cLAYH

This has been a good read.

Recently I bought a used RV that the previous owner said not to plug it into a GFCI outlet as it will trip it. PO claimed that it was caused by the converter and is a common problem on many new RVs.

Now reading this I'm wondering if I shouldn't be taking a closer look. Everything works fine and I've never been shocked but if I do plug it into my outside garage outlet which is a GFCI it will trip. Run a cord from inside the garage and all is good.

In fact the PO even included a homemade cord with the ground plug removed in case I ever HAD to plug into a GFCI. He did warn me to be careful and not plug it in backwards. So far I have managed to avoid using it.

So has anyone else heard or convertors of battery chargers tripping GFCI outlets?

jmsokol

First of all NEVER use an extension cord with a lifted ground to stop a GFCI from tripping. That's not only a violation of the national electrical code, it's also risking your life.

Every piece of UL listed gear produced has a maximum amount of ground leakage allowed. But remember these leakage currents are additive, so turning on multiple devices can cause the leakages to add up above the 5 mA threshold trip point of a standard GFCI. One culprit I know of that's particularly troublesome is "surge strips" those multiple stick outlets with MOV spike protectors. It appears that many inexpensive surge strips will leak between 2 to 3 mA to ground when everything is operating normally. So one surge strip won't cause enough leakage current to trip a 5 mA GFCI, but two surge strips plugged into your RV probably WILL trip the external GFCI. Interesting, isn't it?

Also, if your inverter is causing the trip, then it probably has a leaky noise reduction capacitor in its output. That's something that should be repaired since it could short out at some point and create a very dangerous low-impedance ground fault.

For troubleshooting your RV, a basic clamp-ammeter you can buy in any big box hardware store can help you find the source of the leakage. By building a simple break-out cable for the shore power connection, you can measure the leakage currents on the green ground wire in your extension cord. Then by turning on one appliance or electrical system at a time in your RV, you'll quickly see what's leaking excessive current to ground. Once you identify the problem, it's time to get the offending device or appliance fixed or replaced.

For more information, see my article on GFCI theory and troubleshooting at http://www.noshockzone.org/rv-electr...oubleshooting/

Mike Sokol
mike@noshockzone.org

jrs_dodge_diesel

Clay, you can turn off all of your AC circuits at the power panel inside your camper to help isolate what is causing your GFCI to pop. Turn off everything and then plug in your camper. As long as it did not trip the GFCI (bad cord can cause that), then turn on your circuit breakers one at a time until you find the one that trips the GFCI. That's a simpler way of troubleshooting your problem.

Making a breakout cord and using the ammeter like Mike said above is a better and more in depth way to find your problem though.

jmsokol

Yes, starting with all circuit breakers off and turning them back on one at a time is a quick and dirty test. But remember that leakage currents are additive, so you can easily have a few with 3 or 4 mA of leakage that's not enough to cause a 5mA GFCI to trip, unless you have two circuits on at the same time. So if you don't get a single circuit to trip the GFCI, then a breakout cable with a clamp ammeter will help speed the troubleshooting.

SOhappy

BTW, I'm not an electrician (obviously ) but I'm guessing that method didn't work in my case because the short was between ground (green) and neutral (white). The breakers are on the hot (black) wires. I had to open the panel and measure resistance between the ground bulkhead and each set of white wires.

j_martin

That fault should have tripped a properly installed GFI instantly. It wouldn't, however, trip a conventional circuit breaker.

SOhappy

It did trip the GFI....when I plugged it in to the extension cord the right way. I got tired of the GFI tripping, so I out-dumbed it by plugging it in to the extension cord upside down, leaving the ground pin from the trailer disconnected . I know better now .