No Electricity - where to start troubleshooting?

[cobbfoodie]

Our 1976 Sovereign, Melissa, she is in rehab, suddenly keeps tripping out the GFI breaker when docked. We are busy building a new home and we have it connected to the temporary construction power supply using a dogbone and about a 75 ft extension cable. I realize this is not ideal because the breaker at the temporary panel is probably only 15 or 20 amp, but the fact is it was working for at least a couple of months running the refrigerator and all the outlets (NOT the AC). Suddenly one day it kicks the breaker at the temporary panel immediately when I try to plug it in. During this rehab time, we have camped several times no problem. We have removed all gas appliances and gas lines. Nothing is plugged in except I guess the refrigerator must be hot wired to the panel?

Any ideas where to start looking? Thanks everyone!

[TG Twinkie]

If the GFI is on the pedestal and you are using an extension cord.
It could be the extension cord.
Have you tried disconnecting the extension cord from the coach, then plugging the extension cord into the pedestal to see if it trips the GFI?

[uncle_bob]

Hi

If you are on a construction site, first guess is that the power feed is miss wired. Get that part checked before you go crazy about the RV.

Bob

[TG Twinkie]

If the problem was/is with the pedestal it would have been there since day one.
Apparently this is a recent change.
It could be the insulation of the extension cord is breaking down due to exposure to the elements.

[uncle_bob]

Hi

Again, if it's a construction site, stuff changes without a lot of formal control. I'd check the pedestal .... It also could be something as simple as a lug that didn't get as tight as it should be.

Bob

[SuzyHomemakr]

Have you checked your voltage in the trailer?

I would have a tendency to think that it's either the extension cord or the GCFI plug itself. Both of those things go bad when used heavily. You could have easily fried a connection in the extension cord, plugging and unplugging it.

[gator.bigfoot]

Check out this article on ground faults.

http://www.fluke.com/fluke/uses/comu...ng-ghost-trips

One place to start is turn off all breakers in the trailer and then plug in. Also, make sure that there is nothing wrong with the GFI itself. Plug into the outlet without the trailer. I have seen more than one defective GFI.

If you determine that the trailer trips the GFI with no load then you definitely have an issue with the trailer. If everything is ok then turn on one breaker at a time and see what happens.

[VaTravelers]

I have had occasional GFCI breakers on my house and have driven myself crazy trying to figure out why an system that has been operating fine for years all of a sudden isn't. Every time this pops up is turns out to be a weak GFCI breaker. I'd check that first - make it easy on yourself!

[JohnTF]

1st buy a min. quality multimeter around $50 and up , do not bother with too cheap / chineeze / garbage - you need to learn - not outsmart cheap tools .
A knowledgable technician should be able to work with cheap tools , but a newbe shouldn't .
If your into religion - use the old - learn how to fish & make bread - not just give you bread & fish .

[TheGreatleys]

Have you been doing any electrical work in the trailer? All these other replies are good, but I'm going to suggest the possibility that the GFCI is functioning as designed, and you have a ground fault somewhere in your trailer.

This means that your AC neutral (white) wire is shorted to ground somewhere in your trailer. That could mean you tied the AC neutral and ground together somewhere on purpose, or just that the AC neutral is touching the skin somewhere.

Note that if you have a neutral wire shorted to ground, turning the breaker off will not help. The breaker switches the hot side, not the neutral side. If a neutral wire is shorted to ground, the breaker's position will have no effect.

To test this, get your multimeter and test for continuity between any AC negative wire in your trailer and a ground wire or the shell. If you have continuity, you have a ground fault, and your GFCI is doing it's job.

[guskmg]

I have had problems when there are two GFs in the same circuit. I think one confuses the other.
guskmg

[68 TWind]

Check the outside 120v outlet on the trailer. I was tripping the GFCI breaker on occasion before I installed a dedicated 30amp plug. I had a good extension cord and never ran the AC on it. It would work sometimes and at other times trip the GFCI. On a tip from a fellow forum member I pulled the outside 120v AC box. This inside was wet with lots of corrosion. A new receptacle and new box and gasket fixed the GFCI problem. After finding the problem I realized that most of the time it would act up was after rain storms, hind sight is 20-20...

[cobbfoodie]

My neighbor tested each breaker inside the trailer AC panel. Sure enough the neutral is shorted with ground. Now just to find where? Maybe replace the main AC cable coming into the breaker panel? It is probably over 40 years old, The dog bone was fine.
Thanks for the help!

[cobbfoodie]

Aaah! I will check that as well because it is located on the outside somewhere below the stove exhaust fan I think, where we had water leaking in.
Thank you!

[uncle_bob]

Hi

If you *know* there is a neutral short, pull the power and check it with the ohms function on a multimeter. Assuming the meter reads the short, you can isolate it by lifting each neutral at the panel in the trailer. The one you lift that makes the meter go to open circuit is likely the one with the problem......

Working out which neutral is which is a matter of following it back to where it cones into the box and noting which black wire it pairs with in the Romex. Then follow that black wire to a breaker ....

Bob