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trouble resetting gfi

My ftx has a circuit breaker-type gfi that will sometimes trip. When it does, I am unable to reset it if there is any 12 volt house load at all, it trips again right away. If I shed all 12 volt house loads I can then reset it. Anybody experienced this? This will happen whether on shore or generator power.


Should I be looking at the house charger, or do I have a flaky gfi breaker after 30 years?

Thanks n advance
1980 FTX 38 RED

Re: trouble resetting gfi

Reply #1 –
Are you saying that this GFI is in a circuit breaker panel?  GFI's are made for panels and outlets.  Are all the connections tight?  Anyway sounds like the easiest thing to do would be to replace it as a start to fixing the problem.  If it is the type that is in a duplex outlet it is most likely rated at 20 amps as there are usually several more outlets downstream.  Many folks may buy the cheaper 15 amp model not realizing the difference.  GFI's do fail occasionally.
Jerry Whiteaker former owner 96 U270  36' #4831 Austin,TX-Owner Mods LCD TV w/front cabinet rebuild - LCD TV bedroom - Dual Central AC, either can cool coach w 30 amp - Skylights at roof AC openings - Drop ceiling for ducting of AC - Shower skylight white gelcoat/wood/epoxy frame - Air Springs/Shocks replaced - 2014 CRV - 8K Home Solar - Chevy Volt

Re: trouble resetting gfi

Reply #2 –
Any moisture around any AC outlets that are on the GFI circuit will cause it to trip.  Once at MOT, a well meaning salesman washed my coach including the water compartments (both), they have duplex outlets, and they got very wet from the pressure washer, and yup, we had a real experience drying all the outlets so the GFI would stay ON.
Just my experience

Re: trouble resetting gfi

Reply #3 –
I wonder if it's sharing a (bad) ground connection with some of the 12v loads?  If the ground is bad, 12v current through the ground might  raise the ground above the neutral 115v connection and cause it to trip/not reset.  (Another possibility is the same scenario but just hypersensitive GFI, which you would need to replace.) 

Possible test:  Turn off all 115v sources (including inverter) and 12v loads, then measure voltage between the protective ground that the GFI is tied to (in the panel or box) and the neutral leg of the 115v supply in the panel or box.  Repeat with only the 12V loads on and see if there is a voltage.  If there is a voltage, there is probably enough current flow to trigger the GFI (takes only ~5 ma or so.)

Dave and Nancy
1999/2013 U270 36' Xtreme
Motorcade # 16774
2013 Subaru Outback
KD0NIM

Re: trouble resetting gfi

Reply #4 –
My thoughts are along the lines of Dave K.  Maybe you can narrow down the 12 volt culprit by pulling all your 12 volt fuses (panel mounted on bed base) and replacing one by one until the GFI trips.  My understanding of GFI's is that it measures the hot and neutral currents and if they aren't  equal (and opposite) within a small amount it trips.  Maybe there's a 12 volt device that is getting it's return ground via an AC neutral line that's on the GFI circuit.

I don't think the charger could be the problem.  It's not powered through the GFI. (but verify this in case it was changed by someone over the years)
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: trouble resetting gfi

Reply #5 –
Thanks you guys!

Great community here!
1980 FTX 38 RED

Re: trouble resetting gfi

Reply #6 –
The charger IS powered through the gfi, and there's quite a bit of forum chat in the other rv forums abut this particular model charger tripping the gfi if so wired (intelipower 9200 series). Intelipower claims that their unit isn't the problem so I may also have a weak breaker. In my searching I did discover that the 120 neutral was not bonded to the main box case (there was about a 5 volt difference between it and ground) so I cleaned that up, and today will be moving the charger to one of the AC or other available circuits. Anyway, thanks for all your input and a special thanks to Jimmy in Oklahoma who is sending me his new and unused gfi breaker. Great community!
1980 FTX 38 RED

Re: trouble resetting gfi

Reply #7 –
Rick,
The neutral and ground in an RV electrical loadcenter are NOT to be bonded together. The netural is not bonded to the loadcenter only the ground bar is bonded to the loadcenter all of your grounds are landed on the ground bar and the neturals on the netural bar.
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Bobby & Norma
1992 GV U280
C8.3 Cummins

Re: trouble resetting gfi

Reply #8 –
Quote from: rickricca –
In my searching I did discover that the 120 neutral was not bonded to the main box case (there was about a 5 volt difference between it and ground) so I cleaned that up,

Check "Family Motor Coaching" magazine, May, 2010, page 40, for some excellent explanations about why the neutral should NOT be bonded to ground or the distribution box. It is DIFFERENT from a fixed residence.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: trouble resetting gfi

Reply #9 –
Thank you

I will remove the bonding screw (and search for that article)
1980 FTX 38 RED