Shore power trips house GCFI

[Rockin]

Saturday I plugged the LQ trailer into shore power for the first time. Immediately the GCFI in my garage tripped.

I isolated it down; if I turn off the breaker for the fridge and converter circuit, it won't trip. I turned the fridge off and still the same thing. Then, I plugged into the house bathroom and had the same results. Again, it is a GCFI circuit but is 20amp instead of the garage's 15amps. I didn't think to put it on a non-GCFI circuit but when I took it to the dealer, it worked fine. When I get home tonight, I'll try it on a non-GCFI circuit.

The dealer told me to get an adapter without ground and it would solve this problem. This seems to me to be a dangerous situation. This would make it so any plugged in item in the trailer would not be grounded. It would also mean that if something went to ground, anyone touching the chasis and ground would be electricuted.

I'm guessing this is likely because the converter has the neutral and ground connected which is why the GCFI trips but a non-GCFI circuit works fine. Can anyone verify this? If this is the case, on a non-GCFI circuit, ground in the trailer should still work. Is there a way I can test this? Maybe check continuity between ground and neutral in trailer plugs? Or, would it be between prongs on the shore power plug?

[GBurton]

Hi Rockin
A GFI circuit breaker actually contains two completely different types of protection devices. One is an over current device that is rated in amps, 15 or 20 amps which work like all other circuit breakers. If you try to use more current than the circuit breaker is rated at or there is a short circuit, it will trip. The second is the GFI or Ground Fault Interrupter. A GFI outlet does not provide over current protection that is provided by a normal circuit breaker. A GFI circuit breaker or outlet is normally used where there is the possibility of you touching ground (the earth) and an electrical powered device that uses the normal 110 outlets for power, not battery powered.

How does a GFI device work? The GFI outlet or circuit beaker provides protection by checking for a difference in the amount of current that is flowing in the "hot" leg as compared to the

[Viking]

Rockin, if you are using an extension cord that you have made possibly the ground and neutral are reversed. Happened to me.

[Viking]

Correction to my last post, the neutral and hot were reversed.

[Rockin]

The research I've done has said the trailer should not have neutral and ground connected. (http://www.phrannie.org/phredex.html) and an article (The 12v side of life)

I have connected to two different non-GCFI circuits and had no problem. I've connected to two GCFI circuits and they do have the problem. It is clear things will work when not connected to a GCFI. My question is if the trailer is wired correctly/safely.

Is it correct to assume that if neutral and ground are connected, a DMM would show continuity across the ground and neutral on the trailer plug?

IF they are connected, should I just plug in on non-GCFI and not worry about it?

[Heartbeat Hauler]

I'm not sure if this will apply to your situation, but I had a similar problem with my bathroom outlet. I could not plug anything into it with out throwing the breaker. I replaced the outlet, the breaker(thinking it was weak)and still no luck. I finally called an electrician and he discovered that my outside outlets were on the same circuit. He checked the outside outlets and water and leaked passed the seals and corroded the outlet into a short. Replaced those outlets and no more problems. Maybe you have a circuit that is corroded and intermittent. :confused: Good luck.
JP

[GBurton]

Hi Rockin

To answer the question,

[ktmracer]

all the above info is correct and helpful. in fact, i went through about ALL of them before i finally found my problem; know what it was? my deep cycle house battery had a short in it!! the battery short was causing a feed back/light voltage short through the converter and tripping my house 30 amp gcfi circuit. sometimes the simple stuff is just easy to overlook.

[Turbine Doc]

Rock,
From your reference to shore power hook up leads me to believe you are former Navy, Coast Guard, or Merchant Marine that correct,? (me too USN former GSM)

If so don't make same mistake I used to make when I started playing with civilian shore land based shore power, hot leg is only 1 side at 115v vs 55v each leg as in marine power; and neut/gnd will be pretty much same potential as each other. But gnd & hot alone will only give about 60v, the neut needs to be carried as well as gnd for full 110-115v.

GFI's are pretty sensitive to load, I had several that could not handle the current draw on a older freezer compressor that would trip the GFI, the problem was low freon but when plugged in to a normal recpt would not trip the main breaker.

If polarity is correct I suspect it is the high amp draw of the trailer load causing the GFIs to trip, especially if you have an inverter to convert 115 Vac to 12 Vdc, I run solar at my camp and have an inverse problem converting 12 to 115 the inverter has a healthy surge load lights can dim.

Try plugging in trailer with all trailer breakers in off then turn on one at a time after connected, this will also help you to isolate if you have an electrical problem happening as individual circuits come on. If it trips after energizing a circuit look for a device with a high amp draw or maybe starting to have a problem.

One more thing to try if you are not doing so already is drive a dedicated ground rod for the trailer when hooking up.

[HowieE]

A common problem with GFI and power supplies, such as your convertor, is the fact that many power supplies have filter caps on the input side to reduce noise that are tied to the frame of the power supply and thus on startup there is a current flow directly to ground and thus the GFI trips.
If you ar egthe type that wants to use a GFI look for a convertor that does not have capacitors on the input side of the circuit.

[markelectric]

Do not ever drive a seperate ground rod for any reason. Ever. If you feel a need for aditional grounding you may want to add a rod but it MUST be attached to the exhisting one. Many times I have seen some weird stuff because of differing potentials between two rods on one service. In each case connecting the extra rod or rods to the main one solved all the problems.
In the case of the tripping GFI the affected circuts may have a bare ground wire touching a nuetral in the outlet box when it was stuffed in. The one breaker at a time may help on that search.