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RVelectricity – Just Ask Mike (J.A.M.): Generator bonding basics

By Mike Sokol

Welcome to my J.A.M. (Just Ask Mike) Session, a weekly column where I answer your basic electrical questions. If you’re a newbie who’s never plugged in a shore power cord (or ask – what’s a shore power cord?), or wonder why your daughter’s hair dryer keeps tripping the circuit breaker, this column is for you. Send your questions to Mike Sokol at mike (at) noshockzone.org with the subject line – JAM.


Dear Readers,
I’ve had several emails this week about bonding inverter generators, so now is a good time to rerun this J.A.M. Session from 2019 about how it works. I have a lot of experience with this since I invented the generator Neutral/Ground Bonding Plug nearly 10 years ago, and it looks like it will finally be accepted in the next National Electrical Code® (NEC) cycle. Pretty cool, eh? So here it is with links to other articles I’ve written about the basic principles.


Dear Mike,
Enjoyed your talk at the Airstream Rally in Doswell, VA, last year. I use a Champion 3000 dual fuel generator and when I plug my Progressive Industries EMS into the Champion I get some funny readings and it shuts down. I’ve plugged in a 3-light tester to the generator and it shows open ground. Any thoughts? Thanks. —Stan White

Dear Stan,
I’ll bet you’re seeing something that looks like this. One amber light in the middle lit up, and the other two lights off or glowing dimly. What does this have to do with the EMS shutting down? Well, it’s doing this same sort of test internally, and because it’s finding an open ground, it’s shutting down power to the RV.

All grounds are not created equal

However, this really has nothing to do with grounding your generator or RV to the earth. Both the EMS and the 3-light tester are expecting power that looks like it’s coming from a wall outlet or pedestal, not a generator.

That’s because most generators (and all inverter generators) have something called a floating neutral, where the ground and neutral are isolated (unbonded) from each other. The reasons they do this are a bit too complicated for this JAM Session, but know that it’s perfectly safe to bond the generator neutral and ground together so it’s wired like a pedestal outlet already is.

Again, this has nothing to do with the earth ground (the dirt beneath your feet). This is a neutral-ground bond, exactly like the power company does in your electrical service panel, and the same as any installed generator in an RV. I just made it simple to do with a portable generator.

A super simple solution

The easiest way to accomplish this is by simply plugging a Generator Bonding Plug into any unused outlet on your generator, and that bonds all of the generator outlets together. I invented this Ground/Neutral Bonding Plug, which is now available from Southwire and Micro-Air. It’s simply a dummy 15-amp plug with a jumper wire between the neutral and ground contacts. Again, this is exactly how your power company service panel is wired, so there’s nothing weird about it.

So if you’re trying to get your EMS Surge Protector to work on your inverter generator, it could be as simple as plugging in this special generator bonding plug.

References

For my BIG article on generator neutral/ground bonding, read it HERE.

If you want to purchase a ready-made generator bonding plug from Southwire, go HERE.

OK, everyone. Remember that electricity is a useful and powerful force, so we all need to pay attention to safety precautions while using it.

Let’s play safe out there….

Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.
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Velo-chi
8 months ago

Mike, you’re a legend. I think this will solve my F150 ecoboost 2kw generator <–> Ecoflow River pro charging problem. I can charge the Ecoflow portable battery no problem in my house, and can power any other appliance rated less than 2kw from the truck’s generator, but I every time I plug in the Ecoflow to charge from the truck’s built-in floating ground generator, I get a ground fault indicator error on the truck’s message panel.

For reference, the F150 pro power is a floating neutral on the gas engine trucks (which I have) and a grounded neutral on the hybrid trucks (which can supply higher voltage). I think this is to meet OSHA GFCI compliance requirements.

Anyway, do you think adding a neutral ground plug to the truck’s bed outlet when charging my portable battery from the other outlet will do the trick? FWIW, I’m confident the onboard generator can handle the battery’s charging amperage (it draws ~700w to charge) because the truck routinely powers 1500w toasters, etc.

Mike Sokol
8 months ago
Reply to  Velo-chi

Yes, I do believe a generator bonding plug would work for this. Please take a picture of your setup and send it to me.

Roland
1 year ago

Can you use the same “Bonding Plug” if you have an inverter that has a floating ground?

BadWolfe
1 year ago

Thanks Mike. I purchased one and threw it in my RV Toolkit.

Brad Teubner
1 year ago

That’s how I wired the adapter to plug the 50A RV into a 50A welder outlet. 😎

William
9 months ago
Reply to  Mike Sokol

Mike,
Thank you so much for your concise articles they are really helping and please forgive me if this post seems long-winded I’m trying to be as concise as possible.
I read your article on open and bonded generators with some interest. The reason for my interest is I purchased a Firman T07571 generator that is bonded ( Yes, I checked just to make sure the generator was bonded by using a volt ohm meter and placing leeds between the neutral on the generator 110 plug and the generator frame and I do have continuity). At the back of my premise I have a 100 amp main service panel sitting next to the meter base. I checked in the main service panel. The main service panel also has a mechanical generator interlock. Both 110 feeds from the generator to the premise are connected to an interlock breaker but the neutral wire from the generator input plug is attached to the neutral bus. In the main service panel. The panel feeds both neutral and ground are strapped together on the neutral bus, the ground wire then goes out of the base of the main service panel down to a 8-ft copper rod which is pounded into the ground.
My question is this, if I understand your previous article running a bonded generator to a main panel in which the neutral and ground are bonded will not work due to back feed between the premise and generator neutral and ground? Everything I have read tells me I can only have the neutral and the ground bonded together in the main service panel ( first panel after meter base) and nowhere else? Once only?
If this is so wouldn’t it be possible just to disconnect the ground wire from the generator plug? This would eliminate any back feed between the generator and the premise. The premise is running bonded from the neutral and ground on the neutral bus, and the generator is bonded internally.
What am I missing here?
Again thanks for any guidance you might be able to offer.

John
1 year ago

Any reason to use this if you’re not using an EMS surge protector?

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