Shore Power GFCI Tripping

[fran&frank]

Congratulations, persistence pays off. Be glad you weren't paying someone by the hour to figure this out for you!--Frank

[ITSNO60]

Good job, the multimeter would've pinpointed that as well but your process of elimination did the same thing. Before you replace the air conditioning unit though why don't you test it to see if that fixed the heat pump issue? The heat pump is just the compressor operating with the refrigerant running thru a reversing valve.

[AirstreamJim]

Originally Posted by ITSNO60

Good job, the multimeter would've pinpointed that as well but your process of elimination did the same thing. Before you replace the air conditioning unit though why don't you test it to see if that fixed the heat pump issue? The heat pump is just the compressor operating with the refrigerant running thru a reversing valve.

As soon as I connect the AC wiring I get the GFCI trip. Something is wrong so I'll just get it replaced and have it all worked over at JC.

Jim

[uncle_bob]

Hi

My experience in the past with calling in a pro has been pretty good. I prep the job and have everything accessible before he gets there. I can point him to what I need done and what I've already done. I've never had a bill go over the one hour minimum charge that way. Usually we spend the "extra" 15 to 45 minutes chatting or poking around at things.

Bob

[Mollysdad]

Originally Posted by David F

Have you checked to ensure the neutral bus bar is not shorted to ground?

Wait. Am I missing something? Every power box I've seen, including my home, have the neutral shorted to ground.
"In theory" ground and neutral are the same potential. It's when the GCFI detects a difference in potential to ground that it trips.

Interesting case: My home is old, many outlets don't have a ground. When I tried to add a UPS to my computer, I got a warning that it had no ground, and therefore couldn't protect against spikes. So I created an outlet box with a ground that went outside to a rod pounded 6' into the Earth. Guess what? Still showed a ground fault. I think that distance to the power box created enough resistance to show. Although I still think it will act as a ground.

Originally Posted by uncle_bob

My experience in the past with calling in a pro has been pretty good. I prep the job and have everything accessible before he gets there.

Me too. They have the tools, and don't have the preconceived notions I do. Last time I had a weird problem at home, they traced it to a power strip that had hot and neutral reversed. I never checked polarity on a power strip, I've never seen one miswired. They found it in ten minutes! (of course, it was behind a bookcase so nothing was easy.)
For a hundred bucks, they do a lot.

[Al and Missy]

If I have followed your post correctly, I think the breaker feeding the AC circuit must be bad in addition to your compressor problem. If you had the breakers all turned off and the AC compressor was still causing a ground fault, the AC circuit breaker must be leaking.

A GFCI works by sensing current in the hot and neutral. If there is a difference, indicating that some of the hot side current is leaking to ground (a ground fault) it trips.

Mollysdad, by NEC code, neutral and ground are connected together in a home, but are not supposed to be in an RV, which is considered a load to the home distribution system. Regarding your UPS, it is expecting to see the ground connected to the neutral. Connecting it to a ground rod does not give it what it wants to see. There can and probably will be a substantial potential difference between your house ground point and the added ground rod.



Al

[AirstreamJim]

Originally Posted by Al and Missy

If I have followed your post correctly, I think the breaker feeding the AC circuit must be bad in addition to your compressor problem. If you had the breakers all turned off and the AC compressor was still causing a ground fault, the AC circuit breaker must be leaking.

You make a good point, and I've thought long and hard about this. I went to a local electrical supply house yesterday to replace all of the breakers "just in case". They don't carry the 30/20 tandem that serves as my main (30 amp side) and the AC circuit (20 amp side). I replaced the other two breakers and I'm ordering the 30/20 tandem online. I want to restore my confidence in the AC power system in my Airstream as much as I can.

Jim

[uncle_bob]

Hi

Your neutral and ground are connected at one and only one point. Your ground fault gizmo is *after* that point. It's whole mission in life is to figure out that ground is hooked to something (either neutral or hot). It watches the current flow on neutral and hot. If they are not exactly equal, it trips. Yes, that seems like the hard way to do it For various reasons, it turns out to be the best way.

Bob

[ITSNO60]

Originally Posted by Al and Missy

If I have followed your post correctly, I think the breaker feeding the AC circuit must be bad in addition to your compressor problem. If you had the breakers all turned off and the AC compressor was still causing a ground fault, the AC circuit breaker must be leaking.

Al

If it is the shore power GFCI that is tripping it is not caused by a breaker that is off. The shore power GFCI is protecting the entire RV, and any ground fault existing before or after the trailer panel is giving the return current 2 different paths which is what is tripping the GFCI.

In all my years as an electrician I have never seen or heard of a standard circuit breaker leaking, they are either on or off. I have seen one 2 pole breaker that didn't open on one side once in 28 years. It was a 100 amp main that had not been operated in decades.

One thing I will say, the vast majority of DIY people will almost always blame the circuit breaker/GFCI when it is almost never the case. The circuit breaker/GFCI is just doing it's job.

[AirstreamJim]

Originally Posted by ITSNO60

One thing I will say, the vast majority of DIY people will almost always blame the circuit breaker/GFCI when it is almost never the case. The circuit breaker/GFCI is just doing it's job.

Completely agree. I would never assume the breaker or GFCI is faulty, because if I'm wrong I could be burning my own house (or Airstream) down. That's why I agonized over this--and strung a battery tender out to the driveway for two weeks--instead of just plugging into a non-GFCI outlet and letting the converter take care of the batteries.

Jim

[dsample]

Gcfi tripping
Mine was doing that in AZ when hot. I put a fan on it and it has not happened again

[uncle_bob]

Hi

If the GCFI is overheating, either it is defective or it is overloaded ....(possibly both)


Bob

[dsample]

Thanks Bob,
I have an appointment with the dealership as my trailer is still under warranty so they are gong to fix it. It's definitely not overloaded. I am plugged in to a 50 AMP shore power and the only thing I have plugged in is an apple TV. The apple TV is plugged into the inverter
Have a great weekend
Denise

[Lgebhardt]

I had the same issue with the house GFCI tripping. Even with all breakers off it would trip. Ohm meter showed a connection between ground and neutral bus bars. Removed the neutrals one at a time and traced the fault to the main incoming neutral. Pulled the outside power plug and everything looked fine. I taped it back up and reinstalled and the fault was gone after reinstalling. So I'm back working, but I'm a bit worried since I didn't actually find and fix anything.

Note that it tripped the GFCI even with all breakers off (including the main). I'm guessing the polarity detection in the cord was enough draw to trigger the GFCI.

[uncle_bob]

Hi

If the problem went away after you pulled and re-installed something: That something was bumped up against ground. If it bumped once, it will bump again. Pull it back apart and figure out what it's hitting. No that is not always quick and simple. Often it's not very obvious. Then get the offending "what's it" out of the way. I'd put a good layer of tape over the area as well. It's a *lot* easier to do this in the driveway on a nice day than in the rain at night in the campground ....

Bob

[Rich of SCal]

I am having almost exactly this same problem in my 2012 Sport 16. I have it hooked to an outdoor 20 amp outlet, which is connected to a 30 amp breaker. I have been using this setup for a few years now, without a problem. It even runs my ac. And yes, I have been using a surge protector which takes 2 minutes before it connects the ac power to the AS.

Few days ago, I was in the trailer straightening up from my last beach trip. Was watching tv thru my Appletv box. I went to hook up the power cord to my Tassimo coffee maker, by plugging in the over head outlet which, also powers my small microwave. Upon doing this, my tv went off. I didn't pay much attention at first. Was not using the AC as it was early morning. A few minutes later I tried to restart the tv and discovered I had lost ac power.

Now, ALL of these things had worked fine a couple weeks before, when I was on shore power at the beach for 5 days. Plus I have had ac power up to that morning, and even ran my AC a couple times.

So far I have (after initial trouble shooting):

-replaced the house gfci (it went bad a few years ago and replacing it fixed the problem then)
-replaced both my 30 amp power cord and the 30/15 dongle adapter
-turned off all my trailer breakers...including the one with a GFCI button...there are no other GFCIs in my trailer..in has a shower/toilet combo with no electrical outlets.
-inspected trailer plug power in-point (looks pristine...no signs of arc at all)
-turned off EVERYTHING in the trailer and unplugged ALL ac cords. Completely shut off refrigerator.
-when I connect just the trailer power cord (but not hooked to the trailer) it does not trip. If I connect the cord, ever with everything off and disconnected, it trips instantly. When I connect my gazebo led lights to the same outlet, they work fine.
-visually checked the reverse polarity fuses on the converter. BTW dc from the battery works fine, although I will have to put a charger on it soon.
-I was considering replacing the converter board, but decided to check here first, when I came upon this thread.

So I am going out now to pull the overhead outlet where the micro and coffeemaker were hooked up to see if I find any evidence of shorting.

Was curious if AirstreamJim ever replaced his breakers, and what result?

[Rich of SCal]

Well, using the principle mentioned....check what you were doing just before the problem...

I removed the cover to the outlet where I plugged in my coffee maker. Now, this was an empty wired space, that came with my new airstream in 2012. I since have added an oven, so I put in an outlet and turned on the prewired breaker. As you can see, Airstream did not leave much room. I squeezed in a plastic electrical box to protect the outlet from contact with the outer aluminum...with great difficulty.

Apparently, when I plugged my coffee maker back in the other day, it shifted the outlet just enough for the terminals to make contact with the inside aluminum at the bottom of the picture. Even with the breaker turned off...the GFCI detected the short and would not allow me to reapply ac power!

Actually, I am impressed with the GFCI. It acted before my surge protector, the airstream breakers, or the house breaker could act. Probably saved me from arc damage, at the least.

Well, now I have learned some things, both from reading this thread, as well as the experience. Also, I forgot to mention, that days ago, I ordered a 30 amp breaker and rv hookup box. When it gets here I will be connecting it to my panel so that I have dedicated rv power at the proper 30 amps, with no work around. But glad I found this problem first, since it will not use a GFCI at all. I couldn't even find one above 20 amps. Everything works again, and I have a spare GFCI box, power cable, and adapter plug!

Happy again

[Al and Missy]

On RV parts sites, at ridiculous prices compared to the standard box at home improvement stores, you can find a combination box and outlet designed for RV use that will eliminate the problem you had. I had the converter outlet go bad in my Safari 25. I tried a regular old work box and a shallow old work box but couldn't get either to fit due to the limited space between the inner and outer skins. The RV box went in without a hitch.

I would add that using an outlet without a surrounding box is a code violation and a significant safety hazard.



Al

[rmkrum]

When I put an outlet or switch into a tight spot like that, surrounded by metal, I like to wrap the body of the device and it's terminal screws with a couple layers of quality vinyl electrical tape. Just a little added 'surprise' protection.

Genuine 3M brand seems to stay on there better than the other cheap 'no-name' stuff at the big box home improvement stores...2-3 wraps around, nice and neat, and use your electrician's scissors to cut to length, don't just stretch it to 'pop' it. Stays on better that way.

Yes, I'm a bit obsessive with electrical stuff, but I've still got all my fingers, and no burn scars on my body...

[Rich of SCal]

Yes, I definitely did not want to put it in without a box. Since there was no mounting point I used the faceplate to sandwich the box with outlet to the edges of the inner aluminum. I should have anticipated it slipping. Tape wrap is a good idea, but I also need to figure a way of mounting it so it cannot slide over the aluminum. This is one of those areas where I think Airstream cheaped out. They had it prewired for a microwave, but since I didn't order their overpriced unit they filled the space with a blank, instead of an outlet. Plus, as I said, they didn't put any way of holding the outlet firmly in place.

Before I use this again, got to do some redesigning.