire a special “Ground-Neutral Bond” jumper cable for your Honda or Yamaha generator which will allow you to power your RV through its voltage protection device. You can obtain or make a dummy 15 or 20 amp “Edison” plug with the Neutral (white) and Ground (green) screws jump together with a piece of 12 or 14 gauge wire (see photos below). This G-N jumper plug can be plugged into one of the generator’s unused 20-amp outlets, and the entire generator’s electrical system will be N-G bonded. You can then use the other 20-amp Edison outlet or the 30-amp outlet to power the RV.

 

N-G Bonding Plug1Just be sure to mark this plug specifically for its intended purpose. It won’t really hurt anything if it’s plugged into a correctly wired home outlet, but it will create a secondary G-N bonding point that could induce ground loop currents and create hum or buzz in a sound system.

So this is a generator-only G-N bonding plug which should be only plugged into a portable generator while powering your RV.

 

 

Mike Sokol
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250 Comments to “Generator Ground-Neutral Bonding”

  1. Ray says:

    Thanks for the great information Mike. I have a Champion brand inverter generator with the floating neutral. I found out when I got a surge protector and it threw an error code when hooking up the generator. Lucky the surge protector had a bypass switch, but it would be nice to use it’s full functionality so thanks for the Edison plug tip.

    • Mike Sokol says:

      I saw a list somewhere of all major generator brands/models which showed if they had the neutral bonded or floated. If I can find it again I’ll append it to the end of this article.

      Mike Sokol

      • Mike says:

        Here is the list I think you were talking about
        http://www.generlink.com/CompatibleGenerator.pdf

      • Alan says:

        I just read your article about creating a “Edison” plug for Ground-Neutral bonding. The explanation was really clear for a layman like myself.
        My Powerhouse PH2100PRi inverter generator has a floating neutral also, and the manual shows that you “Before connecting any loads, ground the generator with a length of heavy cable, connecting the generator’s grounding terminal to an external ground source”. They show a picture of the cable running to a metal stake pushed into the soil.
        However, if I use my receptacle tester, with the generator running, and grounded as they describe, with no other loads attached, the tester reports “Open Ground”. If I plug in the cord from the fifth wheel trailer and test with the tester, I again get “Open Ground”.
        Is the system safe in this condition, or do I need to prepare the “Edison” plug.

        • Mike Sokol says:

          They’re confusing earth ground with bonding. Portable generators for RVs are NOT required to have an earth ground rod at all by the NEC (National Electrical Code). A ground rod IS NOT the same thing as a neutral-ground bond, which is why you’re still showing an open ground even after hooking to a ground rod. So you should be able to build my $2 G-N bonding plug, and create your single-point G-N bond, which is EXACTLY what the NEC requires. If you can, please write a letter to Powerhouse asking them to contact me. The information they have in their users manual is simply incorrect for use with an RV or any sort of home emergency power situation.

      • kelly says:

        I have a Powerland Tri Fuel 10000 and when connected to my RV via an electrical panel it never idles down. Even if I turn off everything in the RV it always runs at top speed which causes it to use too much propane. Any ideas? I have not installed the floating ground because everything works fine with the exception of the generator.

  2. Ray says:

    Got this off the Champion website FAQ

    “What is “floating neutral” and how does it affect my generator?”

    “Most Champion Power Equipment generators have a “floating neutral”, meaning that the neutral circuit is not connected to the frame or to earth ground. This also means that both legs on the receptacle are hot legs, which is normal for floating neutral generators. As a result, there is no specific hot leg and neutral leg wiring arrangement for the generator winding connection to the receptacle. The floating neutral configuration is common for applications such as connection to a recreational vehicle and connection to home power where the transfer switch does not switch out the neutral to ground connection.

    The floating neutral eliminates the potential of being shocked by contacting a hot leg and the generator frame at the same time, which could occur if an electrical device such as a hand held tool suffered from an internal short circuit.”

    • Mike Sokol says:

      Yes, and that’s why these generator manufacturers “think” their portable generators should have a floated neutral, but IMHO they’re mistaken. If a portable generator is powering your house via a home transfer switch, then the G-N bond is already in the house’s service panel. And if your RV’s on-board generator is powering your RV via it’s own transfer switch, then the G-N bond is created by that transfer switch. But every distributed power system needs to have one (and only one) G-N bonding point as a return path to trip circuit breakers in the event of a short circuit of hot-to-chassis. So when your RV is plugged into shore power, the power pedestal supplies that G-N bond via the safety ground wire back to the campground’s service panel. But if your RV is being powered from a portable generator via your shore power cord, then the transfer switch doesn’t bond the G-N together because it assumes you’re plugging into a already bonded power source. This was done by RVIA code so that plugging your RV into a reversed polarity outlet (swapped Hot and Neutral) wouldn’t cause a hot skin condition. (but they didn’t know about Reverse Polarity Bootleg Ground outlets (RPBG) until I’ve demonstrated that condition and named it).

      That’s why you need to provide your own G-N bond when powered by a “floated” portable generator using your shore power cord. I’ve already confirmed this with the engineering department at Progressive Industries as well as tech support at Honda Generators. Looks like it will take a major NoShockZone campaign with NEC references to get the point across to these generator manufacturers. In the meantime, you just need to build a simple Edison G-N bonding plug to allow your voltage/surge protectors to operate normally.

  3. My 5000 watt Coleman generator (1999 vintage) did NOT have a neutral to ground bond as it came from the factory. The Edison power outlets had the U grounds tied to the generator case, but I found to my horror that the 120/240 volt twist lock outlet had its ground terminal connected to NOTHING!!! Since this generator is used almost exclusively in the field powering sound equipment, I modified it to add a Neutral to Ground bond in the generator, and to properly ground the ground terminal of the twist lock power outlet.

    I too once saw a list of portable generators that showed which models had internal neutral to ground bonds and which did not. If I remember correctly only around 5 or 10% of the models listed had such bonds. Those that provided the bond seemed to be exclusively models sold for running power tools on job sites.

    • Mike Sokol says:

      Yeah, I saw that same list of portable generators a few months ago, and the majority of portable generators appeared to be unbonded. I talked to Honda tech support about this, and they said the reason was that you might hook your generator into your home’s service panel, and since it was already G-N bonded, they didn’t want to create a secondary bond. I asked about including information on a G-N kludge plug (as I’ve indicated in the article) but they said that they can’t comment on that officially, but that all RVs needed to follow “local code”. Of course, but definition” an RV motorhome can be in dozens of “local code areas” every year, so that’s pretty useless advise.

      It seems that the generator manufacturers think that “floating” everything is a answer. And if you’re only running one appliance from a generator, then it sort of makes sense. However, in distributed power systems such as a music stage, this allows one single amplifier on stage with a hot-to-earth short, to AC bias the safety ground of the entire system. I really think that all outside performance stages should comply with standard G-N and earthing codes, which is the only way to guarantee the safety of the performers from electric shock.

      • Douglas says:

        So, tomorrow morning at church we’ll be running our sound system from a Honda EM50is 5000W generator. It uses an inverter, and I’m pretty sure it doesn’t have a GN bond (although I haven’t metered the G-N resistance to check)

        Our question is – should we use the earth stake to ground the case, or should it be left floating? The local production company that provided it didn’t give a solid answer.

        Also, I metered the voltage across the outlets, and it doesn’t look right, compared to what I know it should be http://new.noshockzone.org/rv-electrical-safety-part-iii-–-outlets/
        Hot-neutral was 254V (we’re in Australia, so that’s right), neutral-ground was 10V (this was with some load on other outlets), and hot-ground was ~5V. That hot-ground is what I’m worried about – shouldn’t that also be 254V? Is it different being an inverter generator, rather than mains supply? Does that mean the earth rod isn’t driven in far enough?

        All this stuff gets more confusing the more you try and read about it. Some people say of course you should ground it, and others say it would be more dangerous to ground it!

        It’s tomorrow morning, and I don’t really know what to do…

        • Mike Sokol says:

          It sounds like your strange meter reading is due to the neutral floating, and from what Honda tells me, ALL of their inverter generators have an unbonded neutral. I’m not an expert on Australian wiring, but if it’s the same as the UK (single-leg 240 volts), then it should probably be earth grounded. A ground stake really doesn’t have to be a low-impedance connection to the soil. In the USA a ground rod can have up to 100 ohms impedance and considered to be within code compliance. Without reading Australian code I can’t be sure, but if I was in your situation I would bond the neutral to ground at the generator, then bond the generator frame to the existing ground rod. But you really need to confirm this with an electrician if possible.

          Please report back later on how this worked out as I’m very interested in wiring issues in other parts of the world.

          Mike Sokol

        • Mike Sokol says:

          Douglas,

          How did your generator grounding situation work out?

          Mike Sokol

          • Douglas says:

            Well, the electricity company didn’t end up cutting off our power until later in the day, so we didn’t need the generator at all! (Worth clarifying – no, we don’t have a transfer switch or anything in the building. We just ran ~30m of extension cables to connect thing to the outlets directly on the generator, completely separate from the building’s power supply. So, the generator forms its own completely separate system.)

            So, we never actually started it up again.

            There was no GFCI (RCD, in Australian) on the generator or anything connected to it.

            I measured the resistance across the ground-neutral (while it was off!) to confirm that no, they are definitely not bonded.

            The decision was made that if needed, we would ground it, but not bond the earth to the neutral – as we didn’t really have time to test that, and we should be able to trust the hire company who use it as-is in similar situations all the time.

            I still think that doesn’t sound right, so will follow it up with the hire company and see what they think.

            We also had a second, smaller, ~1kw Yamaha generator we borrowed from someone else. It had a plastic casing, no ground stake, but did have a bonded neutral, and GFCI. My impression is this one is correct and safer. Not grounding it is ok, as long as nothing connected to it is earth grounded? – but that often doesn’t happen, so the generator should be earth grounded anyway.

  4. Les Peacock says:

    Hi Mike!

    This is an issue that I have researched and until I found this page I was pretty lost. The problem I have is with a Yamaha ef4500ise which is hard mounted to the frame of my travel trailer. We have no problems on shore or campground power and all outlets including gfci’s work and test as they would in a normal household situation. When the generator is connected to the trailer things change. This is an inverter generator and I believe it has a floating neutral.

    The problem is that my gfci outlets in the trailer will not stay set when running on generator. They work for a while but then they stop and cannot be reset. The non-gfci outlets work fine. When testing both the 110 outlets on the generator and the functioning non-gfci outlets in the trailer I get some strange readings: Hot-ground 121V, Hot-neutral 84V, ground-neutral 84V.

    So i figured I had a floating neutral and built a plug exactly as you described. I shut down the generator and plugged it into one of the 110 outlets. I started the generator which ran well but the AC light was not lit and I had a lit overload lamp. I shut it down and unplugged the bonding plug. Waited about ten minutes and restarted the generator. It ran well and AC light lit, overload light not lit. Tested power again and have same result as above.

    Having voltage on the ground leg should throw out the gfci right? Any ideas?

    • Mike Sokol says:

      Interestingly, GFCI outlets don’t need or sense the ground wire at all. Shoot me an email with your phone number and let’s discuss. I have an idea what this might be, but need to confirm a few things with you first. My direct email is mike@noshockzone.org

  5. Les Peacock says:

    Hi Mike!

    I am having trouble finding out if my generator test figures are correct. I have a Yamaha inverter generator (ef4500ise) hard mounted to my RV frame. The voltage readings are as follows (this is on the 110 outlets on the generator and the regular non-gfci outlets in the trailer when it is connected via the 30 amp RV power plug to the generator):
    Hot-ground 123V
    Hot-neutral 84V
    Neutral-ground 84V

    When the generator is disconnected and I am on shore power via the same RV power cord in a 30amp receptacle at home the readings on the RV non-gfci outlets I get this:
    Hot-ground 120V
    Hot-neutral 120V
    Ground-neutral 0V

    The problem is that my gfci plugs in the trailer don’t work when the generator is connected. They cannot be reset. Is this a floating neutral? I made up a kludge plug per your instructions and plugged it into the generator. When I started it the motor ran well but I had no AC indicator light and an overload light. I stopped the generator and removed the kludge plug. I waited 10 minutes and restarted the generator and my AC light came back on and the overload light was off. Tested again with meter and got same voltages as above from plugs on generator. Any ideas?

  6. Have new Ryobi 2200 inverter generator with floating neutral. Does anyone know if your neutral-ground bond plug will work with this model inverter generator? It’s output is a duplex receptacle 20 amp, single phase, 120 volt. Is there a way to test the inverter generator to see if it is ok the use the N-G Bond plug? I don’t want to damage a $ 550.00 geny. THANKS

    • Mike Sokol says:

      It should work just fine, and I can’t imagine any way it could harm a generator. Just to be safe I would start up the generator without anything plugged in, then plug in the G-N bonding plug. Then plug in a 3-light outlet tester to see if it looks OK. At that point, remove the 3-light tester and plug in your RV shore power plug. Repeat the 3-light outlet test inside your RV, and if it all works you’re home free. However, if you can have Ryobi contact me, I’ll be glad to discuss this G-N bonding plug with their engineering department at length. Where did you purchase this generator? That’s a start.

      • Home Depot. This generator is to be connected ( plugged) to a Reliance transfer switch that switches neutral that is a sub panel to my service panel at home. So -I assume the neutral to ground bond has to be at the generator. My old generator (bonded neutral) ran everything great thru my transfer switch-old generator was too large in wattage ,heavy, loud and a gas guzzler. Ryobi inverter is better for my needs- mainly gas boiler @ 575 watts. I will try your instructions above. THANKS

        • Mike Sokol says:

          William,

          Actually, your home service panel should already have a Ground-Neutral-Earth bond in place, unless something is very wrong. Generators for emergency backup powering of homes are NOT supposed to be G-N bonded, so as to avoid the double G-N bond that would take place if both the genny and the service panel were G-N bonded. Your transfer switch should not be able to separate your G-N-E bond in your service panel, only disconnect the appropriate loads and separate your generator power from the incoming power line. So I think a non-bonded generator should work fine for powering your home, but need my G-N bonding plug for powering an RV. Let me know if I’m on the right track with this.

  7. mike reidy says:

    So I do NOT need to “earth ground” my generator as long as I use the twist lock plug to the transfer switch because it will ground through the house, correct?

    • Mike Sokol says:

      If you’re talking about connecting a generator to your house service panel via a transfer switch, that’s correct. All house power systems have a ground rod to tie the safety ground to the earth, so a separate earth ground rod for the generator is not required. The same goes for RV generators that only require a Safety Ground to Neutral bonding point, but not an actual Earth Ground Rod to be code compliant.

  8. Tom L says:

    Hi Mike. I want to be able power my home high efficiency gas boiler during a power outage. The boiler has electronic controls and I’m told needs a bonded neutral for the flame sensor. The boiler has a cord and is plugged into a 15 amp receptacle. The plate reads it uses 13 amps. How might I use an inverter type of generator to power just this load? I plan on running 12 or 10 ga ext cord. Length would be like 15 ft. I’m thinking I need a inverter type to get the low THD for the electronics. The manufacturer says the product needs 115 VAC +/- 10% 60hz 1ph and the bonded neutral.

    • Mike Sokol says:

      Actually, a standard constant speed, non-inverter generator has a very low distortion naturally, and that’s how all steam and water powered large scale generators work. But those types of generators have to run at full RPM all the time, so they’re fuel hogs. A suitcase generator such as a Honda EU2000 is an inverter generator with a very low THD inverter output that should easily run your furnace. The advantage is that is can go into eco-throttle mode and save a lot of gasoline while your furnace is calling for much less amperage. But as I’m sure you’ve surmised, those small inverter generators have a floated neutral and could be a problem. I’m pretty sure that my basic G-N bonding plug would properly bond your generator’s neutral and run your furnace. However, you probably need to have your generator on a longer than 15-ft cord to keep it far enough away from your house to avoid potential carbon monoxide poisoning. I’m writing an article on just this subject next week, so that’s why I’m worried that your generator is too close go your house. You should be able to run a 12 gauge extension cord at least 50 feet without significant voltage drop from 13 amperes of current.

  9. Dean H says:

    Hi Mike,

    This article was extremely informative, but I still have a question. I have a new Yamaha EF6300iSDE inverter generator with a floating neutral. It has two GFCI 20A 120V outlets mounted on the generator, along with a 30A 120V twist lock outlet, and a 120/240V four prong twist lock outet. Aside from RV/Trailer use, I would like to use this generator to backfeed my house in case of a power failure. I purchased and installed an interlock kit for my main panel, and installed an L14-30 twist lock power inlet box on the outside of the house.

    The four wires from the inlet box are connected in the house panel as follows: both hot wires to the double backfeed breaker, and the neutral and ground are connected to the grounding block in the panel. When attempting to run the generator in 120/240v mode connected to the power inlet box, the generator’s overload light comes on and it stops producing power. In my troubleshooting, I disconnected the ground wire from the grounding block in the panel, and the generator runs fine.

    Here’s what I do to backfeed my home. I haven’t turned on any circuits yet, as I want to resolve this issue first. (Hope I’m not providing too much info…thought more was better to help other people):

    – Power up Generator in 120/240v mode, and wait five minutes
    – Turn off Main breaker from power company feed
    – Turn off all breakers in the panel
    – Connect generator cord from 120/240V outlet on generator to power inlet box
    – Slide the interlock device up and turn on the generator back feed breaker

    Before turning on the designated circuits and creating a load, the generator’s overload light comes on. However, if I do the same routine with the generator in 120V mode, the overload light does not come on, and the generator runs fine.

    I am going to create a N-G plug as you suggested, and give it a try. Just wanted to run my situation by you to see if you had any other suggestions or information. I must say that your article was the best at describing the Neutral Ground bonding issue. Any other info would be appreciated. Many thanks!

    Dean

    • Mike Sokol says:

      I’ve seen this exact problem with another EF6300iSDE generator. In that case I had the reader use a 100-ohm resistor instead of a solid jumper wire. I believe that worked for him, but it’s been a while since that email. Since I don’t have a 6KW Yamaha generator to experiment on, I don’t know the exact reason for it shutting down with a solid G-N bond, but I’m guessing the fact that it has a 120/240 split phase output introduces additional load protecting circuitry.

      Yamaha and Honda customer support, are you listening out there? If so, contact me about doing some G-N bonding experiments on your generators and I’ll be glad to write an extended article about it.

      Mike Sokol
      mike@noshockzone.org

      • Dean H says:

        Mike,

        Thanks for the quick reply. Regarding the 100 ohm resistor, it appears that they come in different wattages, such as 2w, 3w, 5w, 10w, etc. Should I use any one in particular?

        Thanks again!

  10. Mike Sokol says:

    I just ran the math again, and I must have recommended a 1,000 ohm resistor since a 100 ohm resistor could need to dissipate 144 watts under a worse case scenario. With a 1,000 ohm resistor, you could get away with a 10 ohm resistor. But I just don’t like this solution too much.

    As I think about this more, I think that perhaps a pair of reversed silicon diodes in parallel that would provide a 1/2 volt float could satisfy the generator’s trip circuitry. Something like a pair of these 25-amp stud diodes could be the best solution: http://www.ebay.com/itm/25A-1000V-BLOCKING-DIODE-WIND-GENERATOR-SOLAR-PANEL-25-AMP-PANELS-TURBINE-STUD-A-/111173549109?pt=LH_DefaultDomain_0&hash=item19e275bc35

    But let me think about this a bit before anyone builds one. Again, I could use a little support from Honda and Yamaha on this topic, but their customer service departments are of little help.

  11. Dean H says:

    Mike,

    I spoke with Yamaha customer service/product support yesterday, and they were of little help. They did tell me that on the EF6300iSDE, the neutral is bonded, and not floating. This is contrary to what I’ve been reading on some sites and forums. I then asked how to un-bond the neutral, and they would not give any info.

    So it looks like I have to figure out a way to either un-bond it, or install something that would switch the neutral. Any ideas?

    Thanks,
    Dean

    • Mike Sokol says:

      I think they’re confused and that your neutral is floating. Here’s how to test for it. With the generator off, use a digital voltmeter to check the resistance (ohms) between the neutral and ground contacts in the output receptacle. If it reads as being very close to zero ohms (under a few tenths of an ohm at most) then it is indeed bonded. But if it reads hundreds or thousands of ohms, then it’s certainly floating. A second test is to power up the generator and plug in a simple 3-light outlet tester to the 20-amp receptacle. If it shows an open ground, then it most certainly has a floating neutral.

      This is exactly the same sort of confusion I’ve heard from Honda about their inverter generators. I’ve tried to get both manufacturers to fund some consumer articles written by me on the subject, but so far my requests have been ignored.

      After you perform the above tests, contact me to determine how you should proceed.

      • Dean H says:

        Hi Mike,

        Even further clarification from Yamaha on 12/3/13…

        I spoke with a manager about my neutral bonding question for the EF6300. He said that the first version that was made in all of 2008 had a bonded neutral. After 2008, all EF6300’s have a floating neutral.

        I told him of my situation with connecting the 6300 to my house via and interlock kit with a two pole breaker in my panel, and NOT using a transfer switch. He said that if I ground the generator to the house grounding rod, I should have no issues. Any thoughts?

        Thanks,
        Dean

        • Mike Sokol says:

          Dean,

          Yes, bonding the generator frame to the house grounding rod is the correct thing to do. I believe your generator has a lug on the side for just such grounding. However, if you have a Ground-to-Neutral-to-Earth bond at the input panel, then your generator’s frame is already connected to earth ground. But there’s no harm in having a second generator frame to ground rod connection.

  12. Cub 800 says:

    I also am having a problem with my generator running my furnace in my house. I have an older Coleman 5000 w generator with two 120 receptacles one L5-30 receptacle and a 120V / 240 v receptacle.
    I modified my furnace with a receptacle/ plug on the power line so I could unplug from the power coming from the panel box and plug into the generator. My generator probably has a floating ground also.
    my question is since I will only be using the adapter from my extension cord to the furnace could I bond the neutral and ground inside the adapter and label it as such? that is instead of using a separate plug just to bond the two?

  13. Cub 800 says:

    OK, I have just made the above mention modification to my adapter cord, The LED indicators on the plug I used now show green. also the furnace starts and runs the same as if it were on house current.
    I am considering moving the bonding wire to the L5-30 plug that goes into the generator, any problem with leaving the wire in the furnace adapter in place? would there be a problem with having two points where the N/G are bonded?

  14. Cub 800 says:

    Thanks, after typing my last message I went back and reread the string and saw where it said only one bonding point.
    I moved the bonding wire to the L5-30 plug going into the generator, its a short adapter and would give me more options. If I want the generator N/G bonded I simply put in this plug and all the receptacles on the generator are bonded. if I don’t want that I simply remove this modified ( and clearly marked ) plug and the generator returns to a floating ground.
    After much research the info I found here was the easiest to understand and follow.
    I ran the furnace on generator power for a couple hours yesterday as a test, every thing ran fine.

    Thanks again.

  15. Mark W says:

    while trying to remember a webpage i ran across about this subject, I stumbled across your page again on the same subject. however shortly (?) after reading all this and the comments, I discovered the webpage I was looking for (which I still actually had bookmarked, but neglected to search my bookmarks 1st). it does actually give a fairly in-depth explanation as to why it is good (or why not) to have a floating neutral on a generator. ( unless it’s equipped with a GFI ).

    http://members.rennlist.org/warren/gt5000c.html

    however after reading all this information ( and about 15 other pages on the subject of what N-G bonding is. ) and having electrical knowledge and hopes to someday get licensed myself. I have come to the conclusion that #1 OSHA requires generators to be bonded! #2 travel trailers, RVs and boats require it, in most cases. #3 it is required “not to be” with the home electrical system as a backup source of energy. #4 I have completely forgotten why I was looking this up, although I think it has something to do with inverters. #5 if I were at some point to own and operate a generator i will most likely install a switch to remove the issue of possible loss of bonding plug/immediate OSHA compliance and don’t forget versatility.
    when I was doing some Electrical work as an assistant, I remember running a extension cord from one house to the other and into the panel before the overhead service was installed and turned on. looking back on that I would’ve created a double bonding over the extension cord. so I have learned that if I were to do it again it would probably be a good idea to leave the bonding screw out until services was turned on and the extension cord be nolonger needed for temporary use.

  16. Donald Robinson says:

    How will the adapter work when running two of the inverter generators in Parallel?

    • Mike Sokol says:

      I’ve had several readers use the G-N bonding plug on Paralleled Honda generators. One was done using an aftermarket parallel kit, while a few of them had one of the Honda companion generators which doesn’t require an external kit. These all worked well, with the only slight exception being the external parallel kit version when the interconnecting “parallel” cables were accidentally phase reversed. That phase only caused a 3-light tester to indicated H-N swap on the outlets in the RV, but otherwise worked. So I recommend that you use the G-N bonding plug on the “second” generator feeding your shore power plug, plus make sure you plainly mark the parallel interconnecting cables so it’s clearly visible how they plug into the generators. Apparently those parallel interconnect cables only have a small colored stripe to indicate the connection which is easy to get mixed up.

  17. John says:

    Thanks for this post Mike. Saved my butt getting my furnace fired up from my generator.

  18. John Ambrosino says:

    Hi, I have an older Generac Portable generator 7550exl. I have it hooked up using the 30 amp twist lock on the generator to an inlet box attached to the house which is wired (10/3) to my main elec panel. I use an interlock system UL listed. The generator has a floating neutral which is what is needed since my elec panel is bonded neutral. I want to buy another portable generator but cannot find one with a floating neutral. Looking for at least a 7500 running unit. I will also like to know how to remove the jumper wire which makes it a bonded neutral and turn it into a floating neutral. I was looking at the Troy-Bilt # 030477 7000 running/10500surge. how can I identify the jumper wire inside the control panel that makes it a bonded neutral?

    Thanks, John

    • Mike Sokol says:

      John,
      I downloaded the schematics for the Troy-Bilt generator you mention, but there’s not enough info to know if there’s a simple way to un-bond the neutral. But that’s really what should be done to power your home, as you already know. I’ll send an email to Troy-Bilt tech support this week and see if they can offer any info on if the bonding strap can be removed to “float” the neutral.

      • John Ambrosino says:

        Hi Mike, Really, thank you for going out of your way for me. Just an FYI. I did call Troy/Briggs and the girl on the phone did say after some pleading that it can be UNBONDED she didn’t say how. I don’t know if it’s easy or not maybe you can find out.
        Funny thing Troy is saying it’s bonded, and when I downloaded the manual from the internet it said it’s bonded, but when I went onto Lowes web site looked up the model 030477 & looked at the specs it states OSHA Required GFCI outlets it says NO. Again, thank you. I am one of those people that likes to get to the bottom of an issue and your help is great.

        John

        • Carl says:

          I’ve done some work on portable generators and most of the non-inverter units have a jumper behind one of the panel outlets. If you open one up, look should be able to identify it and remove it to unbond the G-N.

      • John Ambrosino says:

        Hi Mike, Can you tell me if my 2003 Generac 7550exl is a grounded neutral or a floating netural? I thought it was a floating neutral, but Briggs and Stratton tech said it’s a bonded neutral. I have it hooked up from my generator 120/240 to my inlet box (which is grounded), to my electrical panel using an interlock system. It has been working fine no problems but if it’s true that the generator is bonded and the panel is bonded how is it working? and is it running safely? If I need to remove the jumper wire to make it floating neutral do I also need to extend the green wire which coming off the mother board and now connected to a nut which grounds it and bring it over to the neutral side of the 120 outlet that I just removed the jumper wire from in-order for the idle control to work?
        Thanks, John

        • Mike Sokol says:

          John,

          So here’s my thoughts on using a G-N bonded generator to feed a service panel that ALSO has a bonded G-N connection. While the NEC specifically prohibits G-N double-bonding, and I agree that double-bonding a home or business sub-panel will cause all sorts of ground-loop effects (hum and buzz in sound systems), I don’t think there’s any harm or real danger caused by using a portable generator that’s ALREADY G-N bonded to feed a home service panel that’s ALSO bonded. That’s because the possible neutral-ground intermingled currents are quite small with respect to the normal currents that are available. For instance, Even a 6,000 watt generator with a split-phase 120-120 (240-volt) output will have a maximum of around 30 amps current. And that’s the worse case condition with a completely unbalanced output. I know that the NEC worries about these currents showing up in the chassis of the generator, and potentially creating heating problems. But even assuming a max of 30-amps neutral current that would split to 15-amps when combined with the safety ground wire, those 15-amps should not be enough to cause any real heating problems or damage to the generator itself. Now, if you’ve got a serious generator like we use for rock shows (50 KW or more), then there’s a LOT of neutral currents running around (think 200 amps at times) which can seriously overheat secondary G-N bonding paths.

          That being said, while its specifically a code violation to do so, I suspect there many thousands (or more) G-N bonded portable generators hooked into G-N bonded home service panels at this very moment, and I’ve never heard a single report of any safety issues or generator damage cause by this practice. So while I can’t specifically endorse this practice since it’s a code violation, I don’t think it’s a problem when used with small (under 10 KW or so) generators. Still, I would love to get some feedback from manufacturers on this issue. And if any of them would be generous enough to send me one of their products for experimentation, I would be glad to set up a demonstration and measure all currents under these G-N double bonding conditions.

          • John Ambrosino says:

            Hi Mike, Thank you for your input. GREAT KNOWLEDGE. I want to double check. My Generac is a 7550 running watts and a 13500 surge. In you evaluation you stated (under 6000 watts) you found little to no problems running a bonded neutral portable generator to a bonded neutral electrical panel with this small of a unit correct? I just want to reiterate that my unit is 7550 running/13500 surge. So we are still good? I am using a UL listed interlock system in the panel. I did find out where and how to remove the bond on the duplex outlet of my unit, very easy. I believe since it’s simply to remove I should just go a head and remove it. It would be safer overall Do you agree? Also my inlet box I remember has a green ground as well so are we bonded in 3 places? How does that work?

            Thanks Again, John

          • Mike Sokol says:

            If you DO have a simple way to un-bond the G-N connection in your generator making it a floating neutral, then you SHOULD remove the bonding strap. That way you’re completely in compliance with the NEC (National Electrical Code). If you were to use this “floated neutral” generator on an RV, then you’ll need to re-install the G-N bonding strap. Or you could just use my G-N bonding plug if need be. My previous note was for all those generator owners who CAN’T float the neutral. I always recommend following the NEC, even though sometimes it doesn’t make a lot of sense. However, generator G-N bonding is one of those things I would like to see changed since there’s a LOT of confusion about this.

  19. Orlando says:

    Hi Mike,

    This is a great post with very valuable information. I need some help. I just purchased a new Honda Eu3000is (Canadian model) that has a floating neutral. I have checked the voltage output at the generator and I have found 63 volts on the (neutral) to ground and 64 volts on the (hot) to ground connection on the receptacle. Across the neutral and hot from the generator I have 127 volts.

    I wanted to hook up a transfer switch in my main house panel. The 6 circuit transfer switch does not break the neutral. It only breaks the loads. I am afraid of attaching this to my main panel. I know the main panel has a Bonded neutral. The transfer switch has a ground and neutral wire that requires attachment to the main panel neutral and ground connections. I have read over the internet that connecting this generator to this configuration will blow the inverter. I tried contacting Honda and they referred me to the dealer who also did not have an answer. What is your opinion? Can this be done?

    I also tried connecting the generator to my furnace that has a circuit board by using an extension cord. The furnace will not start in heating at all. Once I put generator power to the furnace plug that I attached to the furnace, I get an error code that states Reverse Polarity. I believe this is due to the furnace not liking the power on the generator neutral side. I know this is also due to a floating neutral. Can I use the NG bond plug to correct this problem? I am just worried I am going to damage the generator. If I am using the NG bond plug can I still plug other appliances into the generator at the same time?

    Regards Orlando

    • Mike Sokol says:

      You really don’t have a problem. Since your Honda EU3000is has a floating neutral, it’s just a matter of understanding when you need to add your own G-N bond. The main point to remember is that your should always have ONE and ONLY ONE point of Ground-Neutral bonding. As delivered your Honda generator has NONE, which is fine for running portable tools such as a drill.

      So here’s your first scenario. If you’re connecting it to the house service panel via a transfer switch, the house service panel will provide the G-N bond along with a ground-rod connection. I call this a G-N-E bond and it’s supposed to be done on EVERY incoming service panel. Since your house panel provides the G-N bond, then you don’t need (or want) a G-N bond on your generator. So connecting the floating generator directly to your transfer switch is just fine and the neutral should now measure 0-volts to ground and 120-volts to hot.

      In the second scenario of connecting it directly to your furnace with an extension cord, you have the opposite condition. Your generator doesn’t have a G-N bond and your furnace power supply doesn’t have a G-N bond either. So you need to provide ONE G-N bond which is as simple as using the G-N bonding plug illustrated in this article. Just plug the G-N bonding plug into one of your generator outlets, and plug your extension cord into the other generator outlet. You should then measure the correct 0-volts from neutral to ground and 120-volts from neutral to hot. You can also plug in any other appliances to your generator with the bonding plug in place.

      As far as damage to your generator, I’ve had dozens (maybe hundreds) of readers use my little bonding plug without any problems. Modern inverter-generators are very smart, so if they don’t like a load they simply shut down without damaging themselves. And Honda tech support has told me (off the record, of course) that it should be fine. But try using the G-N bonding plug first and measure your generator outlet with both a 3-light cube tester as well as a voltmeter. I’ll bet everything will work perfectly using a G-N plug for running a single appliance such as a furnace, or not using a G-N plug for feeding the transfer switch feeding your home service panel. BTW: What brand/model transfer switch are you using and can you email me a picture of the installation?

      Please report back here with what you find out.

      • Orlando says:

        Hi Mike,

        I just wanted to say thanks for your great help on my questions. I started my Honda EU3000 today and plugged in a 3 light circuit tester. The circuit tester showed an open ground. I made a GN Bond plug and plugged it into one of my receptacles on the generator. I then reconnected the 3 light tester and it now shows “correct”. I used a multi-meter and found 127 volts between neutral and the hot leg. From neutral to ground I have 0 volts and hot to ground is 127 volts. This is the same power arrangement as my house. I plugged in an extension cord and wired it into my furnace with the hot, neutral and ground wiring. I also plugged in my hot water tank which is gas fired but uses an Hot surface ignitor to ignite the fuel and they both worked flawlessly. This is without grounding my generator grounding stud. I now have heat when the power goes out.

        Can I make the GN Bond at the end of my extension cord instead of back at the generator? The end of the extension cord consists of a 2 X 4 metal box with a receptacle plug. I would be making the GN Bond right at the receptacle screw terminals and then plugging right into the metal box receptacle. I would think this would be the same as making it back at the generator, but I would have to use this extension cord for the generator only and not for other uses.

        Can I use a jumper wire to the generator ground stud to one of my metal electrical boxes as a ground or should I install a grounding rod? Do I really need to ground the generator stud?

        My transfer switch is an older Generac Model 1276. I have not installed it yet but I will definitely send you some pictures of the install once the weather gets warmer.

        Thanks again

        • Mike Sokol says:

          Excellent. You can see this a very simple solution to what appears to be a complicated problem. Once you understand the “One G-N Bond” principal, it’s all logical.

          As far as an extension cord with a G-N bond at the end, in theory that would work fine. However, as you note it can ONLY be used as a generator extension cord. So if your generator has a unique twist-lock output plug, then that would be a practical solution. If not, then you should very carefully mark that extension cord for generator use only. People get confused, and plugging it into your house power would create a code violation by double bonding your house G-N.

          For grounding there’s no need to connect a jumper from the generator to your house ground because you’re ALREADY grounded. That’s right, the chassis of your generator is connected to the safety ground wire in the generator’s power outlets. That in turn is connected to your house ground rod via the ground wire in the extension cord. Since your hot-water heater and furnace are grounded via both wiring as well as plumbing, then your generator chassis should be grounded as well. To be sure, just meter between the frame of the generator and your service panel chassis. If it’s less than 1 volt, then you’re good to go. If it measures more than a few volts, then something else strange is going on, so contact me before adding your ground-chassis jumper wire.

          • Orlando says:

            Mike, I got around to hooking up my Honda EU3000is to my main house electrical panel. I just hooked it up temporarily with the transfer switch and I did not use the GN bond plug since my house panel is bonded. I tested it with the 3 light cube tester and it showed “correct”. I put a few lights and a unit heater threw the transfer panel on only one circuit and I ran it for 15 mins. Everything looked great.

            Is there any long term harm with bonding these Honda inverter generators? Not sure why so many people say that bonding inverters will make them go up in smoke??

            I will send you some pictures of my final transfer switch install, hopefully in a couple weeks.

            Thanks Again

  20. John Ambrosino says:

    Sorry Mike, I didn’t read your evaluation correctly you mentioned under 10kw, not 6kw. So my Generac 7550 running watt should be fine. I still believe it would be safer to remove the jumper. Do you agree?

    Thanks, John

    • Mike Sokol says:

      Yes, if you CAN unbond the Neutral by removing the jumper, that’s the best way to do it.

      • John Ambrosino says:

        Mike, thank you so very much, I noticed after reading some of your other evaluations for other people You mentioned back in April of 2013 you knew of a website which advised you which generator is bonded or floating. I believe that company is called Globel Power Products. Generlink Compatible Generator Guide. I’m sure you already found it, but if not I hoped this helped. I am looking at Costco which sells the Champion 41532 and the Westingtonhouse 7000ec portable units as a back up to my unit. Any thoughts on either or, or none. the Champion is already a floating neutral the Westinghouse can be removed very easy.

        Thanks, John

  21. Jack Lyons says:

    Mike,
    I have a Honda2000i generator that I have used for several years to power my 5th wheel through an IOTA 50A Generator Transfer Switch. I have recently decided that when powering the RV with the generator I want to go through my hardwired TRC 50A SurgeGuard Model 34560 (older model purchased and installed Nov 2009).

    Here is what I have done. I picked up a plug and bonded the neutral and ground together so that I could run my generator through the hardwired SurgeGuard. So the other day I decided to try out my new plug. Just for grins I decided to start the generator and plug the RV in without the bonded plug plugged into the generator. Much to my surprise start up looked normal on the SurgeGuard with LINE 1&2 lit steady and DELAY flashing. After the 2 min 16 sec delay built into the SurgeGuard, power was supplied to the RV and the indicator lights on the SurgeGuard were normal (no faults indicated LINE 1&2 illuminated steady).

    Next, I got out my receptacle tester and checked all of the outlets inside and outside on the RV while running on generator power. They all indicated “CORRECT” and no “OPEN GROUND” or other fault condition. Also I checked that all of the outlets on the GFCI circuits would trip the GFCI outlet when the “TEST” button was pressed on the tester, which they did. Next, I plugged the receptacle tester into the generator with the RV still powered from the generator and got a “CORRECT” indication (no “OPEN GROUND”).

    I unplugged the RV from the generator and immediately got an “OPEN GROUND” on the tester still plugged into the generator.

    So then I plugged my bonded plug into the generator and got a “CORRECT” indication on the tester which told me the generator and bonded plug were doing what I expected.

    Then I decided to create a couple other conditions. First, I plugged my bonded plug into the generator and then plugged the RV into the generator. Again, normal indications on the SurgeGuard (LINE 1 &2 illuminated and DELAY flashing for 2 min and 16 sec then power applied to the RV, LINE 1&2 lit steady). Again all outlets inside and outside read “CORRECT” and all of the outlets on the GFCI circuits would trip the GFCI outlet when the “TEST” button was pressed on the tester.

    Next, I unplugged the RV and bonded plug from the generator and plugged my tester into the generator and it reads “OPEN GROUND”. Then with the tester still plugged into the generator, I plug the RV into the generator and this time on the SurgeGuard LINE 1&2 are illuminated, DELAY is flashing, but this time the CAUTION light on the Surge Guard is illuminated steady (there is nothing in the SurgeGuard “Indicator Light Status” table for this condition). This time after the 2 min 16 sec delay, power is applied to the RV, the CAUTION light on the SurgeGuard goes out and the tester that is plugged into the generator now indicates “CORRECT” and all outlets inside and outside the RV again test “CORRECT” and all of the outlets on the GFCI circuits would trip the GFCI outlet when the “TEST” button was pressed on the tester.

    In reading the owner’s manual again and again it doesn’t appear that this SurgeGuard will protect against an OPEN GROUND condition. The manual states “CAUTION LIGHT (POLARITY PROTECTION) Indicates possible MIS-WIRING or Current to Ground condition. (Will prevent power on 50Amp unit ONLY).” I know it will protect against over/under voltage because it has kicked power off to the RV before when these conditions were detected.

    So my underlying questions are: Should I be concerned that I can run on generator power without the bonding plug installed? Just to be on the safe side should I always use the bonding plug? Or should I not run the RV through the SurgeGuard from the generator at all?

    All of the outlets inside and outside indicate they are wired correctly when shore power is applied from my home or any other pedestal and also when I run the generator directly to the transfer switch by passing the SurgeGuard.

    Thanks in advance for any light you can shed on this .

    Jack

    • Mike Sokol says:

      Jack,

      Here’s what I think is happening. Your RV wiring itself has enough conductivity between the neutral and ground bus’s to create an RV G-N bonding situation. Now there’s several things that could be doing this, two that could be very bad, and the other not so bad.

      First: It’s possible that inside your RV’s circuit breaker panel or shore power plug there’s actually been a G-N bond installed at some time in the past. Perhaps it was a DIY thing, or done by a misguided RV technician. In any case, your RV’s Neutral and Ground bus connections MUST remain isolated from each other internally, so that needs to be corrected immediately.

      Or Second: You could have a white neutral wire somewhere in your wiring harness “shorted” to the RV chassis. This could be by a screw in the wall, wire with rubbed off insulation, or even a failed appliance such as a microwave transformer. Again, that needs to be identified and corrected since it can cause serious problems if you plug into a campground pedestal with reversed H-N polarity.

      Or Third: I could be that there’s some high-resistance leakage between an RV electronic’s or appliance’s neutral and chassis. Not really low enough resistance to be considered actual “bonding” but something that could go rogue at any time. With your RV disconnected from all power, measure the resistance between the ground and neutral contacts of the shore power plug. If it’s many thousands of ohms, then you have high-resistance leakage. If it’s hundreds of ohms down to a few ohms, then you likely have a pinched wire somewhere. If it’s less than one ohm, then someone improperly bonded your neutral and ground together inside your RV’s circuit breaker panel or shore power cable.

      But I would ALWAYS add the G-N bonding plug to your Honda EU2000i generator when it’s powering your RV. And there should be no need for the G-N bonding plug any other time such as running power tools. Please let me know what you find out.

      • Jack Lyons says:

        Mike,
        Thanks for the rapid response. I am not able to do the testing you have recommended until next week. I will let you know what I find when I am able to check things out.

        Jack

      • Jack Lyons says:

        Mike,
        I was able to do some testing on the rig today. Here is what I found out. First I unplugged the rig from shore power and read the ground and neutral on the cord from the RV. The reading was 00.0. With the rig still unplugged, I started reading the ground and neutral for each of the outlets inside and outside the rig.

        All of the outlets that are daisy chained onto a GFCI outlet read 00.3 as well as the GFCI outlets themselves. All the other outlets in the rig read 00.0 except for one circuit I found where the reading was 00.7.

        I determined that on this circuit are two outlets and two 110v light fixtures. One of the outlets is on the back wall of the 5th wheel while the other outlet and two light fixtures are in a slide out. I did shut the circuit breaker for this circuit and still got the 00.7 reading telling me there must be a bond in the wiring (nail or screw through the neutral wire) after the circuit breaker for this circuit. Is my thinking correct on this?

        I started doing some troubleshooting and am pretty confident I have eliminated the wiring for the two lights and the outlet in the slide. By pulling one of the light fixtures down and disconnecting the wiring, I removed power from both lights and the outlet. After doing this, when I read the ground and neutral on the fixtures and outlet all read 00.0. The ground and neutral wires that come from the outlet in the back and into the slide where power is picked up for the slide fixtures and outlet still reads 00.7.

        I ran out of time today, but will continue working my way back to the circuit breaker panel soon. My next step will be to remove the wiring from the back outlet that runs to the slide and see what my readings are in the slide. If the slide now reads 00.0 then I would guess the problem is in the wring somewhere between the breaker panel and the back outlet. If my logic is flawed on what I am doing, please let me know.

        Is it possible I have a bad outlet on the back wall? I guess I can check that when I pull the one out in the back.

        Also, even with the circuit breaker OFF for that circuit, I could still get the rig to accept power from the generator without the bonding plug. But to be clear, when I was took all of the ohm readings 110vac power was removed. I did not disconnect the battery.

        Thanks in advance,
        Jack

        • Mike Sokol says:

          Jack,

          If you are indeed reading 0.00 ohms between the Neutral and Ground contacts of your shore power cord, any other reading is not needed. It should be reading many THOUSANDS of ohms, not a fraction of 1 ohm. The fact that you’re reading a dead short implies that there’s a definite Neutral to chassis bond/short, perhaps in your RV’s circuit breaker panel itself. So that’s the first thing to figure out. And there’s a strong possibility that this short is in your transfer switch since I think you had that replaced. But trust me, this is a very serious mis-wiring error which is a violation for both the NEC and the RVIA codes. And the fact that it works properly using a floated neutral generator tells you it’s in violation (and dangerous) when plugged into any pedestal or home outlet/receptacle. Something is very wrong here… Shoot me your phone number to mike@noshockzone.org to confer with me directly.

  22. Jack Lyons says:

    Mike,
    After talking with you on the phone last week, I did the test with the DC light tester to see if I had a Neutral to Ground bond somewhere in the rig. With ALL shore power removed, I connected one end of my tester to the POS side of the battery and probed the Neutral slot on one of my electrical outlets. Nothing, not even a faint light. Then I probed the Ground of the electrical outlet and very bright light on the tester. So this tells me I DO NOT have a neutral-Ground bond inside the rig.

    So, after talking with you and doing this test, I think I should be okay to run the generator using the bonded plug as you described?

    Jack

    • Mike Sokol says:

      Jack,

      That sounds correct. You’re looking for an open-circuit between the RV chassis and the Neutral contact (no bulb lighting), and a short-circuit between the RV chassis and the Ground contact of the outlet (bright light). So yes, adding the G-N bonding plug should be safe and offer continued operation of your surge/voltage protector. Great job troubleshooting the problem.

  23. jerome says:

    Hello,
    I need some guidance or advice.

    I would like to run my plasma cutter (hyper therm 45 single phase 220 ) off my generator ( Coleman Power-mate PM0496504.17) Floating neutral on the generator.

    I have a lot of scrap metal in the woods that needs to be cut into smaller pieces so I can move them.
    My questions are.

    1) Do I need to drive a ground rod into the ground and ground the generator to it ?

    2) Do I also use the G-N bond plug ?

    3) Just use a 110 volt sawzall instead.(Not a great option)

    The Plasma cutter has two hot legs and ground only.
    I really need to be careful not to fry the plasma cutter (very expensive).
    Thank you for your guidance .

  24. Alan Tigner says:

    I don’t have an RV but do have a boat that has this problem. I have a Xantrex MS2000 inverter that was wired to have sub-panel containing all 120V outlets and a few other low wattage (<2KW) devices (microwave, coffeemaker, etc.). The inverter is powered by four 6V golf cart batts (wired to output 12V). The rest of the boat's AC is either powered by the shore side service or an 8KW diesel generator. When either of those sources is present the inverter senses it and switches to external AC and begins to charge the inverter battery bank. When away from the dock my plan was to connect a small portable generator that I could run during the day to charge up the inverter batteries versus running the main generator 3-4 hours a day to maintain the charge. Last season (summer in the Great Lakes) I tried a friends Yamaha 1000 portable which he used on his boat to charge his main batteries and was successful in doing so. When I tried it my inverter sensed a reverse polarity and would not accept the incoming voltage. After reading this article it seems that the plug you created for the bonding might do the trick. Am I correct?

    • Mike Sokol says:

      Yes, that sounds correct. Those little Honda generators have a floating neutral which your inverter think is reverse polarity or an open ground. The G-N bonding plug should do the trick. Please report back after you try it out.

      • Alan Tigner says:

        Thanks for the info. I’ll know in about a week.

      • Alan Tigner says:

        The G-N bonding plug worked perfectly. We are now on our boat for the next two months and hopefully the new Honda 2000 will reduce the hours I have been putting on the onboard genny just to keep the inverter bank charged. Thanks again for the answer.

  25. richard says:

    Could I just use the ground input on my Honda generator and attach a grounding rod kit?

    • Mike Sokol says:

      No, a ground rod really doesn’t provide a “ground”. You need to bond the neutral of the generator back to its own frame, and the frame of your RV. That’s the only way to provide a safe path for fault currents to go.

  26. Adam Hunter says:

    Hi Mike,

    Thanks for your invaluable input on common RV electrical issues.

    I have a new fifth wheel protected by a built-in surge protector with open ground protection. Am I correct in understanding that if I create a “N-G Bond” on a Edison plug then the whole generator is now grounded including the 3 prong 30 Amp plug that I would use to supply the RV?

    When I called Yamaha about this issue on my new 3000iseb inverter generator they seemed “reluctant” to comment on my plan. Lack of manufacturer support is frustrating to say the least……

    Can you comment please.

    Sincerely
    Adam Hunter
    St. George. Ontario
    Canada

    • Mike Sokol says:

      Yes, you only need a single bond created by the jumpered Edison plug, and every outlet on your generator plus your RV’s electrical system will all be properly Neutral bonded. That’s how it’s supposed to work, but Honda and Yamaha won’t discuss this information with consumers. One thing to note is that some of the 6,500 watt 120-240 volt inverter generators from Honda (at least) appear to need their neutral floated for proper operation. I haven’t researched exactly why they do that since a 6,500 watt generator would be useful to power a home via a transfer switch in the panel, and all homes are G-N bonded in their service panel. More to experiment with.

      • Adam Hunter says:

        Thank you very much for the confirmation. I will go ahead and make the plug.

        Thanks Adam

      • Adam Hunter says:

        Mike,

        Further to our conversation about generator wiring;

        I am planning a 30 amp 3 wire extension from the generator to a “factory prep” generator box in my fifth wheel trailer. The trailer generator prep uses 50 amp 4 wire.

        My question is in addition to standard neutral and ground connections to supply the coach with 30 amp generator power would I join the red and black wires from the 50 amp generator prep wire and in turn mate them to the black wire in the 30 amp extension line?
        Is that the right method to carry 30 amp power through a 50 amp cord?
        Adam

        • Mike Sokol says:

          So if you’re connecting to a generator prep box, there must already be a transfer switch in place. If so, that should already do a G-N bond when in “Generator” position. If so, then you do not need a G-N bonding plug. And the transfer switch is where the two hot legs feeding the RV should be bonded to the single hot leg from the generator. But someone will need to study the transfer switch schematics to know for sure how to connect this together.

    • Mike Sokol says:

      Adam,

      Yes, a single bonding point is all that’s required for the entire RV shore power supply. So a simple N-G bonded Edison plug will properly bond everything. And I have talked to both Honda and Yamaha customer service many times, and they refuse to officially comment on this application, but will confirm “off the record” that it should work. Please send a letter to Yamaha customer service and include my No~Shock~Zone info since I would really like Yamaha support to include how to hook up their generators in my NSZ Clinics. It makes more impact if enough consumers ask about something compared to just me talking to them.

  27. john goulding says:

    Wow – Read everyone of these and I am even more confused. Here is my issue and I am going to try and make the scenario simple. I am new to having a coach with 50amp service and a hardwired in inverter. I am trying to use 2 external hondas EU2000i running in parallel to power the coach. Immediately upon plugging in the coach, the generators start to rev high and rev up and down. I can also here what sounds like a door opening and closing (I assume this is the transfer switch). Now I should be at 4000w with this parallel set up and should handle most any power issues in the coach. I did go inside and shut off the water heater which calmed the generators a little, but still reving high and fluctuating high and low. Then I turned on the AC and that made the generators really fluctuate and eventually overload the xfer switch really opening and closing. So I shut all that down quickly. So now I am baffled and upset that there are no directions on any of this stuff!!! So then I repowered up the generators and plugged in the coach again, and this time I turned the inverter disconnect off. The generators calmed way down and seemed to regulate. So here is my questions: 1. Are the external geneators acting like this because I do not have the GN boded plug? 2. When you run external generators to power a coach do you have to disconnect the inverter? 3. Do I still need the GN bonded plug regardless?

    • Mike Sokol says:

      John,

      How are you running your Honda generators in parallel? Do you have a companion or an external parallel combiner? Remember this setup will only make 120-volts (not 240-volts) so you’ll still need a 30-amp to 50-amp adapter to plug from the generator combiners to the shore power plug of your RV. It will split the single 30-amp/120-volt outlet to the two hot legs in your RV’s circuit breaker panel. So you won’t have 240-volts going into your RV, which is just fine since everything is 120-volts anyways. This will allow you to run combined loads of 30-amps which works out to 3,600 watts.

      Yes, you’ll really want to add a G-N bond in the final (companion) generator if you have any sort of EMS (Electrical Monitoring System) and not connected through a generator transfer switch. And no, you should not have to disconnect the inverter when running from generators. Also be aware that these generators will throttle up and down when in “eco” mode. So it’s normal for them the rev up when the air conditioner kicks in and go back to idle when the air conditioner cuts out.

      Sadly I don’t know enough about your exact setup because I can’t get Honda to loan me a pair of EU2000 generators to experiment on. They know exactly what I’m doing on No~ShockZone, and I’ve answered some of their in-house questions about RV hookups and generator bonding. But Honda marketing says they can’t afford to loan me even one EU2000 generator to carry on my RV power experiments. If any of you want me to figure more of this out this type of hookup, please contact your local Honda dealer and show them this thread. Then have them ask Honda directly to support this blog. There’s only so far I can go with theory, and I can’t afford to buy every gadget I need to experiment on. With a pair of EU2000 generators I could run some serious experiments and document how this all works in real world hookups like you have.

  28. […] I found an article online discussing why certain generators didn’t work to power up RVs (http://new.noshockzone.org/generator-ground-neutral-bonding/) and it actually made a bunch of sense.  One key point: “..an NEC and RVIA code requirement […]

    • john goulding says:

      Thanks Mike,

      Just did a week in Mammoth and used the two generators in Parrallel. I have the EU2000 STd and the companion so I can use the 30a receptacle. I started with just the Std on the 20a but i noticed when its running and nothing is on in the coach it runs quiet and then ramps up like its about to overload and then goes back to quiet. It does shut off all the inverter controlled circuits (the ones TV’s are plugged into etc.), Microwave does not shut off. I notice all this happens when batteries are charging, When batteries are full it seems to stabilize. When I connected to the companion same thing, however stabilized quicker. Too bad there are no instructions for the inverter that came with the coach. I did download from mfg. but do not have technical expertise to undertsnad all. I think I just need to make the jumper referenced in the article and that should resolve my issues. Thanks for clarification and
      assistance.

      • Mike Sokol says:

        John, from studying the basic schematics how how these EU2000 generators work I can predict that the G-N bonding plug should go into the 20-amp outlet on the “Companion” generator. That’s because the linking cables are non-polarized and using the std EU2000 for the G-N bonding point could invert the Hot and Neutral on the 30-amp twist lock outlet. Not a big deal really, since that by itself should not cause a hot-skin condition or damage anything. But it would cause any kind of EMS protection system to shut down power to your RV.

        As far as the generators “ramping up” their throttle(s), that because your battery charging system is drawing more than the small amount of “eco mode” current the generator puts out at idle speed. So see if your inverter/charger has a lower charging mode. But even if it doesn’t these likely nothing wrong your generator(s) since it’s doing exactly what it was designed to do… idle the engine for low power consumption, then rev up the engine when you need more wattage. It’s smart enough not to hurt itself even though it’s a bit strange to hear it rev up without anything obvious happening in your RV except for battery charging.

  29. Steve says:

    I have an EMS on a boat theat when running my yamaha ef1000 inverter gen the systems runs great (underpowered so it stays at full RPM until batteries are charged and cant run ice maker ect.) I now have a Honda EU2000 inverter gen now my Heart Interface 1800 EMS blinks with error of reverse polarity. I would guess to go with the bonded N-G plug your post suggests but hope this will have no serious effect on my EMS. I have already built the plug and cable just a little scared lol. Thank you for the wisdom you share.

    • Mike Sokol says:

      Steve,
      Yes, I think that your EMS is interpreting the floating neutral on your EMS as reversed polarity. I would first plug the G-N bonding plug into your generator while it’s not connected to anything else, then start it up and check outlet polarity using a simple 3-light outlet tester. If that checks OK (which it will if you’ve wired the G-N bonding plug correctly), then plug your boat shore power line into it and check the EMS for proper polarity indication. Again, if your wiring is correct on the boat’s EMS, then all should be well. Finally, check every outlet on your boat with the 3-light tester to confirm that each of them is wired properly. You really need to start upstream as far as possible and begin testing the generator alone, then check the EMS, and finally verify that all outlets are wired properly. Assume nothing.

  30. Walter Pelley says:

    Good Day,

    I am a Electrical contractor and enjoyed very much your comments on Neutral bonding. I have installed many generator panels over the last few years and have one quick question for you. I usually use a 30 amp Seimens panel with a 3-pole breaker. This panel allows you to use a generator with the neutral either bonded or non-bonded. It seems that it is perfectly find to use an un-bonded Honda 3000 watt inverter generator if you do not switch the neutral and bond it directly to the neutral bus in the generator panel. However if the generator has a N/G bond you must use the third breaker provided to ensure that the house and generator neutrals are switched and isolated when transferred (eliminating a possible second G/N point). Local inspection authorities accept this setup. They say it is perfectly fine to use a non-bonded or floating Neutral generator as long as the neutral is bonded to the neutral bar in the panel and Not Switched. I have been doing this for some time with no Problem, am I doing this correctly?? Thanks again for your valuable information on this not so well understood topic.
    Walt

  31. Mike says:

    Question to Mike Sokol:
    Mike,
    I have a concession business and trailer. I was powering the trailer with a Duromax 8,000/10,000W genset. It quit.
    I recently ordered a Champion 7500/9500 genset. Both have 50amp receptacles, which is needed to power my trailer. Trailer has a 60amp service panel and about 14 15amp breakers in it.
    My question is regarding the floating neutral. I don’t know if the Duromax had it but it looks like the Champion does.
    I park in paved parking lots, concrete etc. I cant drive a ground rod into these areas and wonder if there is an alternative?
    At home, I plug the trailer into a 110 GFI outlet to power my freezers. Before doing so, I have to remove the ground screw in the panel that bonds the ground and neutral together or I trip the outlet. While using the Duromax, I would replace that screw and never had an issue. Reading this about the G/N bond and floating neutral on the Champion, causes me concern.
    Should I cancel my order? After using the Duromax for only 90 days and having it fail, I wanted to go to another brand. Finding a 50amp genset under 1200.00 is difficult at best.
    Any advise would be appreciated.

    Mike

    • Mike Sokol says:

      Don’t confuse G-N bonding with actual earth grounding. Since a portable generator is isolated from the earth, you don’t need a ground rod driven into the dirt for a localized power system such as used to power the typical concession trailer or RV. However, you really DO want a G-N bond since that’s what allows the circuit breakers to trip in the event that a hot wire is shorted to the frame somehow. The basic rule of bonding is that there should be one ONE Ground-to-Neutral connection, and that should be external of the RV’s service panel. The RV or concession trailer itself must have NO G-N bond on its own. So an RV with an on-board generator will have the G-N bond established by the transfer switch. If you plug into a pedestal, that pedestal will include a G-N bond from back at the service entrance panel. However, when you plug into a portable generator, you need to provide a G-N bond somehow. There’s no rules as to when a generator has a G-N bond or not, but typically if it has a GFCI, then it DOES have a G-N bond. If it doesn’t have a GFCI, then it DOES NOT have a G-N bond. If it DOESN’T have a G-N bond, then you can simply add one with a ground plug as I’ve discussed above. If it DOES already have a G-N bond, then just plug it into your concession trailer and go. You can confirm the G-N bond using a simple 3-light outlet tester making sure the two yellow/amber lights are on, and not the red light. If you get an open ground indication, then you have an unbonded Neutral or broken ground wire somewhere in your power chain. Let me know if this answers your question.

      • Mike says:

        Mike,
        Thank you for the quick reply. The new Champion genset 7500/9500 mod 41534 has a floating neutral.
        Reading your post, indicates that I should create a plug, bonding the neutral to the ground? Correct?
        If I am always using the 50amp receptacle, will this also be bonded if I use the bonding plug in the 110 receptacle?
        Question three would be, do I remove the grounding screw in the panel, inside the trailer when using a GN bond at the genset?

        I’m not an electrician, but have played too much with electricity. I can’t afford a customer getting burned or worse.
        Please let me know your opinion and thanks again,

        Mike Uher

        • Mike Sokol says:

          Yes, you should create the bonding plug for your Champion generator. And yes, plugging it into the 20-amp/120-volt receptacle will also bond the 50-amp receptacle. As far as the grounding screw in your trailer’s panel, it’s a code violation (and dangerous) to EVER have the neutral bonded to ground inside the trailer itself. The G-N bond must be external, either by a generator transfer switch, a bonded portable generator (my G-N Edison plu), or by the shore power plug (which gets its G-N bond from the service panel). A double-bonded G-N connection allows neutral currents to flow in the EGC (Equipment Grounding Conductor – more commonly called the safety ground) which is a code violation. The EGC is only there for ground fault currents, nothing else.

          • Mike says:

            Mike,
            Thanks for the response.
            I will be leaving the ground bonding screw out and creating the NG plug as you described.

            I leave the screw out at home anyway, because it trips the GFI outlet my water pump is plugged into, while Im connected to my garage via a circuit with another GFI in the garage.
            Funny part of this, a friend and electrician foreman, told me to leave the green ground screw in the panel, when running off generator. He felt it better to bond the two. I see your point, that it would be better bonded at the source.

            Thanks again
            Mike

  32. Gordy VG says:

    Hi Mike,

    Very informative site… I just purchased a Voltmaster XCR105 9,500 watt Portable generator to replace my 12 Year old Generac Storm Chaser 5500 Watt portable Generator. Initially when I had my 2002 residence setup, I had a gentran transfer switch setup with a 30 amp inlet. I had since had an electrician remove the transfer switch and run the generator cord directly into my service panel with a interlock on it. Much better setup for me w/o having to flip many switches on the transfer switch.

    Upon my disappointment when I came home and tried a trial run using my 30 amp inlet box and starting the Voltmaster XCR105, I immediately began getting a trip on the GFI on the main panel which is full GFI protected.

    Upon reading a lot of these comments, I am guessing because the XCR105 is full GFI protected and the Neutral Bonded to Frame, that’s causing the issue. Does this sound correct? I saw in a few comments that going back to a transfer switch will eliminate this. I would like to keep my setup I have now with the interlock panel on my electrical panel.

    Any information on the Voltmaster generator’s for changing the Neutral Bonded to Frame?

    Thanks in advance.

    Gordy

    • Mike Sokol says:

      Gordy,
      According to the National Electrical Code, you can have only ONE G-N bonding point in any distribution system. Since your house service panel already has one that can’t be disconnected, then your generator needs to have its Neutral floating to avoid neutral currents showing up in the EGC (safety ground) circuit. That current is probably what’s unbalancing your GFCI circuit and causing it to trip. You need to identify how to unbond the neutral and ground at your generator. I am a bit surprised that your generator has a GFCI on a 30-amp circuit breaker feeding a 4-wire 240-volt twist-lock plug. Or am I missing something?

      • Gordy VG says:

        Thanks Mike for quick response. Yes the full panel 120, 30 and 50 amp outlets are all GFI protected. Do you have any schematics for the Volt masters to make floating neutral?

        Thanks in advance.

        Gordy

        • Mike Sokol says:

          No, I don’t have any schematics for you generator. Please contact the manufacturer and have them contact me if there’s any questions about what you’re trying to do. They should be really interested in this application.

          • Gordy VG says:

            Thanks Mike,

            I sent an email to Voltmaster at the same time I sent you one. I will let you know what they say. I wanted a heavy duty portable generator for home use and did not realize the headache this neutral bond issue would cause. I just want to be able to use my interlock panel with this setup as I did with my smaller generator that I have used this way for the past 10 years.

            Thanks in advance.

            Gordy

  33. Steve B says:

    I’m going to be using a DuroMax XP4400EH generator for emergency power only. It will feed a totally isolated and dedicated 4 outlet box inside the house. Again, NOTHING is tied back into the house electrical system.

    I see that most peoples questions are involving the use of a transfer switch, but I’m still not clear on whether I need a grounding rod and wire for my situation.

    I see from the chart that this generator has a floating neutral, so my question is, do I still need to run a ground wire to it?

    Thanks in advance for your help!

    • Mike Sokol says:

      Remember, there should be ONE and ONLY ONE Ground-Neutral bonding point in any power distro system. So since you have an isolated outlet box, your generator SHOULD have a G-N bond in place. Also, even though it’s not specifically required by code, I feel that any generator feeding multiple power drops (which I assume you’ll be doing from your 4-outlet box) SHOULD have an 8-ft ground rod connected (bonded) to the generator’s GROUND terminal, which I’m sure it has. This emulates exactly how the existing power distro system in your house works. In addition, your extension cords should probably have GFCI protection on the outlets (NOT at the generator) to protect you from accidental shocks between hot and earth.

  34. Gordy VG says:

    Mike,

    Ok, so here is the deal with the new Voltmaster XCR105 genset I purchased. I recontacted the dealer, they indicated a “Were Sorry” it should have been prepped with the genset Neutral Bonded to Frame to a “Floating Neutral” like the Honda’s. I just dropped the genset off and when I pick it up, the Neutral will have been switched from bonded to frame to floating. With this setup, I should be able to plug into my inlet box which is attached to my main panel by an interlock w/o tripping the GFI’s on the genset. Again, this will be 99.9 % used only for emergency home power if the power goes out.

    Now, IF, for whatever reason I would need to take the genset to a remote site for portable power with it being setup with the floating neutral ground, my question is will using the $2 G-N bonding plug make the genset alright to use on a remote site or skip the $2 G-N bonding plug and use a grounding rod and the grounding lug on the genset?

    Thanks again in advance for your assistance. Very informative site.

    Gordy

    • Mike Sokol says:

      If you’re using your generator stand-alone at a remote site, you generally don’t need a ground rod, unless you’re distributing to multiple locations. But you really should add the G-N bonding plug to keep your neutral and ground at the same potential, which was the original intent of the G-N bond that came with your generator. The $2 Edison plug with the G-N connection does exactly the same thing.

  35. Ranger and Jin says:

    I have a Boily 3000 inverter generator that trips when I plug the RV into to the 30 amp plug. The manufacture sys it’s a ground fault and I can”t find one. Do you think the Edison plug would solve my problem?

    • Mike Sokol says:

      There’s something different about how the Boily inverter generators are wired. IIRC on a Boily inverter gen the hot wire measures 60 volts to the ground, and the neutral wire measures 60 volts to the ground. So together they make 120 volts. If your RV has its neutral and ground properly isolated, then this should work. But it can’t power an RV with a built-in EMS (Electrical Management System) Such as a Progressive Industries EMS/Surge-Guard since it will assume you have an open ground and shut down. So no, I don’t think a bonding plug would do any good for you. If you like, please have the manufacturer contact me and I’ll discuss this issue with them. While the Boily generators are very inexpensive, they might not be the best choice for powering an RV with an EMS. But I’ll reserve my judgement until the manufacturer confers with me.

      • Ranger and Jin says:

        No surge guard in use with the Boily Generato online. The best I can do is to give oyu the contact phone for their distributor. The Power shack and BottomLine Trading (512) 902-3397. The guys name is Tim or Jim I forget.. He seems to be very knowledgeable about the Boily and I have heard of no complaints from other users.

        Let e add this because it may be relevant. When at a friends house last summer and I plugged my rig into his a 30a GFCI protected line. The GFCI went offline. I tried another GFCI and same issue. I wasn’t able to get my RV up until I removed the GFCI and put a regular 30A RV plug in. Since that seemed to be an issue I have tried to find a potential problem in my RV wiih no joy. Hope the added info helps since Boily says the gen should run my RV and I’ve have not heard of anyone else with the same or similar problem

        • Mike Sokol says:

          Your symptoms suggest that the Neutral and Ground wires inside your RV are improperly bonded together. You should be able to measure near infinity ohms when measuring between the ground and neutral blades of your shore power connection with a DMM (disconnected from any AC power source, of course). If you do measure continuity, then start looking for a wire shorting to the chassis. And you need to confirm that there’s no neutral to ground bonding screw installed in your RV’s breaker panel.

  36. Walter T says:

    Great Work Mike Sokol:

    As a weekend warrior involved in many projects to save a buck, I can say without doubt that you are providing info that generator manufacturers and sellers have not made clear. You are saving lives and medical expenses and connecting the dots so that we have a better understanding of wiring for generators.

    Thank you for your sacrifice,

    Walter T
    Passaic NJ

  37. mike deibert says:

    I have a Champion 4000watt gen. It has 120v 30amp recept. I have a transfer switch un switched neutral! Volt testing I’m getting 60volts pos. and neutral sides! Floating neutral. If I plug the Generator into my bonded transfer switch will I have 120volts to my panel? Any advice? Thanks Mike

    • Mike Sokol says:

      Yes, I believe that the Champion generators all have a true floating neutral. So try the G-N jumper plug first on the generator by itself, power it up and measure to see if you have 120-volts from Neutral to Hot and use a 3-light tester to confirm polarity. If that much works properly then it should be safe to plug in your RV shore power.

  38. mike deibert says:

    Thanks for the fast response! I’m trying to use the Gen set to power a home with a 120v transfer switch!
    The 30 amp RV outlet has 60volts on pos. pole and 60 volts on neg. poll! If I use 2 wires to the transfer panel will I still have 30amps? At 120 volts on the pos pole? Is this normal?

    Trying to be safe
    Best Regards Michael

  39. Mike Sokol says:

    Yes, that’s exactly how it works. But remember that you don’t need an G-N bonding plug on your generator when connected to your house system via the transfer switch since your home’s electrical system supplies the G-N bond. But you can use a G-N bonding plug on your generator to power an RV since it needs to have an internally isolated neutral.

  40. Damon P says:

    I have a B&S 10kw pro series portable generator model # 30556. This has GFCI protected plugs and is nutural bonded to frame. Im trying to run this in to main breaker box useing an interlock kit. All is wired correctly as I had a friend who’s a master electrican of 30 years install and test. We get power to the main panel but as soon as load is transferred, the GFCI on generator trips. I believe I need to make this a floating ground but B&S will not tell me how. Any help would be greatly appreciated!

    • Mike Sokol says:

      Are you using the 20-amp outlets to feed your interlocked breaker? If so, as you have surmised you cannot have both the generator and service entrance neutral bonded without tripping the GFCI. I did a quick look at http://www.apelectric.com/Briggs-30556-10000W-Portable-Generator-p/30556.htm and this generator also has a 50-amp/240-volt outlet that’s not GFCI protected. If that’s the case, then you should be using that receptacle to power your house. Or am I missing something?

      Please have Briggs & Stratton customer service contact me if you have any questions. There may not be a simple way to unbond the neutral on this generator, and you certainly CAN NOT unbond the neutral in the service for your house. But I may have a simple workaround for this once I draw out the schematic and study it a bit.

  41. Damon P says:

    Thanks Mike for the quck reply! I’m useing the 50amp plug–its on its own gfci breaker so I may be stuck gor now? I’ll call B&S today and see what they say. If I can’t make headway ill have them content you–haw do you lije to be contacted?

    Thanks again!

  42. Damon P says:

    Waited for 25min on hold but finally got to B&S customer service. Unfortunately, no help. Said they couldn’t tell me how to ubound the nutural. They did give me a number to a local repair shop the could tell me how??? Guess they don’t want to help. Haven’t called yet as I was at work and lunch was over after waiting on hold :-/ I’ll let you know how I make out tomorrow.

    • Mike Sokol says:

      So here’s a fix that should work, but I have to consider code issues. You can get a transfer switch in your house service panel that will automatically break the G-N bond in your panel use the generator’s G-N bond instead. However, I assume you’re using a circuit breaker lock-out. If that’s the case, then you don’t have a way to automatically make and break that connection in your panel. So you should be able to simply disconnect the generator’s ground wire where it enters your home service panel. Of course you still need the neutral, and while this sounds dangerous your generator is actually still earth grounded via its own G-N bonding point. But this lifted ground will eliminate the unbalanced neutral currents causing the GFCI to trip.

      But I want you to promise me you’ll get a licensed electrician to do this hookup, and have him contact me about potential local code violations. Shoot me an email at mike@noshockzone.org and I’ll send you my cell number for discussion.

  43. Damon P says:

    This makes sense. I’ll email you for phone #, if issues come up. I live in York ME if that helps with code. My friend is a licensed electrican of 20 years though I’m sure he isn’t up on every code. This sounds safe as the G-N is still established via the generator. One question is will the GFCI still trip if a short is detected?

    • Mike Sokol says:

      Yes, the GFCI will trip if there’s a hot-to-earth fault with more than 6 mA leakage. But the GFCI circuit doesn’t trip for a conventional “short” since that’s the job of the OCPD (Over Current Protection Device) what’s commonly called a “circuit breaker”. In this case that’s your 20, 30 or 50 amp breakers.

  44. Justin clark says:

    Hello,

    I have a slightly different , yet related Generator/Shore Power question. I have an Onan 10kw Diesel Generator hooked to a Kraus & Naimer C42 Manual Transfer Switch (Gen/OFF/OFF/Shore) for Shore/Gen power to an enclosed Telco equipment shelter (including Coleman Mack AC, florescent lights, fan, 8 non-GFCI outlets). All of which are mounted on a trailer. The exterior shore power connector plate is a L14-30P (4 curved blades). I would like to be able to power at least part of the interior (fan, lights, outlets?) by using a simple standard 5-15P household plug under some circumstances, yet be able to retain use of the Generator.

    To that end, I bought the proper L14-30R turnlock connector, 15′ of 10/4 wire, and a lighted 5-15P. When I connected everything (red wire capped at 5-15P end), I got nothing. I figured I would only get one leg “Hot”. However, I noticed that I was immediately popping the GFCI outlet that I was using as my “source”. Changing to a non-GFCI outlet allowed me to connect everything, but when I turned on the breakers and switches for the lights and fan, still nothing. Thinking that I had the wrong leg, I switched the 5-15p from the black wire to the red wire. Again, Nothing.

    I assume I was popping the GFCI, because of the neutral and ground being bonded together at the generator. I assumed that the transfer switch was isolating the ground, but upon further inspection I noticed that the ground was common from Gen side, to shore side, to wall panel / breaker box…

    So question is, is there a way that I can easily power the 120v stuff in the shelter using the above mentioned items from a standard household wall plate?

    • Mike Sokol says:

      I’ve seen a number of trailers like this that had their circuit breaker panel Neutral-Ground bonded by the builders. That’s incorrect for a lot of reasons, one of which is that it will trip an GFCI you plug into. As far as not seeing voltage from your kludge cable, you need to get someone to diagnose this with a DMM (Digital Multi Meter). If you’re not qualified to work on live circuits, then PLEASE get an electrician or RV tech to help you with testing. While the general public thinks that 120-volts isn’t dangerous, in fact it’s potentially deadly under the right circumstances. So be safe and don’t test live circuits by yourself.

      I should also not that you can take a single hot leg from your incoming power and jump it to both L1 and L2 legs on your twist lock plugs. RVers do this regularly, and it works up to amperage capacity of your supply outlet. Just be sure to use a heavy enough extension cord to power this, especially if it’s a long run. So a 12 gauge minimum size extension cord that’s rated for 20 amps is recommended for this.

  45. Mike B says:

    Hi Mike,

    I appreciate the knowledge that you bring to this site and have an interest in ground neutral bonding and the Edison plug discussed in your article. I have two 3.5kw solar arrays powering a 48 volt off grid solar system. I have 32 six volt Rolls S600 batteries (4 banks of 8 batteries) which help me overnight. I also own a 5500 watt Bosch diesel generator. My wife owns a 2014 Chevy Volt. Initially we charged the volt using the 120volt charger made by Voltec. That would take almost 12 hours so I decided to install a Bosch level 2 charging system which does the job in under 4 hours. We are very pleased with the faster charge. I wanted to know if I could still charge the car (using the 120v Voltec) in the event of a grid failure. Normally, when you plug the charge chord into the grid you get a red light first which quickly turns green meaning the charge cord is ready to charge the car. However, when I plugged it into the generator, the red light never turned green. The same thing happened when I plugged it into my “Made in China” 2500/5000 watt pure sine wave inverter connected to battery banks. I asked around for advice and was told that the Chinese inverter was the problem. I was advised to purchase an Outback 3600watt48volt off grid inverter ($1800) since that is a real quality item that will power “any” appliance. I finally got it installed yesterday and have the same problem. The red light on the Voltec will not turn green. The Outback had a nice external ground lug which I connected to the ground bar in my breaker box with a #8 wire. I did some readings using a multimeter and noticed the following. Hot to neutral = 119.5, neutral to ground = zero, hot to ground =65.6. On another forum a member suggested that I may have a ground neutral bonding issue. I would be interested to hear your opinion. Would an Edison plug solve my problem? I want to stress that I would only want to charge off my solar system in the event of a grid failure and understand that this is not an efficient way of charging. I also understand that it could only be done on a very sunny day when my panels were producing maximum wattage. Thanks.

    • Mike Sokol says:

      It does sound like your inverter needs to have its neutral bonded to ground, but I’m going to contact Outback to be sure. However, your voltage measurements just don’t add up. Probably because it’s floating around, but I’ll ask tech support about this. I suspect that this inverter is rated to power a house service panel directly, and that’s certainly G-N bonded. But because of the amount of wattage/amperage available, you’ll probably want a higher amperage bond than a 20-amp edison plug will provide. This is an interesting problem which has far reaching implications, so Outback should be curious.

  46. John P says:

    Hi Mike,

    I believe my questions may have been answered by reading preceding comments but I just want to double check on what I have read vs. what I am doing. In the event of a power failure I have a Champion 4000 which will be plugged into an inlet box outside that is wired to a separate 6 breaker load center inside. The load center will be independent from the existing house wiring and main panel. I will run a few receptacles off of it to plug in to when the power goes out. Rather than using an “Edison plug” at the generator, is it acceptable to bond neutral and ground in the load center? I most likely would be running several lights/furnace off of the outlets so I’m guessing I should ground the generator to earth as well. If so, rather than driving a separate rod for the generator outside can I bond the ground bar in the load center to a nearby source such as the water line lateral which happens to also be the ground source for my main panel?

    • Mike Sokol says:

      Yes, in this case you should bond the neutral and ground in your load center. And you should also include an 8 ft ground rod bonded to this same G-N connection point. Or instead of a ground rod your local code should allow you to use the same water line as your main panel for earth grounding.

  47. Steve L says:

    Hi Mike:
    I have a Durostar DS4000S Generator which I believe has a floating neutral. My setup is almost the same as John P in that I have a load center with three breakers and three outlets, ( that are not connected to any existing wiring or the house panel) that I intend to use for the boiler pump a freezer and a sump pump. The neutral and ground are bonded in the load center. The problem is that I have a lamp with a push button switch that has some type of fault test that has a red and green light that are labeled ok and fault. When I plug this lamp into any of the outlets the lamp goes out and the red fault light comes on. All of the outlets are wired correctly. What do you think the problem could be? Also should I connect the generator gnd lug to a gnd rod?

    • Mike Sokol says:

      Are you sure that the outlets are wired correctly? That is, have a checked them with a standard 3-light outlet tester? It could be as simple as a polarity reversal in the outlets with the Hot and Neutral swapped. So double-check that the black wire is on the brass screw and the white wire is on the white screw. Also, does this lamp work OK when plugged into your house outlets? Perhaps it has a problem. Lastly, while it’s not specifically required by code since this is a portable generator, since your load center is permanent it would be far safer to drive an 8-ft ground rod and connect it to your load center’s G-N bonding point with some #6 or #8 wire. This is mostly for lightning strike protection, but will also protect you from a short-to-ground in one piece of gear elevating the generator’s chassis voltage above earth potential.

      • Steve L says:

        Thanks for the info.
        I have checked all my wiring three times. So I decided to check the lamp information and discovered the fault lights pertain to amount of wattage drawn by the fixture and if the lights come on to put in smaller wattage bulbs. I should have done this first. Why the generator makes it show fault I dont know, maybe not clean enough power, but any way that is now not a problem I guess. Another couple of questions for you. Since the generator is going to be the only source of power for this load center is it ok to connect a ground directly to the generator ground lug from a ground rod instead of back to the load center? Also if I use this generator for my RV should I use a G-N bonding plug? My guess is yes but I would rather know from an expert. Thanks for all your help.

        • Mike Sokol says:

          Yes, you can bond a ground rod directly to the generator’s ground lug. And yes, you’ll probably need to add a G-N bonding plug when using the generator to power your RV.

  48. Nelson Wright says:

    First, thank you for an excellent and informative discussion on generators / neutral / bonding, etc. I found this to be very good stuff!
    Next, for your information and for any Canadian readers, contrary to what has been mentioned here and elsewhere, the Honda EU7000is generators sold up here in Saskatchewan have “neutral bonded to frame” – p. 18 of owners manual; and on faceplate of control panel immediately below the 30A 120/240 twist lock receptacle. The unit I purchased this past week has frame serial number EEJD – 1011XXX
    Above, several have mentioned a list showing which generators have floating or bonded neutrals. That list available on the Generlink website, and shows which generators they consider to be suitable for use with their Generlink automatic transfer switch which gets mounted behind the residence’s meter. (i.e. – meter is pulled off socket, Generlink unit is “plugged in”, then meter is plugged into Generlink unit, then, when standby power is required, the generator is connected to transfer switch with a “Generlink” cord set.
    On that list, Generlink lists the Honda EU7000is as “compatible” with their system, as well as many, many other bonded neutral type generators.
    Now, confusingly enough, from the Generac website – http://www.generlink.com/generators_main.cfm – it states, “NOTE: Per the National Electric Code, all generators must have a “floating neutral ” when used with the GenerLink Automatic Transfer Switch. Please refer to the generator operation manual for bonded neutral specifications.”
    You might see my confusion – the EU7000is is listed as “compatible”, yet has a bonded neutral. Technically, the NEC is a US code and therefore does not apply here in Canada, but I am familiar enough with the Canadian Electrical Code (CEC) to know that the system neutral may attached to ground in only one place.
    It appears that the Generlink unit only switches the hot legs of the generator supply. It has a fixed connection of the cord set neutral (which Generlink refers to as neutral / ground, so I am presuming the cord set ground wires simply attached to the metal case of the switch) to the neutral in the meter base. The concentric neutral underground service cable from my meter socket, into my house panel, consists of only the two hot legs and the neutral (no ground), where the neutral is connected to ground. So, with the generator sitting on dry garage floor, on it’s rubber wheels and plastic legs, does the “neutral attached to the frame” in the generator actually create a second neutral to ground connection? It strikes me that the generator frame is now connected to to ground through neutral, (and therefore bonded in the same manner as the meter socket box) and neither the frame nor the “ground wire” in the cord set are attached to ground.

    • Mike Sokol says:

      Nelson,
      So now you see the industry confusion. I’ve talked to several transfer switch manufacturers and they all note that bonded generators will work with their products even if it is code violation. Some of these transfer switches have an extra contact and actually split the Ground and Neutral bus in the house service panel when using a bonded generator. Or you can simply disconnect the EGC/grounding conductor on the connection between the transfer switch and generator. That still is electrically safe since the generator frame is now “locally” bonded to its neutral. And this generator frame/neutral is bonded to your house ground/neutral which is bonded to your ground rod’s earthing connection. So all will be well and code compliant, at least for the USA.

      Let me know if that explanation makes sense.

      • Nelson Wright says:

        “Only one neutral connection point to ground” – I went for a walk in neighbourhood yesterday looking at utility transformer connections. There is a ground cable going up each transformer pole that connects to the lightening arrester, one side of the high voltage, to the neutral of the low voltage and to the lower wire of the two wire overhead distribution system. Out here, each utility transformer powers two homes; lots are 80 wide, so the lower line is connected to ground every 160 feet throughout the development. So starting from my service panel (when the neutral is connected to ground via #6 wire to two ground rods as per Canadian code), going upstream, about 45 feet of neutral conductor run, that same neutral is attached to ground up the utility pole at the transformer, then following the neighbour’s overhead service conductors about 60 feet of conductor run, the same “neutral” is again connected to ground at his main service. So, in my immediate area, upstream of my own service panel neutral to ground connection, there are four more neutral connections to ground – up the utility pole, at neighbours residential service, and on each next transformer pole both up and down the street, all of these within 200 feet of conductor run from my service.
        So, I am now completely lost as to what is the hazard of multiple connections between neutral and ground upstream of the service panel (I do get it for downstream of the main disconnect) – it seems to me if there is a hazard, I am living dead centre in the middle of it!

  49. C. Smith says:

    I have a small Yamaha ef2000is portable generator (with two 120v 20a outlets, gas-powered, 2000 watts peak) that I will be using to charge our AGM batteries on a solar powered completely off-grid house (i.e. no grid tie at all!) after multiple cloudy days. The generator will be connected to the “AC In/Gen” connection point on a Magnum Mini Panel/Magnum Inverter pre-wired power center (48v Inverter, MS-PAE4448).

    Since this is an off-grid installation and there is no grid-tie with a utility, the Magnum Mini Panel/Magnum Inverter will have a single Neutral-to-Ground bond already (actually one for AC and one for DC), and will be grounded to a ground rod located in the vicinity of the power center. After reading your article, it looks like my Yamaha ef2000is inverter generator has a floating neutral, correct? So, given that, do I need to do the Edison plug (i.e. bonding neutral to ground in the plug) in this off-grid setup with the Magnum Mini Panel/Magnum Inverter?

    Since the generator only has 20 amp “outlet-style” plugs on it for AC connection purposes, I’m going to use an appropriate gauge extension cord, retrofitted with two male ends, to make this connection between the generator and an outdoor-style plug so I can do the ‘plug and play’ style of connecting the generator, given that it’s portable. This outdoor style plug would be hardwired to the “AC In/Gen In” part of the MMP/Inverter power center.

    And in regards to the outdoor style plug, can that be GFCI and still accept power into, rather than out of? I keep seeing that the newer GFCI’s require power to outlet to function, but in this off-grid usage, since the outdoor-style outlet would be on the “AC In/Gen In”, I don’t think it will be receiving power from the MMP/Inverter? Thoughts on this?

    • Mike Sokol says:

      Lot’s of things wrong with your plan. First of all, it’s NEVER OK to make a male-to-male extension cord adapter for this sort of connection. While it can be made to work electrically, someone pulling out the hot end could be electrocuted. So it’s not only a code violation, it could probably get your insurance voided and turn into a lawsuit. So you need a real generator input plug (male) with the appropriate transfer switch. Secondly, you can’t back-feed power through a GFCI since it’s ability to trip will be compromised. Again, this is a big code violation that could leave you liable if something went wrong. In answer to your question about the Yamaha generator, you are correct that the 2000is series does have a floating neutral. So depending on how your transfer switch is wired, it may require a G-N bonding plug as I illustrate. I’m not sure that the Magnum inverter has a bonded Neutral input, so you’ll have to confirm that.

      • C. Smith says:

        Thanks Mike, I appreciate it!

        I’ll be sure to use the appropriate generator input plug (male) and an appropriate transfer switch! Also, I figured the GFCI back-feeding thing was a no-no, so thank you for confirming that for me.

        FYI, the MMP (Magnum Mini Panel), which is connected to the Magnum Inverter, acts as sort of the main panel in this case and will be set such that the AC In neutral is bonded to grounded (i.e. has a N-to-G bond).

        Thus, given my generator (Yamaha ef2000is) and the fact that the off-grid Magnum Inverter that I’m connecting it to will have its “AC In/Gen” Neutral-to-Ground bond made in the MMP, it is NOT necessary to use the Edison N-G plug that you illustrate in your article, correct?

        • C. Smith says:

          I wanted to update everyone and let you know what I’ve decided to do in my situation. I plan on taking an appropriate gauge extension cord (and length) and will be cutting the female plug end off and hardwiring it to the “AC In/GEN” connection point in the MMP (Magnum Mini Panel), which has a dedicated AC In circuit breaker to provide protection and a switch. Thus, I’m left with a male end on the other end of the extension cord that I can plug into the 20-amp/120v outlet on the Yamaha portable generator (ef2000is). When not in use, I can coil up the modified extension cord and keep it out of the way.

          Thanks!!

  50. J. Reynolds says:

    Mike,

    Great information..I think I finally understand this stuff thanks to you. Here is my situation: I am planning on building an off-grid cabin soon. I plan on wiring the cabin just like a house to a small panel but that panel will never be connected to the grid. I will bring everything to a main panel and will install a 30 amp inlet and run a cord from my generator to the inlet to power the panel. Currently I have a 4000/3500 watt Champion that has a 30 amp RV style receptacle, two 20 amp 120 v standard receptacles, and a 30 amp twistlock receptacle. I have read here and on the Champion website that most Champion generators have a floating neutral. I have not tested the generator to confirm the floating neutral. The second thing I want to do is to also add a standard 120 volt inlet to the panel to be able to run the panel from an approx. 1000 watt inverter hooked to a solar/battery array by running a heavy duty extension cord from the inverter to the panel. This would allow me to run my lights and light appliances off battery power and then to go out and switch cords when I need the generator for a/c or larger appliances. I have read that when hooking an inverter to a panel that if the panel is G-N bonded that the inverter will trip, fail or fry because it already has a G-N bond. So essentially my generator is not G-N bonded and the inverter is G-N Bonded. This brings me to my question: Should I leave the G-N unbonded in the panel and use one of your G-N Bonding Plugs on the generator to create my G-N bond, and then the inverter could be plugged into the panel without damaging the inverter? Once again, the panel will never be hooked to grid power. Also, if I don’t bond the G-N in the panel do I ground the panel from the ground bus to a rod? and then ground the generator to a rod also? Thanks for your help.

  51. A. Gamble says:

    First off I want to give a big thanks to you Mike for your work on this site and also to everyone for their posts and replies. I have been searching for this type of info for awhile and about the best I could come up with was a hodge podge of confusing, contradictory info until now. Thanks to this site and reading through all the comments I feel like I finally have a good understanding of how to hook my generator to my panel (utilizing an interlock kit) safely. I do have a question though. I want to feed from the generator to a receptacle via a generator extension chord (10/4 with L14-30 male and female plugs). From the receptacle to my panel (10/3 w/ground). Since my generator has a floating neutral the neutral and ground will run through to the panel. At the panel I want to feed one leg to each side using 20A GFCI breakers. My generator “supposedly” will push 5700 continuous watts at 120/240 volts 30 amps. Given that setup should those breakers work or should I use regular breakers? The generator itself has over protection on it. About the biggest load that I plan to put on would be a coffee pot or electric skillet. I am mostly concerned with lights and plugs. Any help or thoughts would be much appreciated. Thanks again Mike. Tony

    • Mike Sokol says:

      The generator’s output breakers will protect it from over amperage, and you’ve sized the cable properly for a reasonably short run. However, be aware that the recommended gauges for for 100 ft runs from the panel to the outlet. So if your total length of run was say, 200+ ft) you might want to up the size of the wiring to 8 gauge to reduce voltage drop at full load. However, since you’re only using a pair of 20-amp breakers on the end of the run that will be safe and within code. And yes, the GFCI breakers should work as long as you have everything else wired properly. Remember for this type of installation you’ll want one G-N bonding point, most likely at the generator itself. However, if this is a permanent structure (cabin home?) then you should include a grounding rod connected to a G-N bonding point inside your service panel, just like any home.

      • A. Gamble says:

        Thanks for the quick response Mike. The distance from the box to the panel isn’t but about 20-25 ft max. I had hoped to use the bonding point in my panel. It will be supplying emergency power to house. Like I said mainly lights and a few plugs. We got caught with our pants down when the tornadoes ripped through Alabama a couple of years back. Since then we have been using extension cords when needed. I just want to make it a bit more “permanent”. I will keep on poking around here and reading. There is allot of great info regarding generators and electrical wiring in general in the comments. Thanks again.

        • Mike Sokol says:

          Yes, the bonding point in your panel with a floated neutral generator is the best way to wire this. I’m glad you’re doing this preemptively rather than waiting for the next disaster since when I whet to help one of my friends with a similar situation in NJ last winter, there were no local generator parts available. Lucky for him I was driving back from St. Louis that weekend where I could buy everything he needed for an emergency hookup. When the emergency comes to your own city, I can guarantee you there won’t be a generator or extension cord for sale within 100 miles. I addition to a generator I also bought and filled up six Blitz cans of gasoline, spare oil for the generator, extra generator extension cord, and a master disconnect for his breaker panel. It wasn’t the prettiest thing I’ve ever wired since I was doing this in the dark using flashlights and auto headlamps, but he and his wife were really happy when the generator roared to life and all his house lights and furnace came back on after 3 days of living in the cold. Best to do this install in the summer during daylight hours. I hate working in the cold and dark.

          • A. Gamble says:

            I imagine they were extremely thankful. I lived the through the very scenario you’re speaking about. Our kids were devastated by the tornadoes (they took a direct hit) in another city and we couldn’t even find gas to get to the hospital for several days. Not a good situation to be in so little by little we have been developing emergency plans/equipment. They even hint at bad weather now and we fill up, test batteries, get candles, etc. I know that it will happen again at some point. You are a good man to provide this valuable info. Another question and then I should be good to go. Given the fact that there is over protection on the generator (30A push button-type breakers) and there will be breakers at the panel (20A GFCI) for each leg, would an additional “master” breaker or disconnect prior to the electrical panel (30A) or be necessary or prudent?

          • Mike Sokol says:

            No real need for a master breaker in this situation since the gauge wiring will be protected from over-current by the generator’s 30-amp circuit breakers, and the panels 20-amp GFCIs will protect both your internal wiring from over-current as well as you and your family from shock hazards due to the GFCI trip circuit. However, if you were to go beyond just the two 20-amp breakers in the panel I think a master disconnect is a good idea, but probably not required by your local code. Most consumers aren’t aware that the NFPA-70E National Electrical Code is NOT a mandatory document for every state, county or city, and a local inspector (the AIC or Authority In Charge) can choose to ignore or override the “National” code as they see fit. So it’s always best to get confirmation from your local electrical inspector before doing any wiring project.

  52. T. Hargrove says:

    I just purchased a Honda EU3000IS generator which I plan on using to power my new gas furnace, a refrigerator, a freezer, and some inside lamps whenever we have a prolonged power outage. For now, I will be using extension cords until sometime later when maybe I can have a transfer switch installed. Based on your prior comments, it sounds like I will have to use a “Edison bonding plug” to run the furnace because this generator has a floating neutral. There are three power outlets on this generator, (2) 20A 125V standard plug, and (1) 30A 125V locking plug. My question is, does it matter which one of the 3 outlets I use to install the bonding plug? I’d like to install it in the 30A 125V locking plug outlet, so that I can then run 2 of my regular extension cords from the (2) 20A outlets, one to the furnace and garage freezer, and the other to inside the house. Will this be okay?

    • Mike Sokol says:

      Yes, you can use the twist-lock 30-amp receptacle for the G-N bonding plug. Just be sure you’re bonding the ground and neutral screws in the plug. You can confirm this by using a standard 3-light outlet tester on the 20-amp receptacles once you’ve got it running.

  53. The Edison plug referred to here is just a standard 3 prong plug with ground and neutral jumped…right?

  54. S. Strickland says:

    Mike~ I have (2) PH2100RPI powerhouse models that I have a parallel kit for, do you kow if I have to ground either of them with this Edison plug? We have a 50amp fifth wheel we are trying to power up.

    • S. Strickland says:

      Yesterday when we hooked the parellel kit to the generators and started them up, we got a (red) short light on the parellel kit.

      • Mike Sokol says:

        I just don’t know for sure since I’ve never seen or hooked up a Powerhouse generator. The problem is that NONE of the generator manufacturers will support any of my NSZ articles by loaning me any of their generators to try out. That includes Honda and Yamaha, two of the biggest manufacturers out there. So if you can contact your Powerhouse dealer and have them contact the generator manufacturer with a request to contact me, I’ll be glad to wire up a test if they’ll supply some loaner generators. But without factory support I’m just guessing how their neutrals are wired up.

  55. Shaun Patmore says:

    Hi Mike I recently purchased a GX12025i generator from Edisons in Australia. Its a 6Kw continious output single phase unit that I am wanting use it to power my portable 12 Sq meter LED video screen. When I first started the Generator I measured the output and found that I had 240V active to neutral and 120V between active and ground also 120V between neutral and ground. I installed an earth stake but this made no differance. I tested for continuity netween neutral and earth but it was oped circuit. The LED screen has around 20 switchmode power supplies in it that require a ground referanced neutral. I contacted the supplier with the question : can I bond neutral to ground without causing any damage to the Automatic Voltage Regulator? The reply that I just received was “It is not possible with this unit” I have a circuit diagram if you would like me to email it to you.
    What do you think?
    Cheers
    Shaun

    • Mike Sokol says:

      Shaun,

      From your description this generator sounds like it has a floating neutral, so bonding the neutral to the chassis ground should work. However, go ahead and send me the schematic and I’ll take a look to confirm that. Please email to mike@noshockzone.org

  56. tyler says:

    I have a HONDA EU3000IS that I am wanting to hook up to my tiny house built on a flatbed trailer. If I bond the generator using the Edison plug how would I properly hook up the panel in the tiny house. I have a standard Square D 125amp panel in the tiny house and everything is wired for ac. Would grounding my panel to the chasis need to be done if I have the Edison plug on the generator?

    • Mike Sokol says:

      Does your tiny house have a shore power receptacle like an RV? If so, then it needs to comply with RVIA wiring standards. So the neutral needs to remain unbonded to the box-ground inside your Square D panel. Then you can use a G-N Bonding plug on your generator when connected to it. Unless this is a permanently installed house, you probably won’t need any actual ground-rd. And since your generator’s frame/ground will be connected to the Square D panel via the EGC (Equipment Grounding Conductor – commonly called the safety ground) in the power plug, you won’t require a second ground wire between the Square D panel and the Generator frame. Do that make sense?

      • tyler says:

        Hi Mike,

        That is exactly how I ended up doing it. The only thing I don’t have is shore hook up. I ended up hardwiring the generator cable to my panel. I have a ground from the panel to my frame chasis and I left the oanel unbonded. I put the g to n bond using a edison plug on my generator. Everything seems to work! Does that make sense?

  57. David in Yanceyville, NC says:

    Mike,

    I am installing a 4000 Watt Pure Sine Inverter Charger 12 Volt Model #: picoglf40w12v120v (http://www.theinverterstore.com/4000-watt-12-volt-pure-sine-inverter-charger.html) in a 2008 Dodge 3500 Sprinter van to run 120 VAC electrical appliances for our shaved ice business. I have installed an additional alternator on the van ( 220 A stock and 270 A additional) to charge the two 4,000 watt AGM battery bank and a battery separator to prevent the vehicle battery from discharging. I have installed a 120 VAC 30 Amp RV style shore power twist lock inlet plug to power everything from a 30 Amp external supply and recharge the batteries. I have run 10 Ga wire from the shore plug to the inverter and 10 Ga wire to a breaker box. The inverter has the normal output lines of L-N-G. The breaker box has the normal 2 HOT input lines (expecting two 120 VAC inputs) a Neutral binding bar and a Ground binding bar. Because the breaker box expects 2 HOT input lines to the binding lugs, I had to purchase a “Double” breaker in order to feed all breakers in the box vice every-other-one. I am thinking I will need to bring the single HOT from the inverter to one side of the double breaker and simply jumper the HOT to the other side of the double breaker to feed all breakers. (Are you with me so far?) Okay. That done, now what do I do about the Neutral/Ground? From what I understand, I need to bind the (Earth) Ground to the vehicle chassis and “Float” the neutral or not connect it to anything but its own floating (Un-connected) circuit. Did I get that right?!?

    Second question regarding my generator. I have a Generac XP8000E Professional Series generator, Model 005708-0 XP8000E. We use this generator at special events while in the back of my pickup. The owner’s manual is unclear as to the Neutral Ground state and only says that you should Earth Ground the generator. From what I understand, that is OK. My question is … What if I were to run this generator in the back of my pickup truck? The pickup has a spray-in-bedliner and is completely isolated (electrically) from the generator. Should I Earth ground it to my truck and then to a ground stake OR install one of your N-G binding plugs? Again, the Manual is not real clear as to the N-G state.

    Your web site has been a wealth of knowledge to me and I truly appreciate all the time and effort you have put into it!

  58. Doug Myers says:

    I made the neutral-ground bonding plug as indicated in your very good article. I used it with my Honda EU2000i generator before which I could not get power to my 2015 Fleetwood 32VS Southwind. It worked perfect and I greatly appreciate your expertise in this area. We dry camp a lot in Forest Service campgrounds where the bigger onboard generators are not appreciated due to the louder noise level. Not many people are aware of this problem and I spent a lot of research time trying to solve it. Your article was clear and the illustrations great. Thanks again!!

    • Mike Sokol says:

      Glad I was able to help. Please post links to my generator article on any other forums or blogs you belong to. It really helps to spread the information everywhere it’s needed.

  59. Randy Chiappetta says:

    Hello, I’m making a wooden enclosed hobby trailer and I’m running 110v outlets for a fridge, A/C and lights. I will be using a Champion 4k parable generator. I’m a little confused of how I should wire the breaker box. I was going to use a main lug box with two or three breakers and power the box threw the rv 30 amp plug. Do I have to wire the panel like in a house? Not sure since I also want to use shore power when I’m at home. So would I run the ground and neutral to the panel and make your bonding plug for the generator. So when I plug at home the house breaker box will provide the bond that I need?
    T

    • Mike Sokol says:

      Randy, yes your trailer wiring will be similar to house wiring except for the fact that it’s treated like a sub-panel in your home, not the incoming service panel. So as you hinted, there will be separated neutral and ground wires for every receptacle which will NOT be bonded together in your trailer’s breaker box. And yes, it will get a Neutral-Ground bond from the campground pedestal, home outlet, or generator’s G-N bond. If you don’t have a bonded generator, then a simple G-N bonding plug is all that’s required. I do note that your trailer should have all GFCI protected outlets to meet code.

      • Randy Chiappetta says:

        Thank you, yes I will install the gfci if I’m correct I can have them first in the line and regular outlets behind them as the gfci will protect that circuit? Thanks again for your help. I have been hitting my head against the wall for several days. Lol

        • Mike Sokol says:

          Yes, that’s correct. A GFCI receptacle can be wired to protect other outlets downstream from it. But you need to be sure that you wire up the line and load sides of the GFCI receptacle correctly.

  60. Zach S. says:

    I have a brand new Honda i2000 portable generator and was having this issue, the generator would not provide ac power to my trailer and when plugged into 15 amp shore power on gfci on my house would instantly kick the gfi. Had an electrician friend of mine come over to look into it and within 5 minutes he discovered that whoever installed the converter in my camp trailer had the green ground wire and white neutral wire swapped and connected in eachother’s spot causing a faulty ground. First he made the common ground plug and it worked in the Honda generator, but that was before he discovered the faulty ground wiring in the travel trailer converter. Once he swapped places of the green and white wires in the travel trailer converter, then the generator successfully powered the ac power to the trailer without using the common ground cord cap plug mentioned in this article, and I am also now able to plug into 15 amp shore power from my house without kicking the gfci. If anyone is having the same problems I was having, I suggest first checking to ensure the ground and neutral wires are correctly connected in their trailer converter.

    • Mike Sokol says:

      Swapped ground and neutral wires are more common than you might think. They are indeed one of the most common reasons for GFCI tripping, and in large sound systems (my main gig) responsible for something known as “ground loop hum”. What was happening in your case was the neutral return currents from the load were being diverted to the ground wire instead, so the GFCI interpreted this load current as a fault to the earth via its sensing transformer, tripping the sensing circuit. Here’s my article about how GFCIs operate: http://new.noshockzone.org/rv-electrical-safety-part-viii-gfci/

  61. David in Yanceyville, NC says:

    Mike,

    I am installing a 4000 Watt Pure Sine Inverter Charger 12 Volt Model #: picoglf40w12v120v (http://www.theinverterstore.com/4000-watt-12-volt-pure-sine-inverter-charger.html) in a 2008 Dodge 3500 Sprinter van to run 120 VAC electrical appliances for our shaved ice business. I have installed an additional alternator on the van ( 220 A stock and 270 A additional) to charge the two 4,000 watt AGM battery bank and a battery separator to prevent the vehicle battery from discharging. I have installed a 120 VAC 30 Amp RV style shore power twist lock inlet plug to power everything from a 30 Amp external supply and recharge the batteries. I have run 10 Ga wire from the shore plug to the inverter and 10 Ga wire to a breaker box. The inverter has the normal output lines of L-N-G. The breaker box has the normal 2 HOT input lines (expecting two 120 VAC inputs) a Neutral binding bar and a Ground binding bar. Because the breaker box expects 2 HOT input lines to the binding lugs, I had to purchase a “Double” breaker in order to feed all breakers in the box vice every-other-one. I am thinking I will need to bring the single HOT from the inverter to one side of the double breaker and simply jumper the HOT to the other side of the double breaker to feed all breakers. (Are you with me so far?) Okay. That done, now what do I do about the Neutral/Ground? From what I understand, I need to bind the (Earth) Ground to the vehicle chassis and “Float” the neutral or not connect it to anything but its own floating (Un-connected) circuit. Did I get that right?!?

    Second question regarding my generator. I have a Generac XP8000E Professional Series generator, Model 005708-0 XP8000E. We use this generator at special events while in the back of my pickup. The owner’s manual is unclear as to the Neutral Ground state and only says that you should Earth Ground the generator. From what I understand, that is OK. My question is … What if I were to run this generator in the back of my pickup truck? The pickup has a spray-in-bedliner and is completely isolated (electrically) from the generator. Should I Earth ground it to my truck and then to a ground stake OR install one of your N-G binding plugs? Again, the Manual is not real clear as to the N-G state.

    Your web site has been a wealth of knowledge to me and I truly appreciate all the time and effort you have put into it!

  62. Robert L. says:

    Mike, clear and concise article…….thanks.
    love the clarity. seeing the reader issues and comments is very helpful, too.

    I have a floating neutral generator……..I made an n/g bond plug using a right angle GFCI module instead of just a standard NEMA 5-15 plug……..seems like it works

    but now I have some new questions about bonded vs floating neutral generators, running in standalone mode…….

    I’m wondering about the ground rod terminal on my generator…….

    1. What was it supposed to do in original floating neutral mode…?…..
    [ I’m interested in ground fault protection….my generator has equipment and ground blade bonded to the frame ].

    see some fault protection, see some conflicting info on whether GFCI and circuit breakers, work as planned in this mode…..is neutral and ground reversal in a cord or device a problem, here too?

    need clarity.

    2. Do I add protection against ground faults if I hook up to a ground rod while using an n/g bond plug to create bonded neutral mode……?….

    while I may get protection against faults on both hot and neutral circuits, and GFCI’s and overload protectors will work normally………I may actually create a fault path along the ground, by using a ground rod in this mode……[ is bonded neutral best for standalone?……..some writers say floating neutral is safer. ]

    OKAY. clarity needed again.

    best illustrations of the issues here :

    http://bit.ly/1CevRDg

    [ it’s an article with good stuff about hazard protection for portable generators used on movie set locations. ]

    any help you could give, would be greatly appreciated ……this whole field seems murky to me, and it’s important stuff.

    Robert L.

    • Robert L. says:

      Mike,…does that make sense? maybe I can simplify……

      Should I use a ground rod with the N/G plug?

      Am I getting fault protection in standalone mode?

      Robert

  63. Bruce says:

    Mike,
    In a previous answer you indicated you were trying to find out where the neutral ground bond was on a Troy Built Generator. Did you have any luck? If so could you tell me where it is. I called Troy Built and they would not tell me
    where it is. They wanted me to have a certified electrician call them. Conversation did not go very well. I knew more then they did. Troy built 7000w 10500 max Model 030477
    Thanks

    • Mike Sokol says:

      Bruce, I never did get any info from them. And yes, it’s surprising how little generator help desks seem to know about generator bonding and grounding. I’m still trying to get any manufacturer support for these articles and videos, but nothing so far.

  64. richard says:

    I will be making my own parallel kit for two yamaha f2000.I plan on buying a honda parallel cord,cutting it essentially making 6 ends to that i will be adding a 30 amp push button circuit breaker and on the load side(of the breaker) connect a 30 amp rv receptacle.My question is do i simply makeup 2 of these cord caps?or do i bond the grounded and grounding conductors at the box where the outlet and breaker will be?In addition does this “new”setup constitute a separately devised system therefore requiring, by code, bonding of that grounded conductor?And if so, do the yamaha parallel kits come with the neutral to ground bond?thank you

    • Mike Sokol says:

      While this is a separately derived system as defined by the NEC, it’s also a portable system that doesn’t require earth grounding since your entire system is floating. So the NEC doesn’t specifically require you to create a neutral bond connection. But any Neutral bond you do create must be at the generator itself or the transfer switch, not at the RV or boat’s shore power panel. However, you DO want to bond the EGC (Equipment Grounding Conductor) to any enclosure you build this into. And as far as the Yamaha parallel kit, I know that the Honda version doesn’t have a neutral-ground bond, and suspect that the Yamaha version doesn’t have a bonded neutral either.

      Does that help?

      • richard says:

        Yes very helpful.Thanx so I’m assuming that without the bonded neutral the honda unit will not run the trailers power and I assume we would then have to bond that grounding conductor?

  65. Kevin charles says:

    Thank you so much for this article. I spent my life savings building a mobile dog grooming trailer…spent thousands and ran all the electrical myself. I ran a 30 amp panel with 5 circuits..several outlets…lights..switches etc. I learned as I i installed. I bought a generac inverter generator to power it. After testing my electrical by plugging into house outlet …I was happy everything worked flawlessly. My first day grooming I was devastated when I started my new gen and plugged into it and had no power, no nothing….I couldn’t figure it out. I found your article and felt relieved
    . I had no idea what floating neutral even meant. Well I spent 5 bucks and made the simple plug end with a wire between neutral and ground, plugged it into a spot on my gen, then I plugged my shore cord in and I have power and I don’t even get shocked when I touch metal in my trailer. Thank you soon much..you are great

    • Mike Sokol says:

      You’re very welcome. Please pass this info on to any dog grooming forums or groups you belong to. And since you’re now “wiring” I suggest you purchase a copy of my book – “No~Shock~Zone – RV Electrical Safety” http://www.amazon.com/gp/product/B00L2DWBD8?*Version*=1&*entries*=0 and read it cover to cover. It’s also a great reference when plugging into campground and home shore power. This will give you enough knowledge to deal with any future electrical surprises and help keep you and your 4-legged customers safe.

      Mike Sokol

      • Kevin charles says:

        I’ll be telling everyone about this article as I belong to several grooming forums…also I’m buying your book now. You are a very good writer and to an electrical novice like myself, that’s saying alot. The again

  66. Tim Dey says:

    Mike,
    I have a somewhat different problem with the Honda 2000 series inverter generators. I have both the companion and the regular 2000 and the Honda parallel kit. I do have the neutral bond plug I use in my Mobile Suites Trailer. The trailer has a TRC Surgeguard Transfer Switch /EMS.
    Each of the generators by them selves work perfectly through the trailer generator system with the auto transfer switch and the bond plugs I made. The problem comes in when I then hook them in parallel and then to the generator plug in the trailer. The transfer switch will see (on the display) both generators but will only pull from one generator. I had the generators tested at a Honda dealer and in parallel they work correctly.
    I called Surge Guard and they told me that the Transfer Switch was seeing the second generator as bad power. I have tried one bonding plug and two bonding plugs in every combination but I can only draw 13-14 amps when connected in parallel.
    Do you know of any work around or fix for this. I suppose I could have someone wire in a connection down stream of the Transfer Switch but that would delete all of the protection that the transfer switch provides. As far as I can find there is no on / off switch for the Transfer Switch. I am stumped!

    Tim

  67. RoyB says:

    Fantastic site….Folks like you will find a place in heaven! Thanks for helping me with my EMS-HW30C and my Honda 2000 generator for my travel trailer. I’ll be making up one of those bonding plugs as soon as I install the EMS. Thanks!

  68. Ron Semarge says:

    Mike: Saw your site from another posting on the Heartland RV site. I just purchased a Landmark 5th Wheel that has the EMS/surge guard installed. I read in the multitude of posts above that the Honda 7000 IS (I forget the whole letter group) already has the bound neutral. My problem is that when I use my surge guard appliance it gives me a reverse polarity error as well as another error which I don’t recall right now. If I use the surge guard on normal pedestal power I get no errors. Any thoughts/help you can assist with is greatly appreciated.

    • Mike Sokol says:

      Are you sure it has a bonded neutral? I’m looking at a picture of the EU7000iS and it says “floating neutral” right on the front panel. Play the video I just made at https://www.youtube.com/watch?v=M-bTLdMjuqU you’ll see a simple way to confirm if you have a floating neutral or not. Just build a G-N bonding plug and try it. Nothing bad will happen if you already have a bonded neutral, but I’m betting that your generator does have a floating neutral which is giving you all sorts of strange readings.

      • Ron Semarge says:

        Mike: I checked my 7000 this morning and it has a different front panel than the one you are referencing. I did a Google search and found one with the front panel you describe but mine does not have that. I took a couple of pictures of my front panel and will happily send one of them your way if you desire. I did not have time to run the plug in tester this morning but I will try later today and let you know what I find. Thanks for your help, not only to me but all of the other fine folks on this list.

      • Ron Semarge says:

        Mike: During lunch today I went and checked the output with a three-light (dot type light which is several years old). In any case, it showed that it has an open ground (off, red, off for the light colors).

        Will try to put together one of the jumper connectors and see if that helps.

  69. Mike K says:

    Mike,
    You are an incredibly generous person with your time and a true educator at heart. This page has been a wonderful resource. I have an off-grid building I am wiring for generator or inverter power only. Someday I will likely add solar, Right now, however, the only power input to the GE panel in the building is via 10-3 AWG wiring to outdoor wet in use generator input receptacle (standard L14-30). The feed from the generator hookup runs straight to my panel where a 30A backfeed double pole breaker serves as the service disconnect because, as noted, there are no other sources of power to the building. My neutral and earth ground are bonded in the panel via the green bonding screw typical for newer home panels. The earth ground runs from the panel via 6 AWG solid copper to two 8′ ground rods as is again typical for earth grounding homes. When I need power to the building the plan is to connect to my generator or a pure sine inverter running of battery via the outdoor hook-up receptacle and a hook-up cable that goes from 20 A Edison to a L14-30 female plug compatible with my inlet. Any portable inverter or generator I would hook up in this situation is like to be floating neutral. I split the circuits in my panel so all essential lighting and receptacles are on just one of the hot legs into the feed breaker so I will often only need to feed one leg (black or red) of my inlet, but I might jumper the two hots in the L14-30 plug to power all circuits in my panel when needed (it’s a small panel with just 10 circuits. That shouldn’t be a problem because I do not have any multiwire or 240v circuits. So here are my questions. One is conceptual and the other is very practical for my situation.

    1. My pure sine inverter shows the same floating neutral condition as the small Honda and other generators. Basically, the receptacle shows the typical 60v on both legs relative to the receptacle ground and 120 across the legs. I completely understand how bonding the neutral and equipment ground (in my panel) will result in the typical household receptacle pattern of 120v L-N and L-G and 0v N-G. What has me scratching my head is how this works for a building with true earth ground (grounding rods), versus an RV that is basically insulated from earth. In an RV with a N-G bond and a generator or inverter producing 60v on the neutral you aren’t really bringing the neutral down to ground, you are bringing the equipment ground up to 60v but in opposite polarity to the 60v on the normal hot leg. But that shouldn’t be a problem because the potentials all behave like they should relative to on another when isolated from true earth ground. But what happens in a building (e.g. Home) when the neutral and equipment grounds are bonded and the equipment ground run to earth ground? Wouldn’t that cause some of that 60v on the neutral/equipment ground to flow to earth and reduce the potential between the L-N (and L-G) causing either low voltage problems or GFCI tripping on the generator or in the building’s electrical panel? I ask because our local code guy has fully bought into the NEC guidelines of requiring expensive AFCI or GFCI on every circuit in the building. I am concerned that he made me buy hundreds of dollars in those fancy breakers that monitor the neutral and hot for current variations, just to end up not being able to power them with a typical floating neutral generator or inverter the pits 60v on the neutral or when that 60v is dissipated to earth ground. Many homes are getting loaded up with AFCI and GFCI breakers in their panels, so probably others would have noted issues if this grounding to earth really was a problem for modern household breakers, but maybe others are using load side transfer switches that basically circumvent the home-side GFCI and AFCI breakers. Again, I have not actually run generator or inverter power to my panel to see what happens, but a couple different websites I saw basically claime tha you cannot bond N-G for inverters or generators with a 60-0-60v output.

    2) Also, why is there not a shock hazard created by bonding 60v neutrals to equipment grounds in RVs or other contexts? If the metal parts of appliances are now raised to 60v by bonding the 60v neutral and equipment ground and someone touches that housing while touching a true earth ground like water going down a sink, wouldn’t they be at risk of a 60v shock as that current runs to earth? Maybe the answer is they wouldn’t be shocked because the current needs to get all of the way back its source, not just to earth. Anyhow, this has confused me. It just doesn’t seem right to put 60v on the metal housings of equipment, but maybe that isn’t really what’s happening.

    Thanks again for being so dedicated to helping others,

    Mike

    • Mike Sokol says:

      Guess I’m going to have to write an article on center-tapped 120volt AC inverter outputs. This is a non-standard class of AC power, but fairly common in the pro-sound studio world (called balanced power there), as well as in many power inverters common to the RV industry. While I’m familiar with how this works, I’ll need to study some inverter schematics a bit before I’m comfortable explaining it to the public. So please stand by….

  70. Ralph says:

    I have a EG 3500 Honda generator that will not run the microwave, I made a N-G Bond plug and it did not change anything, microwave still not working. have any ideas??? Thank you in advance.

  71. Ralph says:

    Hi Mike, I have a Honda EG3500 generator that has power to all outlets and will power my 2016 Nomad 278RC camper except the microwave/coffee pot. I purchased an adaptor plug to fit the generator 30 amp to the 30 amp camper thinking it would run the microwave/coffee pot, did not work, so I made a N-G BOND plug tried it and that didn’t work either, do you have any other ideas to try. Thank You in advance.

    • Mike Sokol says:

      Does the coffepot and microwave work properly when plugged into shore power. Have you metered the outlet feeding the affected appliances? You’ll need to measure the voltage between hot and neutral to see if there’s any open wiring causing the problem.

  72. Jim Snow says:

    Hi,
    I have a DuroMax 4400EH and a single, unswitched transfer switch mounted on my brand new furnace. Installed by a licensed electrician. Furnace won’t work. Since the generator comes in beyond the service panel is it the case that I should use a bonding plug as you suggest? Also, generator grounded to 8′ rod in ground.

    • Mike Sokol says:

      I’m not sure if the DuroMax has a floated neutral or not, but there’s a good chance that it does. If that’s the case, then your furnace controller is looking for a bonded neutral-ground connection. It really doesn’t care about having an earth ground, but that’s even better. So it does appear that a G-N bonding plug will allow the furnace to run. Even if your generator is already G-N bonded, adding the external G-N plug won’t hurt anything, so go ahead and give it a try and report back.

  73. Nani says:

    Hi Mike,
    Will you be updating your book to include adding solar panels? We want to add some panels to our tent trailer (2006 Fleetwood Niagra).

  74. Dave Fullerton says:

    Mike. Yours is the clearest explanation I’ve seen on this topic and the G-N plug is a great idea. I’m planning on using and EZ single circuit generator switch. They’re available with a switched and un-switched neutral. They recommend the un-switched neutral for floating neutral generators like the Honda inverters. Does this change anything about bonding the neutral and ground on the generator? It doesn’t seem like an issue since the chassis ground on the furnace still goes back to the panel.

    • Mike Sokol says:

      You are correct. The service panel will provide the G-N bond for the furnace. The switched or non=switched versions of the transfer switch are to prevent double-bonded neutrals, which are a code violation.

      • Dave Fullerton says:

        The transfer switch with the unswitched neutral works like a charm with the floating neutral Honda. Big storm coming this weekend so maybe it’ll be put to use. Thanks for the help.

  75. Hi Mike, Great reading. Glad you’re around.

    My question is a bit off the above subject. I have 2 Generac 7550exl’s. I would like to know if I can parallel the two together in-order to double my output. if so, how would this effect my current set up? I am using an interlock system in my main panel so I can have my choice of items I would like to run. The reason for this question is to see if I can run my 3 ton central air conditioner as well as the other items. 7550 running 13500 surge for each unit. Model 1470-1, GN410 Nagano 15hp Engine. How would I go about safely paralleling the two? I converted both units to natural gas. I also UN-bonded this unit as per your video. If I were to use this unit for portable use I only need to reconnect the red wire back to the neutral correct? ( only removed one side and tapped off the other as per your video ). Once that’s completed no need for a ground rod correct? Not attaching to an RV just using it for tailgating, or just working power tools around the house.

    Thank You

    John.

    • Mike Sokol says:

      In a word, this is a big N-O. It simply can’t work. That’s because you you AC generators that use spinning magnets to create the 60-Herts output, which depends on the gasoline engine’s speed. So AC portable generators can easily run at 59 or 60 or 61 Hertz (Cycles per Second) and you would never know it. However, if you try to parallel two of them together there’s just no way to get two different gasoline engines to spin at exactly the same speed and phase. What you see a lot of RV owners do is parallel “Inverter” generators, which have an internal DC generator that makes something like 12 volts DC. That’s then stepped up to 120 volts and 60 Hz AC using a transistor circuit that can be “tuned” to another generator. That’s why Inverter generators can be run in parallel, while standard AC generator’s can’t be run in parallel. So don’t even try since you’ll likely destroy one or both generators in the attempt.

      • Hi Mike,

        Thank you for your answer. If I may stay on this subject for this one last time and this is just for my own FYI.

        Can you parallel more than 2 smaller inverter generators together? Example: Honda or Yamaha 1000 to 3000 watt inverter generators.

        I’m learning about small engines and have a great interest in them. You have been a great help.

        Thank You

        John

  76. Tim says:

    I have a Honda EU2000i portable generator with floating neutral. I would like to use it to provide emergency backup power for my furnace through a manual transfer switch AND use it for portable power tools.

    I understand the floating neutral is suited for powering my furnace but not OSHA approved for use with portable power tools. Could I eliminate the shock risk by using both a GFCI and a N-G bonding plug?

    Thanks,
    Tim

    • Mike Sokol says:

      Yes, you should be able to use a GFCI extension cord along with the G-N bonding plug. I’ve done this a number of times and it works perfectly. However, be aware that unless you add a ground-rod to the generator, the GFCI won’t trip.

  77. Robert L. says:

    “However, be aware that unless you add a ground-rod to the generator, the GFCI won’t trip.”

    could you explain a little bit more……..? I have a similar situation.

  78. Dean says:

    I have a Yamaha ef2000is. I connect it to a camp that is wired for lighting, toaster, radio, etc. We connect to the cottage through a 12-2NMB plugged into the generator outlet. I do not believe there is any ground in the camp. The generator sits outside in a shed, and it is not grounded.

    I noticed your comments about a floating neutral and grounding. What do I need to do to properly ground this generator? Should I put a GFCI on the entrance wire to protect against ground faults?

    • Mike Sokol says:

      It sounds like your cottage should be wired like a house. Check with a local electrician who knows the code for your area. If it does need to comply with residential code, then you’ll need to drive an 8 ft ground rod near your cottage circuit breaker panel. You’ll connect the ground rod to the service panel ground bus, which will have its ground bus and neutral bus “bonded” with the little green screw supplied with the panel installation kit. Any exterior outlets should have a GFCI breaker, as should any kitchen or bathroom outlets. The generator will get its G-N bond from the cottage service panel.

      • Dean says:

        Mike, There is no power from the street, this is truly a mountain camp. It would be like using a generator to run a light for your tent. There is no breaker panel on the camp. There is an extension cord from the generator to an outlet at the camp. There are about 10 lights in the camp, a toaster and a microwave that is used very little. The breaker on the generator is the only breaker in the system. It’s been that way forever. Why wouldn’t I treat it like an RV that doesn’t move?

  79. Rory T. says:

    I am sure this has been answered. I apologize if so. Bought new Champion generator, floating neutral. Tried to run my Lennox gas furnace and the fan starts for a few seconds and then quits. This repeats about every minute.
    Will making the G-N bonding plug correct this situation?

  80. Minh Pham says:

    Hello Mike,

    I have a Duracell (DS10R1) Invertor Generator with just one (1) 120V AC outlet. Can I plug a power extension cord (one of those that have 6x plug with on/off switch – non-Surge) into the Generator’s AC outlet, and then use the G-N plug to plug into one of the 6 expansion plug to G-N my generator to create a G-N?

    On the generator, it clearly marked “NEUTRAL FLOATING”

    BTW: Thank you for taking the time to explain this to all of us.

    Best Regards.

  81. Michael Howard says:

    Mike, your site is really interesting and informative. I’m sure everyone appreciates your help very much. I have a question about converting my Briggs & Stratton 6000 generator to floating neutral. The schematic shows that the neutral and the ground are attached to the frame separately. Which one should be disconnected to create a floating neutral. Thanks so much.

  82. Mike Sokol says:

    Well, that’s a matter of semantics. According to the NEC, it’s a bonded neutral. I call it a Ground-Neutral Bond just to clarify it a little better. I would guess that someone calling it a “grounded neutral” is really a “bonded neutral”. Earthing that bond via a ground rod is something totally different.

  83. Steve Erickson says:

    Thanks Mike this has been quite helpful. I read some of the posts, skimmed most of the posts and skipped a few, so if this has been asked and answered I apologize.

    Ice Castle RV/Fish House, No electronic devices except a small Fridge and a on-board battery charger. Generator LIFAN Energy Storm 1500 Watt. http://www.homedepot.com/p/LIFAN-Energy-Storm-1-500-Watt-97-cc-Gasoline-Powered-Portable-Generator-ES1500/202196127

    When I plug this little generator into the RV the GFCI inside the RV trip.

    The solution is to make G-N Bond plug, correct.

    This little generator only has one 120 amp power outlet.

    From what I have read here, I can jumper the male end of an extension cord and use that to power the RV. Is this correct?

    What about using a regular extension cord and plugging a G-N Bond plug into the GFI inside the RV itself? Will that solve the problem without making a dedicated extension cord, or do I have to jumper at the source (generator)?

    Thanks for the help.

    Steve

    • Mike Sokol says:

      First of all, you must NEVER G-N jumper the male end of any extension cord. That must be a completely separate bonding plug that can’t be used for anything else. And it must be plugged into the generator, and nowhere else. As to why your GFCI trips inside the trailer, there must be a wiring problem downstream of the GFCI. I do a lot of testing with a high-sensitivity clamp-amp meter to sort this out. But you can just unplug everything and plug things back in one at a time until the GFCI trips. Then that’s the culprit.

  84. Dustin Signor says:

    I have a few questions after reading this article. I have a 2016 Coleman trailer and a powerhouse 2100pri generator. The generator has a grounding lug. Can I run a wire from the ground to the trailer. Will it help with anything. Also in the instructions it says do not connect the generator to an automatic transfer switch as it will damage the inverter. So do I need to bypass the trailer transfer switch. If so. How. Last question will the N-G plug help on my setup. Thank you.

    • Mike Sokol says:

      If you’re running off of generator power, and distributing the AC to multiple locations such as another RV or even an outside table, then adding a ground rod to your generator will improve the electrical safety a little bit, but only if you’ve also included a G-N (Ground Neutral) bond either via the RV’s transfer switch, or with the generator G-N bonding plug I designed. Most of the time you don’t need to worry about a ground rod at all.

      As far as neutral bonding, I doubt that your transfer switch has this G-N function since it’s likely designed to connect your RV to shore power, correct? You really need to get someone to look at the schematics of your Coleman’s electrical system to see how the transfer switch interacts with the onboard inverter. Who did you buy this trailer from? If it’s a 2016 model then one would hope that your dealer knows how to hook up a portable generator. If they need training on how to do this, then have them shoot me an email and I’ll set up a training session for their technicians.

      • Dustin Signor says:

        Sorry. I should have been more clear. The trailer doesn’t have an inverter. This was the instruction book for the generator. It says don’t hook up to auto transfer switch or it will damage the inverter in the generator. Are they talking about a residential auto transfer switch. thanks for the answers.

        • Dustin Signor says:

          Also I don’t think my trailer has a transfer switch. I’m going to add a go power 30 amp transfer switch so I can add an inverter and solar.

          Thanks.

  85. Joe T says:

    Hi Mike,
    I read every post on you noshockzone forum regarding G-N bonding plugs, used on generators with floating neutrals. I want to thank you for your generous wealth of knowledge that you share with us all.

    My situation is somewhat similar, and I need some clarification please. I have a Honda EU 6500isA generator, mounted on my dog grooming trailer that I built myself. I distribute power via a small electrical panel with less than a dozen circuit breakers installed, for pumps, hair dryer, lighting, receptacles, A/C, etc. I use a pigtail plug from the 4-prong twist lock off the generator, and hard wire directly to the electrical panel in the trailer, using only 1- hot leg, 1- neutral, and a ground to feed the panel. I leave the voltage selector (120/240v) rocker switch on the generator set on 120-volts. The AC unit plugs into the other 120 volt, 3-prong twist lock outlet exclusively. The duplex receptacle on the generator isn’t being used at this time.

    Being an electrician for nearly 30-years. I figured I would treat the electrical panel as a sub-panel, and NOT bond the neutral/ground bus internally. So, the neutrals and ground wires are separated (isolated neutral) inside the panel. This trailer works 100% off Gen power. Going on 4- years now without any problems, I just now discovered issues with new LED lamps not working in the trailer, when I tried to replace the fluorescents. After doing some research, I found it is the floating neutral that the LED’s don’t like, as they are designed to work in residential/commercial buildings a w/ bonded N-G system. I stayed with fluorescent lamps for now. Not a big deal.

    My only concern is SAFETY!
    1- I can install the Edison bonded N-G jumper at the generator, but in one of your posts you mentioned that this particular inverter generator requires the neutral to float in order for it to work properly, and that you were going to check into that some more. Is this still an issue?

    2- Can I simply bond the G-N bus inside the breaker panel on the trailer instead? You mentioned it’s NOT to be done, however this would be the one and only location, as I will not be plugging into shore power ever. I basically would be converting the SUB panel into a main panel, matching the G-N bond that’s on my home electrical service.

    3- I have not bonded the ground bar inside the panel to the steel frame of the trailer with an equipment grounding conductor yet. I am only using the ground wire going back to the generator, through the pigtail cord. Should I bond the panel to the chassis steel as well?

    I know the entire system is floating being on a trailer, and this falls under a different set of rules, however I’m not familiar with them all. Please give me your opinion here. Thanks for your advice!

    Joe

    • Mike Sokol says:

      Joe,

      These are good questions. First of all, you really DO want to treat your trailer’s electrical system like a sub-panel in a house. That means there can be NO Ground-Neutral bond inside the box. That’s in the NEC code. And you DO want to bond the incoming EGC (Equipment Grounding Conductor) safety ground bus to the trailer’s frame. That in the RVIA code. The question of what to do with the generator neutral bond is the only thing in question. I do know that EVERY factory installed generator in an RV does have a G-N bond, typically made inside of the generator transfer switch. So if you take a cue from that, then your generator needs to provide the G-N bond, just like the service panel in a house provides the G-N bond for any sub-panels. While some may argue that a simple Edison plug with a G-N jumper might be in code violation, I would argue that it’s about as simple a fix as you can get. However, if you want to avoid that argument, then you should make a short twist-lock to twist-lock jumper cable that fits your generator’s outlet, and create a G-N bond inside of it. That should address all of the above concerns, and is 2nd best way to do this. The gold standard would be to create the G-N bond inside of the generator itself. However, while on some generators an internal bond ‘s an easy fix, on many of them it would void the warranty, which I would never advocate. Give this a try and let me know how it all works.

      • Joe T says:

        Thanks Mike for responding so quickly. Well I tried it, and as long as I do not plug in the A/C unit in the other 3-wire twist lock outlet (120v/30 amp), I’m fine. Here’s what I have: Without the G-N Edison jumper, plugged in to the generator, I have: 120- v Neutral to Ground, and 120-v hot to Neutral, and ZERO volts hot to ground. This is how I’ve been running it for the past 4-years, and everything works fine, with the exception of crazy voltage readings!

        Put the G-N jumper in: with the electrical panel plugged in to the 4- wire, 120-v, 30- amp twist lock receptacle (selector switch set to 120- volts only), and without the A/C unit plugged in to the other twist lock receptacle, I read 120-v Hot to Neutral, 120- v Hot to Ground, and zero v Ground to Neutral. Just like it should be. Everything works great inside the trailer, however A/C unit is turned off.

        Now for the fun stuff…. With the G-N jumper still plugged in, and the A/C plugged into the other 3- wire 120-v, 30 amp twist lock receptacle, and the electrical panel still plugged in, I start up the generator, and it immediately goes out on overload on the A/C circuit (30- amps). Unplug the A/C unit, reset the circuit breaker on the Gen, and all is good. Plug back in, overload, then trip. The electrical panel circuits are not effected by all this.

        Remove the G-N Edison plug, start up the generator in a floating Neutral state, and the A/C comes on, panel circuits all on, everything running strong, but got those crazy voltage readings again. I’m not comfortable running it this way, but it seems that’s the only way it can handle the loads. I also thought about running the A/C out of the electrical panel with the rest of the circuits, but there’s no way the 30-amp twist lock can handle all the combined loads from one outlet. This is why Honda told me to plug the A/C unit into its own twist lock receptacle. I can’t figure this one out. if you can, You’re a rock star! Please let me know what you think.

        Thanks again!

        Joe

  86. […] ground will have to be connected. If your generator has an unused output, you may be able to add an external neutral-ground bonding plug (PDF format) otherwise you should have a qualified electrician modify your generator (though this […]

    • Mike Sokol says:

      Unless you’re using a very inexpensive Chinese generator (with a 60+60 volt output), then it’s safe to G-N bond any inverter generator. Most gear won’t care if the neutral is floating, but many home furnaces and RV voltage monitors will detect it as an open ground and shut down. The G-N plug is a simple way to correct this without rewiring the generator internally. Some generators have an access door to bond it internally, but none of the Honda or Yamaha 2K or 3K generators have a simple way to do it internally. That’s why my G-N plug can help.

  87. My search for an answer began when my Yamaha 2000 would not run our furnace during a major snow storm. I was checking my inverter/generator for a problems with a Sperry Instuments circuit tester and it showed an open neutral among other irratitic readings each time it was restarted and the tester plugged in. Your solution makes sense to correct the situation so the furnace will run. We also use the inverter/generator on our cruiser boat via a cord plugged into the inverter/generator and plugging the cord into the boats shore power connection. The reverse polarity light will occasionally flash. Everything seems to work fine. This being said we have not used it in this way since due to safety concerns. My question is should we be using the same neutral/ground bonding plug in the inverter/generator? Thank you in advance for your assistance.

  88. Brian says:

    Mike, Great article!
    I thought I should try out the testing method you offered on my Yamaha 2400is.
    When I plug in the tester I get all three lights coming on. Is this a problem if I use this generator with my trailer?
    I have tested the generator with the trailer and it runs the A/C and the onboard battery charger with no problem.
    I made a G-N plug but I am afraid to use it on the generator since I don’t understand why there are all three lights coming on.
    Thanks, Brian

    • Mike Sokol says:

      Brian,
      If you don’t have any problems with your RV’s electronics shutting down due to sensing an “open ground”, then you probably don’t need a G-N Bonding plug. However, many RV voltage monitoring systems will shut down with a floating neutral, as will some RV refrigerators and home furnaces. In that case, you’ll need to create a G-N bond, and my jumper plug is the easiest way to do this on any inverter generator with a floating neutral such as you 2400is.

  89. Doug says:

    Mike,
    I have purchased two Champion 2000w inverter generators with the Champion parallel kit. This parallel kit sits between the two generators when they are connected together. I put these two generators with the parallel kit and placed my Camco 55312 125V 30M/30F Amp Dogbone Circuit Analyzer into the 30 amp socket. It read that there was an open ground so I did not hook my travel trailer to the generators. My question for you is: would I put one of the generator-only G-N bonding plugs in one of the two generators or should I put one in each of the generators as they both are wired into the 30 amp parallel kit? Sorry if this was answered earlier, I read the above comments and did not see this specifically addressed. Thanks for your time, this has been an eye opening lesson in using a generator to power my travel trailer.

    • Mike Sokol says:

      You only need to G-N bond one of your generators in a parallel hookup. That should be done on the primary generator feeding the shore power, rather than the secondary generator. That’s because on Honda parallel kits and connecing wires aren’t polarized.

  90. David Randall says:

    Mike,
    I have a PowerHorse portable 2000W inverter generator from Northern Tool. It does not have GFCI protection or an internal bonded neutral to ground connection. It does have a grounding lug to be connected to an earth ground rod (as per the manual). Talking with a GFCI extension cord manufacturer, they claim their GFCI will not work unless the neutral and ground are bonded. Okay, I can use the Edison plug jumper you’ve talked about so many times in your articles to accomplish that bonding requirement. They also claim I do not need to hook up the grounding lug to an earth ground rod for the GFCI extension cord to be effective. If true, that’s great because a portable generator was made to be moved around and driving a new 8 foot rod every time I use it seems ludicrous. Does this sound plausible to you to use the Edison plug jumper with a GFCI extension cord and no earth grounding rod to keep me and my family safe? We use the generator near the water to help power our floating dock and safety is always a concern when using it. Your thoughts, please?

    • Mike Sokol says:

      If you add a G-N bond and don’t use a ground rod, you’ll be safe as long as you don’t distributed power to multiple locations. That is, if your generator was supplying power to two or more RV’s, then you really need a ground rod to be safe. But a single RV is safe without a ground rod. And the G-N bond is only really required if your RV’s electrical system has some sensing circuit that shuts down power with a high Neutral-to-Ground voltage test.

  91. Rhonda Perry says:

    On the same line…. I have a little off-grid shed that has a 100 amp panel with cord to connect to 5000 Honda generator or my solar inverter. The lights and gfci work great. But after a relative advised me to test the receptacle with a receptacle tester, it says “open ground”. I’ve checked over and over, even disconnecting all but the one gfci, but it still says “open ground”.

    From your blog here, I’ve learned that maybe the problem is that there is no bonding. Does that sound right?

    Thank you!

    • Mike Sokol says:

      Your RV’s shore power plug needs to be connected to something with a Neutral-Ground bond. So many generators have floating neutrals and need a plug such as my G-N generator bond, and your solar cell system should have an internal G-N bond connected. Please check with the inverter manufacturer for the best way to do this.

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