More random GFCI tripping

More random GFCI tripping

Dear Mike,
I have spent many hours online trying to find the answer to my problem. I have tried everything that I have read but still haven’t fixed my problem. I thought maybe if I turned to the expert I might get the answer. Can you please give me something else to try here.

When I plug my 2013 RV into my garage it trips the GFCI outlet in my garage. This has also happened at two different locations (friends’ homes) that I have tried to plug into. I have checked every outlet in the RV with a tester and they all check out wired correctly. I have turned off all the breakers before plugging it in but it still trips the garage GFCI. I have unplugged the fridge and microwave but that didn’t work either. I checked inside the RV panel to see if any ground or neutral was on the same bar but they weren’t. I tried using a 2-prong adapter that does not have the ground prong but that didn’t work either. I don’t know what else to check. It doesn’t trip the regular breaker, just the GFCI button. What may be causing this problem? –Jeff P.

Dear Jeff,
GFCI troubleshooting can be intimidating simply because there can be several contributing factors that are additive. That is, several different appliances can leak a little to the chassis, or one can leak a lot of current to the chassis, but both will have the same effect. I’ll do a quick review of the basic troubleshooting methods, but then introduce another crazy one I don’t believe I’ve written about before.

So first, the simple stuff….

Anything inside of your RV that has a ground plug on it can leak current to the RV’s chassis-ground, and just 6mA (milliamps) of current can trip it. And that’s exactly  how it’s supposed to work. Since this problem can be coming from anywhere, then you must divide and conquer. Start with all circuit breakers in your RV turned off and plug your RV’s shore power cordset into your garage’s GFCI outlet. If it doesn’t trip, then turn on one breaker at a time until it does trip. Then figure out what’s on that circuit and turn off everything on it, then reset the GFCI and try again to isolate what’s making it trip.

Hard to believe that’s the simple solution. But if it still trips the GFCI no matter what is turned on on a particular circuit, then there’s the chance that you have a swapped Ground and Neutral Wire inside your RV somewhere. That’s really hard to find since both are electrically similar. But if they’re swapped somehow, then the GFCI will trip with any load applied, not just a leakage failure like it’s supposed to do.

So here’s how you can find it. Make sure you use a GFCI receptacle for this test since it can be dangerous, and safety first. What you’re going to do is use a ground lift adapter on the shore power cordset where you plug it into your garage GFCI outlet. You should now be able to turn on all the breakers in your RV without the garage GFCI tripping. Now you can plug something like a trouble-light into each of your RV’s receptacles one at a time. If the light comes on, then that particular outlet has the ground and neutral correctly wired. But when  you come to an outlet without the light coming on, then that’s the one that has a swapped ground and neutral wire.

If you do find this, then disconnect all power going into the RV, open up the outlet and inspect the wiring for proper color code, with the white wire going on the white-colored screw on the outlet with the taller slot, the black wire going on the brass screw with the shorter slot, and the green wire going on the green “ground” screw going on the U-shaped slot. Correct the miswiring, put everything back together, and reconnect to the GFCI outlet without the ground-lift adapter. If it works, then you’re in business.

The third possible scenario is getting really complicated, but it’s possible that insulation in your wiring has broken down or failed somewhere and allowed a ground wire to contact the metal frame of your RV. This could be something simple like the ground wire inside of an outlet box that may have been stripped back too far and is making contact with the frame. That extra contact point can be enough to trip a GFCI. But more on figuring out that problem later. 

Let’s play safe out there….

 

Mike Sokol is an electrical and professional sound expert with 40 years in the industry. Visit NoShockZone.org for more electrical safety tips. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.

##RVT843

 

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10 thoughts on “More random GFCI tripping

  1. Tim

    When my 2006 trailer was new it would trip a GFCI when connected. After doing the usual testing without success I got creative.

    I removed all neutrals and grounds from the trailer panel. I then put them back one circuit at a time til I found the defective circuit. The final result was finding that a staple had pinched the romex in the circuit for the air conditioner. The staple was conducting between the ground and neutral but not the hot thus tripping any GFCI protected source.

    1. Mike Sokol

      That’s a great way to test. You can also measure the resistance between the neutral and ground wires going into your RV, which should measure at least a few 100K ohms. I’m working on a video of this method which will fully explain the process.

  2. Jeff Preeshl

    None of this solved my problem. The gfci trips right when I plug in my rv when everything is off. It still trips it when I used the ground-lift adaptor.

  3. Mike Sokol

    Another EE from a different forum emailed me today about his findings of a fried water heater element can create a shunt between the neutral line and frame ground of the water heater. He’s absolutely correct about that possibility. I’ll draw up a schematic of how that works and a few ways to measure it in a future article.

  4. Bill Lampkin

    Check your RV cordset for an open neutral wire. Use another cord from the GFCI in your garage to your RV, see if the outlet trips. Most ‘trippy’ GFCI problems are caused by a damaged RV cord endcap.

  5. Irv

    Thanks Mike. Good troubleshooting tips that I wouldn’t have thought of. Especially the one using the ground-lift-adaptor.

  6. Don & Nancy Schneider

    Mike, I now have 3 outlets on the GFCI circuit that have no power due to an Open Ground – according to my 3 prong outlet tester. The bathroom outlet is where the GFCI reset is located.
    The outlets failed 1 at a time over 3 months or so. How do I find the Open Ground and fix it?

    Thanks in advance

    1. Mike Sokol

      I think a visual inspection will reveal a swapped neutral and ground wires in one of the outlets feeding that branch circuit. After shutting off all power, pull the outlets out of their boxes and double-check that the grounds and neutrals are connected correctly. It’s most likely the GFCI outlet that’s feeding the rest of the circuit.

  7. Mike Sokol

    Yes they do. You’re supposed to test GFCI’s monthly, but nobody really does that. And after a few years of vibration and moisture, some of them will trip under any load. If in doubt, replace a suspect unit with a new quality one. The cheap ones lack some of the discriminating circuitry that reduces random tripping.

  8. Cheryl Haupt

    We had the same problem with our motor home. Turns out the GFCI in our garage was bad. Once we replaced that, no more tripping. Apparently they do go bad over time.

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