Generator Grounding & Bonding Basics (Rerun)

How to connect a floating neutral generator to your RV

I had lots of questions yesterday about grounding and bonding generators. Here’s a rerun of my more advanced article on this topic.

Dear Mike,

I purchased a generator for the RV. It is a 3500-watt unit and came with an RV 30-amp outlet. I thought that it would tie the ground and neutral together but upon doing a continuity check on it all three poles are open. The generator does have an earth ground connection.

Do you recommend using the earth ground connection with a grounding rod and would a foot deep be adequate for a copper rod? Or should I just tie the ground and neutral together, and where would be the best place to tie together. Your help would be greatly appreciated. —Gary

Dear Gary,

This is something I’ve written about many times before, so I’ll condense it down into a few simple rules and link back to more complete articles if any of you need to dive in deeper.

What about a ground rod?

You DO NOT need to use an earth “grounding rod” for any portable generator that’s powering a single RV. A grounding rod is primarily there to provide a path to earth ground for lightning. It won’t have a low enough impedance to cause a circuit breaker to clear (trip) from fault current.

Note that all the major metal parts of an RV should be bonded to the RV chassis which forms a local ground-plane. That ground-plane can be floating above earth potential when running on generator power.

However, if your RV is connected to shore power, that ground plane will be bonded to the service panel’s neutral bonding point via the shore power cord set and pedestal connection. That will then be grounded to earth by the service panel’s grounding rod(s) when you’re on shore power.

What about big generators at a rally?

However, if you’re using a large generator to distribute power to a number of RVs for a rally, that’s an entirely different thing which will require a grounding rod.

What about inverter generators?

Very few (if any) inverter generators have a built-in Ground/Neutral bond. That’s generally not an issue when powering an RV, but it does complicate troubleshooting of electrical problems. And it will cause an EMS / Intelligent Surge Protector to shut down the power since it will interpret any G-N differential voltage as an open ground condition (which it is). There are lots of UL and NEC reasons for this, but just know that it’s normal for that style generator.

What’s a generator bonding plug?

The simplest way to bond an inverter generator is to use a G/N plug I invented in 2010. Just plug it into any 15- or 20-amp receptacle on the generator panel and it will bond the entire generator’s electrical system. Here’s a link to where you can purchase one on Amazon.

A generator transfer switch does the same thing…

No, this is not a cheater plug designed to fool anything. If you have a built-in generator on your RV, this same G/N bonding function is accomplished in the generator transfer switch.

Since you don’t have a transfer switch on your RV and are plugging in your shore power cord directly to a portable generator, the RV’s electrical system is expecting a G/N bond from that shore power connection. My G/N bonding plug design just gives the RV electrical system what it expects, nothing more.

Testing a generator for a floating neutral

The easiest way to know if your generator has a floating or bonded neutral is simply by using a 3-light outlet tester. See my video on how this works HERE.

Let’s play safe out there…. Mike