GFI Has me totally stumped

[tinbender]

Plugged in the trailer yesterday after it has been down for reinstallation of the interior after a floor replacement. The GFI breaker tripped soon as I flipped it to the on position. There are 5 outlets, using 2 12/2 wires, that run from that breaker. Nothing was plugged into any of these outlets during testing.
After doing much reading of threads on the subject I did the following to try to find out where the problem lies. Today is the 2nd day of trying and still the breaker trips.

Checked outside power inlet wiring, new Marinco inlet installed, it looks good.
Checked wiring of all outlets on the circuit that were disturbed during interior work. Hooked up correctly, no breaks, screws tight, can't see a problem. Removed different outlets from the line and breaker still popped.
Polarity checked and good on outlet from house that supplies power, 20 amp outlet. Polarity in outlets in trailer that are on other circuits check good. Voltage 122.
New Iota converter installed. Removed it from the equation, breaker still popped. Plugged it into a separate outlet with an extension cord containing an inline GFI. It seemed to work fine, didn't trip that one.
Cleaned 120 volt frame ground attachment areas and hardware. Has a new #6 ground coming from breaker panel. 12 volt side has same new ground wire to frame. Combination 120/12volt panel, converter plugs into it also.
Have a molded 30 amp shore cord using a 30 to 15 adapter. Have 2 new adapters, used them both made no difference. Checked to see that none of the neutral wires in the bar are touching any of the ground wires in the bar and that all are tight. Hot wires to breakers tight.
Makes no difference if any of the other breakers are on or not, as soon as I turn on the main 30 amp breaker allowing power to come in the GFI breaker pops. I also replaced the GFI breaker with a regular 20 amp breaker and all was well. While I had it switched, checked polarity on outlets on GFI line and it checked good, voltage 122. Then I got another new GFI breaker and $44.00 later I'm still at square one. New breaker made no difference.

As long as the GFI breaker is left off you can turn on the other circuits and they operate fine, 120 and 12volt, so far as I can tell the new converter seems to be working.
I read some posts that talked about removing neutral wires to test the system. Don't know exactly how that was done, what to do when, with power without, etc.
Out of ideas and open for input, not sure where to go from here.

Don't think it matters but for the record there is no battery installed right now.

Thanks, TB

[Darkspeed]

Somewhere in your trailer ground is connected to neutral

Look for this thread - 30A to 20A to bypass GFI?

[68 TWind]

Have you checked to see if the outside 120V outlet is dry? I had a problem with the GFI on the outlet that I plugged the trailer into tripping and I checked everything. Finally someone said check the outside outlet. When I pulled the receptacle out it was wet inside due to an old gasket. I understand that this GFI is on the trailer but a wet outlet would do the same in either case.

[garry]

A lot of the GFCI faults are traced to the outside outlet.

From what you have all ready done the only thing I can think of is to disconnect every downstream outlet then restore them one at a time. If the GFCI trips with all downstream disconnected I would suspect an open ground between the GFCI outlet and the main braker box.

[jdalrymple]

As mentioned in another post, an excessively long wire run can cause a GFI trip. If I read your first post correctly, the GFI device in the circuit you are using is a breaker, not the receptacle you are using.

It could be that the total length of the house wiring and the trailer umbilical is long enough to cause some differential on the line and neutral and looks like a fault to the GFI breaker.

[DKB_SATX]

Originally Posted by jdalrymple

As mentioned in another post, an excessively long wire run can cause a GFI trip. If I read your first post correctly, the GFI device in the circuit you are using is a breaker, not the receptacle you are using.

It could be that the total length of the house wiring and the trailer umbilical is long enough to cause some differential on the line and neutral and looks like a fault to the GFI breaker.

I think in this case it's the GFCI breaker installed in the trailer that's tripping.

[tinbender]

Thanks for all the replies so far. Being doing more looking. Frustrating but still at it. To answer a couple questions:
No long cord runs, just the trailer's regular 30 amp twist lock cord and about one foot long 30 to 15 amp adapter going right into the 20 amp house outlet.
Everything was very dry, even outside outlet. When I switched the regular 20 amp breaker and had power to the gfi outlets, the first one I checked for polarity and voltage was the outside outlet. I didn't pull apart every outlet but have at least looked at the wire connections and all appears well. In about the center of the whole line is one where 2 wires come in. It connects from the bath and feeds out to all the rest which includes the outside outlet. When I took out this center one the breaker still popped. So I figured if it popped there then the problem most likely wouldn't be with the ones downstream of it. Did check them all for correct polarity. If I take out the bath outlet then I have no feed at all to anything downstream as it is first off the breaker. Looks like I will have to run a jumper line around the bath outlet to take it out of the picture as it is the first one out of the breaker. I double checked it already to make sure it was hooked up correctly and it appears to be good so looks like pulling it completely out of the circuit is my next step. No more ideas after that. Crossing fingers........ Thanks.

[heslinhotel]

Tinbender,
I had a 78 Sovereign with GFCI problem. It turned out to be in the AC unit. Only found it by disconnecting neutral wires in the breaker box one at a time. As long as white neutral was disconnected all was ok. Don't know if you have AC unit on the TT. I assume you are working on your 72. Electrical problems are very fustrating. Best of luck in your hunt, you seem to be very methodical in trying to trace the problem. Hang in there

[steverino]

I had a similar problem in my house, when a switched light was tied into a GFI circuit. The light was part of a fan assembly over a bathtub, and, by code, needed to be protected by GFI. It was somehow wired such that the neutral took a different path than the switched hot, and would blow the gfi whenever the light was switched on. You probably dont have exactly he same configuration, but look for areas where the neutrals and hots can possibly take a different route to the source. GFI breakers pop when they see a difference of current flowing in the neutral and hot lines.

[vettman]

Are you installing a GFI breaker on the line side side of a
GFCI outlet? Only one GFI device per circuit. I do not understand why two 12-2 conductors are leaving one breaker. One circuit per breaker. Each outlet has a line side (power in) and load side (power out to the next outlet) this is important. Purchase a plug in tester, it is yellow and about five dollars. The lights will indicate ground, incorrect hot connections and other information. Are you sure your wires are not 12-3? black,white, and bare or green (ground).

[tinbender]

First the questions:
I am not installing any gfci breakers that weren't there to begin with. All OEM, as is the 2 12/2 wires that hook up to the hot side of the gfci breaker that is in the 120 volt panel. Nothing had been touched on that breaker before yesterday. there was no need to take the 12/2 off of it when the power panel was removed so I left it just like it was. It is hooked up the way it has always been. One of the wires powers one outlet and that is tied into the GFI system by way of it's hot wire attaching to the breaker. The other 12/2 connects everything else by way of the outlet in the bath. That outlet is a GFI duplex. Bambi has a wet bath so it has to have that.
I am working on my Bambi, she got the new floor and I did all the wiring to put the trailer back together. Meticiously labeled every single wire and connection before it was detached plus about a million photos. Made anything better along the way that was possible. I try to be proactive about things.

Now some progress ????? Very long day but must get this fixed so, unhooked the bath outlet and capped off line and load sides. Hooked up to power, turned on GFI breaker on panel then turned on main 30 amp breaker. NO pop! Shut it all down, connected line and load wires turned on breaker and 30 amp power NO POP. I turned on all the breakers to feed power to the whole thing and it held. While it was holding power I checked all the downstream outlets for power 123 volts. Off to the store in the morning to get a new duplex gfi outlet. Please let this be the fix, I'm tired.

Thanks all, I'll follow up soon as I get the new outlet installed.

[Smokin Camel]

Vettman makes a good point. Be certain the circuit that you are plugged into is not on a GFI. One per circuit unless you want to get into being certain the trip setting on the source outlet is set to a higher tolerance. An example would be a generator with a GFI would probably not be a problem but a household type coul be if two are on the same circuit

[tinbender]

GFI problem fixed. I installed a new outlet and it made no difference, breaker still tripped everytime so..... I removed the 2nd hot from the breaker, yes, it has always been there, and the breaker no longer trips. I don't know why it worked perfectly fine before and not now but it did. All I know is that now every electrical item on the trailer works as it should. And, that is with the GFI panel breaker and a GFI duplex outlet in the wet bath on the LINE side feeding out to the next outlet on the LOAD side. I sure have learned some stuff about the GFI system and how to troubleshoot it!

Passing the electrical test was a major hurdle in the reassembly. She'll be back on the road soon. I think I really like the new converter. During all this testing with power on and loads applied the fan only came on one time. Quite different from the original.


vettman: Purchase a plug in tester, it is yellow and about five dollars

Just for clarification, I have and routinely use a plug in tester to check the outlets. One stays plugged in all the time as well. Cheap insurance.

Thanks again.

[Colin H]

Tinbender,
I've run into similar issues on trailers & it caused a lot of mental anguish Make sure the original polarity light on the trailer is removed from the system. The polarity light is wired with one lead to the ground in the entry box & the other lead to the neutral buss in the box. This minor link between the ground & neutral will cause a GFCI to pop. The polarity light is an antiquated safety device that will cause issues with the modern GFCI safety system.
Have fun,
Colin