GFI clicking off when I plug my Camper in????

Anything electric, AC or DC

Postby Arne » Wed Jul 08, 2009 2:00 pm

I had a shed. I insulated it with foil backed insulation, on the inside of the rafters to form ducts to get the heat the the gable fan. The underground wire went into the garage to a gfi. any time I touched the foil and any one of the 3 ceiling lights, the gfi popped... everything was wired correctly, it just could not handle something... after a couple of times, I learned not to do that. The foil backed insulation did not touch any ground as it was inside the shed. there was just something it did not like. and the foil backed insulation did not come in contact with the light fixtures...

I gave up on it and just didn't touch both again.
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Postby jeep_bluetj » Wed Jul 08, 2009 2:11 pm

Miriam C. wrote:
GFCI after the panel in the TD to protect all circuits down stream. I left it off my airconditioner.


High load motors can falsly trip a GFI due to inductive/capactive loading. In simplest terms, large motors can have the current gosinta != current goouta during the start phase. This can nuciance trip a GFI.

Miriam C. wrote:With no grounded drop cord you have no ground. With no ground the GFCI will trip. KISS try the cord first


Nopey nope nope nope. Larwyn is right. GFI's work the exact same way if there IS a ground, or if there isn't. (A GFI is the only NEC approved way to retrofit older 2-wire circuits to allow 3 wire recepts without running a ground wire.) GFI's don't ever need upstream or downstream grounds.

All a GFI does is measure the difference between current out and current in. (Hot and neutral, nothing is measured against ground)

If gosouta == gosinta, everything is great, nobodies getting fried today.

If gosouta <> gosinta, the GFI trips. Why? Cause that current is going somewhere. Maybe that current is shorted off because hot is shorted to the grounded frame of the trailer. Or maybe its going through somebody, or thier beloved dog/cat/spouse/whatever you don't want toasty. The GFI really doesn't know, it just knows that if _any_ current is "lost", that's a bad thing.

But it doesn't really have to do with the ground wire in the cord, it's just generic ground (like the actual driveway).
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Postby Miriam C. » Wed Jul 08, 2009 4:22 pm

Miriam C. wrote::? Ok everyone reread your posts. :lol:

GFCI after the panel in the TD to protect all circuits down stream. I left it off my airconditioner.

With no grounded drop cord you have no ground. With no ground the GFCI will trip. KISS try the cord first

Worry about screws if something if that fails. And get some wood behind that panel. :thumbsup:


:oops: Obviously speaking to myself. :shock: I apologize as I have run two sentences together and OMG.

Should read "with no grounded drop cord you have no real ground. With no ground the panel should trip when a short happens and the GFCI may or may not trip. Depends.

I am wondering why your breaker didn't trip when you got shocked.

The truth is we are guessing and you have been shocked.
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Postby Miriam C. » Wed Jul 08, 2009 4:41 pm

I have separated this so you can quote it and if you would please answer some questions.

1.
Tryed another cord plugged to my RV cord, it tripped.


What is "your RV cord?"

Where is your GFCI that keeps tripping?

2.
It will still trip the GFI with the breakers cut off in the box,


Does it work on a normal receptacle? Do you have power in the trailer?

3.
My box is grounded to the frame. The frame and wall supports are all metal and the box is screwed to a metal wall support.


UNPLUG IT FIRST
Is there the slightest chance you have the screws attaching the panel touching a live wire or a neutral wire. Look closely at your wires. Not always a lot of room in there.

Do you have power in the trailer before it trips?
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Postby jeep_bluetj » Wed Jul 08, 2009 5:51 pm

Miriam C. wrote:I am wondering why your breaker didn't trip when you got shocked.



Not enough current. Breakers protect ONLY for overcurrent. So to pop a breaker, you'll need to be pulling over the rating of a breaker. In this case, I'd guess the breaker was 15A or 20A. If 15 amps were flowing through madprinter, he would definitely not be "pinin for the fijords," he'd be an ex-printer. Really, to get this much current flowing through a human at 115v, your resistance needs to be _really_ low -- like standing in a salt-water bathtub with a golfclub and a tinfoil hat low.


There IS a short/partial short from hot to _something_. That something is likely the trailer frame. A bit of sleuthing with an ohmmeter will find it. I'll bet it's in your cable -- i.e. the GFI trips, but all breakers in the trailer are off, it's between the plug and the breakers.
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Postby Miriam C. » Wed Jul 08, 2009 6:10 pm

jeep_bluetj wrote:
Miriam C. wrote:I am wondering why your breaker didn't trip when you got shocked.



Not enough current. Breakers protect ONLY for overcurrent. So to pop a breaker, you'll need to be pulling over the rating of a breaker. In this case, I'd guess the breaker was 15A or 20A. If 15 amps were flowing through madprinter, he would definitely not be "pinin for the fijords," he'd be an ex-printer. Really, to get this much current flowing through a human at 115v, your resistance needs to be _really_ low -- like standing in a salt-water bathtub with a golfclub and a tinfoil hat low.


There IS a short/partial short from hot to _something_. That something is likely the trailer frame. A bit of sleuthing with an ohmmeter will find it. I'll bet it's in your cable -- i.e. the GFI trips, but all breakers in the trailer are off, it's between the plug and the breakers.


:thinking: If you ask enough questions instead of guessing you will ask how he got shocked if the GFCI was tripping and shutting off the current when first plugged up. My questions need to be answered by Madprinter before you can be sure. ;)
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Postby jeep_bluetj » Wed Jul 08, 2009 7:19 pm

Indeed, before I can be sure. That's correct....

But for fun: )....

I just reread enough to guess that the question of "why didn't the breaker trip" was more likely "why didn't the GFI trip?".

And _that_ is indeed a superduper question. 'Cause it sure should have.

I'll even guess sommore :) -- I'll guess it wasn't plugged into a GFI during the shocking event. Because if it was, you can't get shocked. (To be precice, not shocked with a working and correctly wired GFI.. All bets are off for a broken one)

If my speculation is true, this trailer should not be plugged in before it's repaired. This is not a safe situation.

Based on the OP, and the questions beyond that, I'm putting $5 down on::

Hot lead from the inlet cable OR the hot bus in the breakerbox got a screw/nail/abrasion etc in it and is shorted to the trailer frame.


But of course, I'm rampantly speculating. I'm bored at work... :) Better speculating about GFI's and trailers than other stuff.

Me? I'd Unplug the trailer, and measure resistance from the hot lead on the input to ground, neutral, the trailer frame, etc.. All should be infinate. But one of them likely won't be. And tracing _that_ back will find the problem.

If a GFI trips, with no lpossible oad at all on any downstream circuit, it's always some path for current from hot to "somewhere else" -- like the grounded conductor, or the actual earth.
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Postby madprinter » Wed Jul 08, 2009 8:09 pm

;) Finally found it!!
I don't know how I did it, well maybe it was other self, but I made a major boo boo when I attached my neutral input wire to my box.
I put the wire on the back side of the lug screw, between the box wall and the plastic insulating panel. When I screwed the lug up tight it pushed against the plastic panel and felt secure. It must have been curved back enough to touch the lug some, giving me power. After a few power ups, it must have made contact thru the paint and started the GFI to tripping.
I was really lucky the ground was'nt wet are I would have been the "Ex Printer" as stated. God must be protecting me. I'm off on my first trip this weekend to the Caddo river in Glenwood Arkansas. We'd love to have some fellow members join us. Relaxing, canoeing and getting sunburned.Sounds fun. Thanks to all for the input. :thumbsup: William
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Postby wlooper89 » Wed Jul 08, 2009 10:43 pm

Miriam C. wrote: :lol: I have just got to ask why? Seriously I really would love to know. I stayed at the motel 6 :) :lol:


A good one Miriam! :D Since the GFCI is looking only at things on the load side or downstream, I suggest the sooner the better in trailer wiring, as soon as possible after the power inlet. Especially if the electrical compartment is metal. One could install it after the circuit breaker(s). But that leaves a little more chance for a short to ground that is not protected by the GFCI.

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Postby wlooper89 » Wed Jul 08, 2009 10:51 pm

madprinter wrote:;) Finally found it!!
I don't know how I did it, well maybe it was other self, but I made a major boo boo when I attached my neutral input wire to my box.
I put the wire on the back side of the lug screw, between the box wall and the plastic insulating panel. When I screwed the lug up tight it pushed against the plastic panel and felt secure. It must have been curved back enough to touch the lug some, giving me power. After a few power ups, it must have made contact thru the paint and started the GFI to tripping.
I was really lucky the ground was'nt wet are I would have been the "Ex Printer" as stated. God must be protecting me. I'm off on my first trip this weekend to the Caddo river in Glenwood Arkansas. We'd love to have some fellow members join us. Relaxing, canoeing and getting sunburned.Sounds fun. Thanks to all for the input. :thumbsup: William


Congratulations on finding the problem! That is a relief to a lot of us. It is interesting it was the neutral connection causing the problem. I believe it can be the neutral wire as well a the hot. Have a great trip!

Bill
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Postby Miriam C. » Wed Jul 08, 2009 11:12 pm

wlooper89 wrote:
Miriam C. wrote: :lol: I have just got to ask why? Seriously I really would love to know. I stayed at the motel 6 :) :lol:


A good one Miriam! :D Since the GFCI is looking only at things on the load side or downstream, I suggest the sooner the better in trailer wiring, as soon as possible after the power inlet. Especially if the electrical compartment is metal. One could install it after the circuit breaker(s). But that leaves a little more chance for a short to ground that is not protected by the GFCI.

Bill


:thinking: Yeah buttttttttttt the air conditioner.......If you put it on the incoming side of the circuit breaker it "may" trip a lot. But I get the concept. We have a few who did not do breakers and they do have a GFCI immediately after the inlet.
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Postby Miriam C. » Wed Jul 08, 2009 11:13 pm

wlooper89 wrote:
madprinter wrote:;) Finally found it!!
I don't know how I did it, well maybe it was other self, but I made a major boo boo when I attached my neutral input wire to my box.
I put the wire on the back side of the lug screw, between the box wall and the plastic insulating panel. When I screwed the lug up tight it pushed against the plastic panel and felt secure. It must have been curved back enough to touch the lug some, giving me power. After a few power ups, it must have made contact thru the paint and started the GFI to tripping.
I was really lucky the ground was'nt wet are I would have been the "Ex Printer" as stated. God must be protecting me. I'm off on my first trip this weekend to the Caddo river in Glenwood Arkansas. We'd love to have some fellow members join us. Relaxing, canoeing and getting sunburned.Sounds fun. Thanks to all for the input. :thumbsup: William


Congratulations on finding the problem! That is a relief to a lot of us. Have a great trip!

Bill


:applause: Yep have a great trip. If it was closer we would join you. :thumbsup:
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Postby wlooper89 » Wed Jul 08, 2009 11:26 pm

Miriam C. wrote: :thinking: Yeah buttttttttttt the air conditioner.......If you put it on the incoming side of the circuit breaker it "may" trip a lot. But I get the concept. We have a few who did not do breakers and they do have a GFCI immediately after the inlet.


That is a good question. I think the GFCI should not trip from a high load. It is only looking for a small difference between hot and neutral amp draw. Normally even with a high load the hot and neutral amps will be the same. In a perfect world that is. ;) In a house the breakers come first, some of them may be combination GFCI and breakers, as for the garage. I put the GFCI first in my trailer. Probably either way is good.

To choose between GFCI and circuit breaker I would go with the GFCI for safety. The campground power pedestal has a circuit breaker. But I used both, a GFCI after the power inlet and then circuit breakers.

Bill
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Postby Larwyn » Thu Jul 09, 2009 7:08 am

madprinter wrote:;) Finally found it!!
I don't know how I did it, well maybe it was other self, but I made a major boo boo when I attached my neutral input wire to my box.
I put the wire on the back side of the lug screw, between the box wall and the plastic insulating panel. When I screwed the lug up tight it pushed against the plastic panel and felt secure. It must have been curved back enough to touch the lug some, giving me power. After a few power ups, it must have made contact thru the paint and started the GFI to tripping.
I was really lucky the ground was'nt wet are I would have been the "Ex Printer" as stated. God must be protecting me. I'm off on my first trip this weekend to the Caddo river in Glenwood Arkansas. We'd love to have some fellow members join us. Relaxing, canoeing and getting sunburned.Sounds fun. Thanks to all for the input. :thumbsup: William


I believe that just might qualify as a "sneak circuit". Glad you found it, they can be a real challenge as they do not show up on any drawings.... :lol: :thumbsup:
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Postby wlooper89 » Thu Jul 09, 2009 3:06 pm

Hope my earlier response about GFCI location made a little bit of sense. I have been very much trying to learn as I built the trailer electrical. My first GFCI was mounted back at the taillight area ahead of the four trailer outlets. Then it dawned on me that my electrical compartment, a metal tongue box, and the trailer frame were not protected from ground fault. Perhaps now I have gone to the other extreme by putting the GFCI first thing after the power inlet. In the beginning I did not realize the GFCI is only looking at things on the load side or downstream from its location in the trailer electrical. But now I am fully trained by staying at the Holiday Inn Express. 8) :lol:

Bill
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