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Stumped on GFCI Circuit Breaker

Posted by sjmaye (My Page) on
Mon, Jan 31, 11 at 13:41

I recently moved in to this house. I have a GFCI circuit breaker in the panel that trips anytime I plug ANY load in to one of the protected outlets. The only thing I can plug in and not trip is is one of those plug in testers to verify wiring is done correctly. Anything else will trip it immediately.

I have tried replacing the GFCI circuit breaker no change. I tracked what I thought were every outlet and all look good. I have disconnected all the outlets except what I thought was the one connected directly to the circuit breaker. No change. Still trips.

This outlet is in the basement almost directly underneath the panel box. The only thing I can think is there must be another defective outlet in between, but I cannot find it.

I am baffled that I cannot find this hidden outlet. Does anyone know an easy way?


Follow-Up Postings:

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RE: Stumped on GFCI Circuit Breaker

Most likely if it trips every time any load is added, you've got one of two problems:

1. The neutral isn't running through the breaker. The GFCI breaker should have the circuit neutral wire connected to the appropriate terminal on the beaker.

2. Either the hot or neutral is touching one from another circuit somewhere.

It's not necessarily a defective outlet. The first thing after assuring the breaker itself is wired properly (and that this isn't part of some MWBC). Then I'd go to the nearest outlet and disconnect the feed to the next outlet and test for tripping... then move on to the next. Divide and conquer.


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RE: Stumped on GFCI Circuit Breaker

It may be a neutral that is shorting to ground in a fixture or receptacle box. This was the case on two house-calls I've done.


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RE: Stumped on GFCI Circuit Breaker

A neutral-to-ground fault should trip as soon as the breaker is closed. I suspect it's what I said earlier.


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RE: Stumped on GFCI Circuit Breaker

"A neutral-to-ground fault should trip as soon as the breaker is closed."

No it wouldn't, it would only trip if there was a load.

Having said that, these are all good suggestions.

What I don't understand is why it DOESN'T trip with the tester. It should if other loads cause a trip. Unless it is doing some weird current splitting that keeps it just below the sensitivity(possible with just a couple LEDs being such a small load maybe?). Either way my bet is one of these three suggestions have it.


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RE: Stumped on GFCI Circuit Breaker

Thank you all for your suggestions. To confirm, I can set the breaker on and all is fine until anything of any load (don't know how much) is put on it. Then it immediately trips. The tester I am using is one commonly available in home stores. It appears to use three little incandescent bulbs, not LEDs. Either way I am guessing the load is under the threshold for tripping.

In the panel box the GFCI breaker has a black wire going to it like all the other breakers, but it also has a white wire built in to it. That white wire leads to a common binding rail where all the white wires for the house lead to. Was it wired correctly?

As far as divide and conquer. That was my plan before. I was making headway going from outlet to outlet making my way back to the panel box. I found what appeared to be the first outlet from the panel box. Connected it up alone and the breaker still tripped like before. Unless that breaker is incorrectly wired I must have another outlet(s) somewhere. Without ripping out drywall I am not sure how I will find it.


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RE: Stumped on GFCI Circuit Breaker

After replying to you guys about the wiring I did a quick search on wiring of GFCI circuit breakers. It looks like the prior homeowner installed the circuit breaker and did not wire it correctly.

According to the generic wiring instructions for a GFCI circuit breaker the black and white wires for that circuit should go to the GFCI breaker and the built-in white wire from the GFCI breaker should go to the neutral rail. In my case the black wire is running the GFCI and the both whites are running to the neutral rail.

I am pulling up wiring for the actual breaker to verify.


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RE: Stumped on GFCI Circuit Breaker- Update

Attached is the wiring diagram from Murray for that GFCI circuit breaker. It DOES appear he had it wired incorrectly.

If I read it right the correct wiring should be:

circuit black---to GFCI
circuit white---to GFCI
GFCI white--- to neutral rail

What I have now:
circuit black---to GFCI
circuit white---to neutral rail
GFCI white--- to neutral rail

Would this cause the problems I am having?

Here is a link that might be useful: Murray MP120GFP Wiring


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RE: Stumped on GFCI Circuit Breaker

A GFCI reads the imbalance between the hot (black) and neutral (white). If your neutral is going straight to the neutral bar there is no way for the GFCI to read the return and it concludes that there is a major fault.

Black and white both go to the GFCI.


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RE: Stumped on GFCI Circuit Breaker

That would definitely cause your problem.

Most likely, the previous owner knew that the circuit required a GFCI (was there a home inspection report?) and just slapped one in without knowing what s/he was doing and then never tested any of the outlets.

The circuit could never have worked with the circuit neutral wired to the panel's neutral bar.


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RE: Stumped on GFCI Circuit Breaker

Yes, there was an inspection report and I bet he did exactly that. Slapped one in without knowing what to do. I have been cleaning up weird wiring things since I moved in. Almost every add-on receptacle has some lame-brained, half-butt thing done. I should not be surprised.

I only blame myself for not doubting the wiring of the original GFCI circuit breaker in the first place.

Thanks for the help.


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RE: Stumped on GFCI Circuit Breaker

Yep, I believe I suggested the breaker being wired wrong as the first thing I'd check.

While it's not your problem, I again take issue with ontario's statement. The way a GFCI detects a neutral to ground fault is that it has a little transformer that couples a small signal on the hot and neutral lines TOGETHER. If the hot touches ground you'd trip a regular breaker, so that's not usually an issue. If the neutral touches ground, the leakage of this small signal will trip the GFCI circuit. It will happen as soon as the breaker is closed. It doesn't require a load. If your GFCI trips as soon as it is closed, it's almost certain that the Neutral is touching ground (or another neutral) downstream somewhere.


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RE: Stumped on GFCI Circuit Breaker

I had a weird situation like what ronnatalie describes. An electrician added a circuit (to separate some stuff from a sort-of overloaded circuit). After bringing the new circuit to the junction box and turning it on, an upstream GFCI on the old circuit tripped and wouldn't reset. He realized right away that neutrals from the two circuits were connected. After tying off the old neutral, everything was fine.


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RE: Stumped on GFCI Circuit Breaker

Ronnatalie- I pointed out that the OP said it only tripped with a load. You dismissed randys (valid)suggestion out of hand and implied that a neutral/ground "fault" would trip the breaker even without a load. Some do and some don't. Most of the ones I see don't. I guess I should have said that instead but I thought your post after Randy was a bit smug sounding and I went off half cocked.


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RE: Stumped on GFCI Circuit Breaker

Guys- I wanted to report back that after wiring the breaker correctly all is well. Many thanks for your help!


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RE: Stumped on GFCI Circuit Breaker

I'm sorry, but it was rightfully discounted. If the protected neutral is connected to another grounded (or grounding) conductor, the GFCI should trip immediately or it's not operating properly. It doesn't require a load of any sort. Now it's possible that the load could have a fault in it, but that would seem not to be the case from his description as he tried a diversity of devices.


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RE: Stumped on GFCI Circuit Breaker

Did you miss the part about some GFCI breakers do and some don't trip without a load if the neutral/grounds are touching? If it was one that doesn't trip, randys' suggestion was valid. Since we don't know what type it is- we can't assume either way. Are you suggesting that Randy is lying when he says he has seen that happen?


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RE: Stumped on GFCI Circuit Breaker

What listed GFCI device (either receptacle or breaker) works in the strange way you invented?


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RE: Stumped on GFCI Circuit Breaker

"Some do and some don't."

The newer ones are required to trip as soon as power is applied to them on neutral ground faults.

This is one of the reasons they will not reset if no power is present at the line terminals.

They are also required to not reset if line & load are reversed (power supplied form load terminals).

Older GFCI equipment did not have these requirements.


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RE: Stumped on GFCI Circuit Breaker

I had a situation a few months ago where something very like what the OP reported was happening. I had a bedroom circuit that the AFCI was tripping on. After some experimenting, I found that I could plug in an alarm clock with an LED display, but any other load caused the breaker to trip after about 1/2 second.

After tearing into the circuit, I found an outlet where the ground wire was touching the neutral screw. The ground had some excess length and it had folded up like an accordian when the outlet was pushed into the box. I cut the excess off and put it back in the box, and the circuit was fine.

This particular circuit is off of a subpanel, and it's a fairly long run (maybe 75' wire length) back to the service entrance. The subpanel is on a 100A feeder. And yes, it's wired properly, with separate neutral and ground.


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RE: Stumped on GFCI Circuit Breaker

I'm experiencing a similar problem. I have the situation where the GFCI circuit breaker located in the panel now trips immediately upon being reset to "on". This condition has arisen after the circuit was overloaded by the use of too many crock pots/coffee makers, tripped, and was repeatedly reset (i.e., worked as it should have). Now though, with nothing plugged in to draw current, the breaker won't hold the "on" position. I replaced the breaker and get the same failure. I inspected the two culprit overloaded outlets and couldn't see any obvious problems. I'm baffled and would welcome anyone's ideas.


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RE: Stumped on GFCI Circuit Breaker

In the case of the mysterious tripping GFCI breaker, I start by removing the circuit conductor connected to the breaker and cycling the breaker on-off. If the breaker holds, turn it off and reconnect the conductor. Go next to the outlet on that circuit nearest the breaker and inspect the conductors and device(s) found there. Disconnect the downstream feed from there and turn on the breaker. This procedure should eventually result in the breaker not tripping at one outlet and tripping at the next one downstream. The problem is at one of those boxes or between them.
With all due respect, if there is any part or aspect of this procedure that you do not understand, then you are not presently experienced enough to undertake solving this problem.

Almost all online definitions of "outlet" do not correspond with the definition of the NEC. An outlet can include the point a which a light fixture gets its power supply. See the link.

Here is a link that might be useful: Outlet definition-- scroll down


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RE: Stumped on GFCI Circuit Breaker

deleted this post

This post was edited by jimu57 on Tue, Feb 18, 14 at 7:49


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RE: Stumped on GFCI Circuit Breaker

Something else to consider. A GFCI receptacle can protect all receptacles downstream, but if you have 2 GFCI receptacles in the same circuit, you will get nuisance tripping. Make sure there is not more than 1 GFCI receptacle in a circuit. Also, make sure there is NOT a GFCI receptacle in the circuit that you have a GFCI breaker. Some thing will happen.


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RE: Stumped on GFCI Circuit Breaker

First off, something MAY happen. It's not certain. I have seen many DIY installations with GFIs fed off the load side of another GFI and they were FINE.

Second, this is from last November. I'd hope the problem was solved by now.


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RE: Stumped on GFCI Circuit Breaker

"if you have 2 GFCI receptacles in the same circuit, you will get nuisance tripping."
As Petey says-- not correct. Some plug-in devices/cords have their own built-in GFCI and they function just fine if plugged-in to a GFCI protected circuit.


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