I've been researching portable generators, and I have learned that models with a floating neutral need to be grounded. Some people say you can bypass this requirement by plugging a "bonding plug" into one of the generator's outlets.

These bonding plugs are basically a normal 120V electrical plug with the neutral and ground pins connected to each other.

Is this a safe and legal (in the US) approach to portable generator grounding?

3 Answers 3


Are you talking about just plugging in a plug with no cord, that internally connects Neutral to Ground? I imagine it would work perfectly... until someone who doesn't know what it's for assumes it's a simple outlet cover and unplugs it to plug something else in to that outlet.

As far as whether it's code-legal, probably not. Code tends to frown on things that make it easy to create a dangerous situation inadvertently, which this certainly would do. The electrical code (AFAIK) doesn't say anything about this situation directly though -- instead, the code says you must use equipment that is UL Listed (or listed by some other NRTL, such as ETL), and that you must follow its instructions, which were part of the UL listing. If your generator says that you can bond neutral and ground with a "bonding plug", then it's legal to do so -- but you probably won't find any that say that, because I don't think UL would approve a bond that can be removed during operation. Instead, the instructions will probably say how to open up the unit and bond N to G internally, or it will say that you must use a 4-wire feed to a panel that bonds N to G already.

  • UL, and other NRTLs best I can tell save for CSA in Canada, don't really list small portable generators anyway -- there's been some major breakage going on in the standards-development process for portable gensets. PGMA G300 is the closest thing we have to a consensus standard, but it lacks NRTL imprimateur (UL doesn't list to it, and I don't believe ETL or others do either), and it doesn't speak to the OP's question Feb 26, 2021 at 1:17
  • 1
    I agree with the idea that bonding plugs may make it easy to do the wrong thing, but they could actually make it easier to do the right thing in one scenario. If you have a portable generator that you use for multiple applications, sometimes powering a structure and sometimes powering a simple extension cord, you may end up moving the internal neutral-ground jumper a lot. If you can't easily see the state of that jumper, it would be easy to make a mistake. A bonding plug (especially if properly labeled) would make it easy to know if the neutral line is bonded to ground or not.
    – mrog
    Feb 28, 2021 at 18:11
  • 2
    @mrog -- yeah, I'd probably use the "big receptacle" (NEMA L14-30 or CS6369(receptacle)/CS6365C(plug)) on the generator for the bonding plug to avoid confusion with an ordinary plug when the generator is used in a portable app Mar 1, 2021 at 3:43

Generator grounding plugs are going into the 2023 NEC.

And this is why you need one:

"when using a floating neutral generator to power an RV, if a short circuit develops between the hot wire and RV chassis, there is no return path for the fault current to trip the generator circuit breaker."

  • It would help to have a citation so readers can find the relevant part of the 2023 NEC. Is someone able to provide this?
    – mrog
    Nov 18, 2022 at 17:44
  • 1
    I've contacted Mike Sokol to find out if he knows where it will be.
    – hyperlogos
    Nov 19, 2022 at 20:12

Grounding plugs are not approved. There is no "standard" thru UL or Intertek ( or other testing labs)that I am aware of. ( if you have one with a label please advise). Grounding the neutral is not the same as grounding the frame of your generator and should not be confused as such. Grounding the frame is associated with a fault current "in case" there is a issue. Grounding the neutral at the generator with a plug is a code violation and you are creating a "new path" for the unbalanced load to go to ground. Neutrals are only bonded at the main panel or means of disconnect where it enters a structure.

  • 1
    Many, many generators have a bonded neutral -- this is often required for use as a portable/jobsite generator, and is fine from a Code standpoint provided the generator is treated as a separately derived system when it's connected to a building Dec 15, 2021 at 2:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.