GFCI outlets tripping on house when I plug in my trailer????

When I got my 2008 coachmen adrenaline blast 150 toy hauler a couple weeks ago, I brought it home and plugged it in to a standard 15 or 20amp wall outlet via a pigtail and extension cord. I know this wasn't ideal, but I half expected it to trip a breaker on the house so I could find which breaker it'd trip. To my surprise it worked fine even as I cycled the AC on.

After hanging out for a few minutes I powered everything down and left it plugged into garage. After batteries were nearly full I unplugged it.

Now two weeks later, if I plug it in using the EXACT same set up just to charge the onboard batteries- it instantly trips the gfci on the house. Tried a different one on a different gfci circuit and same result. No switches, lights, or appliances are on. The only changes I can think of is i moved the trailer over about 1 foot in the driveway and we have gotten a lot of rain (raining when i did this but the plugs were all in the garage) and my batteries show 75% charge. 

I've done some searching, but the several treads similar to this the RV/trailer always tripped the outlets. Mine worked fine one day then nothing. I was going to get one of those 3-light circuit testers you plug into an outlet, but if power isn't going to the outlet, I don't think it'll work. I also read you can use an ohm meter on the main plug, but with the batteries hooked up I fear the circuit may have voltage.

Any suggestions???  I'm camping at a place with a hook up for the first time this weekend and am afraid I have a serious electrical issue. Please help!

First welcome to the forum.
You said you had a lot of rain. I would unplug the extension cord and change it with another one. I would also remove the adapter that the extension cord is plugged into at the RV. Water may have penetrated that adapter.
Give things a chance to dry out. Do you have 30 Amp or 50 Amp?

Moisture can get into outlets, both on the RV and the extension cord connections, potentially causing a ground fault. You might try applying a hair dryer to the Rv's exterior outlets and wherever there are shore power cord connections, including extensions and adapters.

A ground fault is a short from either a hot wire or a neutral to the ground wire or surrounding metal. It doesn't have to be big sparks - a tiny, tiny trickle is enough to trip a GFCI.

Since it is a garage outlet, Im assuming it is a GFCI?  That has happened to me on occasion.  Never figured out why, maybe moisture, maybe dirty pin on the plug.  Clean the pins on the plug and try again.

Rene T said:

First welcome to the forum.
You said you had a lot of rain. I would unplug the extension cord and change it with another one. I would also remove the adapter that the extension cord is plugged into at the RV. Water may have penetrated that adapter.
Give things a chance to dry out. Do you have 30 Amp or 50 Amp?

Click to expand...

Thanks. Camper is 30amp. I have a 30amp rv extension cord to the dog bone adapter, I then tried with a regular heavy duty extension cord for my electric lawn mower which was dry and it blew as well. Both worked in the past. Being new to this, I don't even know how/where the camper plug attaches to the camper. It just coils into a hole on the side. The cover that goes over it certainly does not seem well sealed. I'll see if I can find that end and try to disconnect and dry it off.

Yes, the garage plug is gfci. That's what trips. The breaker in the box does not.

The most likely culprit is an exterior wall outlet on the RV itself.  The chance of moisture where the shore cord is hard-wired to the trailer is slim.

I suggested moisture because the problem is new and you mentioned rain, but the rain may be coincidence. It is entirely possible that a strand of wire escaped a connector and touches a ground, in which case you just have to hunt for it. Rvs are subject to vibration and twisting as you travel and when you level, so wire connections tend to loosen over time.

Gary RVer Emeritus said:

The most likely culprit is an exterior wall outlet on the RV itself.  The chance of moisture where the shore cord is hard-wired to the trailer is slim.

I suggested moisture because the problem is new and you mentioned rain, but the rain may be coincidence. It is entirely possible that a strand of wire escaped a connector and touches a ground, in which case you just have to hunt for it. Rvs are subject to vibration and twisting as you travel and when you level, so wire connections tend to loosen over time.

Click to expand...

Thanks. I'll check that.  Not sure how I'll get it dry since it's still dumping rain or how I'll keep power camping since its supposed to rain the whole weekend. I may just have to wait until it's dry. If it is the outside outlet, will it blow fuses on my truck when I'm hooked up?  I do have one exterior light missing a cover too, but I'd think with the switch off it shouldn't be that.

Got some time to mess with it after work.  I shut every breaker off and the charger to the batteries and it didn't pop! So I switched each switch on one at a time with the charger last, and now it's working fine.  If I unplug and replug, it trips.  Is that normal? Should I be doing this switch thing every time?

Only other concerning thing is my trimetric showed drawing 30A to the batteries out of my 15 or 20A wall outlet (still don't know because breaker hasn't popped on house but I am leaning toward 15A).  It dropped pretty quick to 22A where it sits now- still working.  That's concerning.

When I use a 110 outlet at my house while the coach is out front for loading I have the same problem.

What I do now is...go to my main breaker in the coach, two breakers tied together, and shut it off.

I then plug in my extension cord to the house outlet and then turn the main breaker in the coach back on and all is fine.

If it is the outside outlet, will it blow fuses on my truck when I'm hooked up?

Click to expand...

The outside 120v outlet(s) have nothing to do with your truck when towing. Don't mix 12vdc circuits questions with your 120v circuit GFCI problem. They are entirely different and isolated from each other.

Only other concerning thing is my trimetric showed drawing 30A to the batteries out of my 15 or 20A wall outlet (still don't know because breaker hasn't popped on house but I am leaning toward 15A).  It dropped pretty quick to 22A where it sits now- still working.  That's concerning.

Click to expand...

Again, you are confusing AC with DC.  The amps flowing into your batteries from the charger have only an indirect relation to the shore power amps. The charger draws power from the 120v shore source to produce DC amps for charging, but not on a one-for-one basis. The charger draws  1 amp from the shore source for [roughly] every 9 amps it feeds to to the batteries. A steady 22A into the batteries indicate they needed charging. If it doesn't taper off to near zero within 3-4 hours, I would be concerned about the condition of the batteries.

donn said:

Since it is a garage outlet, Im assuming it is a GFCI?  That has happened to me on occasion.  Never figured out why, maybe moisture, maybe dirty pin on the plug.  Clean the pins on the plug and try again.

Click to expand...

Mine has done  that a few times.  I have a refrigerator in the garage and if I am running AC in the coach (on 20 amp setting) and the fridge compressor kicks on, either the CB will pop or the GFCI will trip.  Never happens enough to worry about it but I do keep an eye on it quite a bit.

Bill

The GFCI has nothing to do with the amp load - that's what the breaker is for.

Gary RVer Emeritus said:

The GFCI has nothing to do with the amp load - that's what the breaker is for.

Click to expand...

Bad phrasing on my part.  The GFCI happens for a different reason than the fridge compressor coming on but it usually is an unknown cause which does not recur when you reset the GFCI - at least in my case.

I do know that GFCI outlets are not supposed to be used in series, which would be the case plugging in to a GF outlet in your house and having GF outlets in your camper. I have had this same thing happen before when plugged in to a GF outlet at a friend's house, I believe the answer is a non GF outlet installed in your house. You will note that campground outlets are not GF, which I believe is for this reason.

I noticed the same thing.  When I plugged the FW into a GFCI circuit it blew the circuit every time. I don't know if it was to much of a draw or what. I then plugged it into a  110v 30amp circuit that I use for my welder and had no problem.  Since then I wired a 50 amp to an outside post  where I park the camper.  I have also noted that GFCI outlets seem to get weaker as time goes by and have had to replace them some times.

Im sure someone will give me trouble for saying, but just plug into the house with a cord with the ground removed. My backhoe used to blow the gfi every time if I plugged in the block heater. Same thing with my friends motorhome if he came to visit. Would trip the gfi. If there is no ground on the plug, there is no way for the gfi to trip. I work in construction and am required to have gfi plugs for our work. They are a PITA. I have seen cord ends fall in the lake and the gfi not trip. Next time it rains one drop and the darn things are tripping.

I do know that GFCI outlets are not supposed to be used in series

Click to expand...

That's a myth. There is absolutely no reason for not using GFCI in series.

You will note that campground outlets are not GF, which I believe is for this reason.

Click to expand...

That's not it. For cost reasons, campgrounds install GFCI outlets or GFCI breakers only where the electrical code specifically requires them.

If there is no ground on the plug, there is no way for the gfi to trip.

Click to expand...

That is certainly true, but that only eliminates detection of the fault, not the fault itself. You might also want to disconnect the CO and LP gas detectors and eliminate those alarm nuisances as well.

I have seen the problem with ground faults in series several times, one of which was corrected at a friend's house by a licensed electrician and solved the problem. A previous "electrician" had indeed put two ground faults in series, and it would not always trip but often trip.  If it is a myth, it is a myth based on fact. As delicately balanced as GFCI units are, it does not take much to trip the unit.
GFCIs are basically an electrical balancing act, and one too many on the tightrope can cause problems as described.

If ground fault circuits were necessary or logical on campground receptacles they would be required by the code, which is based on safety, not the campground owners expense.

Is it possible that the problem for the OP is that RVs have floating grounds so that they can cause the GFI in the garage to occasionally think that there is a ground fault?

Is the reason that RV's do not have GFI outlets because they work with a floating ground?

If GFIs are so important  (and required) in homes why are there no problems with people getting severe shocks in their RVs?

Perhaps those with more experience at this can educate me on this.

By the way, while it does work, I try to never install 2 GFIs in series because when the upstream one trips the downstream one appears to have also tripped and it drives you nuts to figure out the source of the problem if you forget that 2 are in series.  Having two in series adds no particular value.

Is the reason that RV's do not have GFI outlets because they work with a floating ground?

Click to expand...

I think you will find that ALL RV's have at least one ground fault equipped outlet and perhaps several more regular outlets protected by that circuit. (Up to 6 non-ground fault equipped outlets can be daisy-chained to one GFCI outlet and be protected. GFCI protection can also be provided through a GFCI equipped circuit breaker in some cases.

Outlets normally protected in an RV by a GFCI outlet are the bathroom counter, the kitchen counter and the patio outlet with others possible as well.