GFCI keeps popping

[BobT]

Quote:

How would this not meet code?

I had the impression this circuit was supplying more than the bathroom.

[CAMAN]

Is the fan hooked up to a separate switch or does it come on with the lights? CFL or incandescent lighting?

Three seperate switches, one for each item. The switch for the sink lights is a standard switch, the switches for the fan and shower light is the stacked type switch (two switches in one box)

The light above the shower is an incandescent in a sealed can fixture. The lights above the sink are incandscent also.

[JohnMickish]

To help troubleshoot this further, take the fan cover off and unplug the fan from the housing. Use the bathroom as usuall for a week or so and see if the GFCI trips or not. It it stops tripping it is the fan causing the problem.

Now, the problem is changing the fan probably wont fix it, maybe it will but maybe it won't. The fan has a motor, and the way motors start (current induction) is what will trip a GFCI.

If that dosen't issolate the problem (I am betting it will) tape off one of the other switches for awhile to see if you can narrow it down to one item, then work from there.

[Surface Tension]

I think I'd take the fan out of the equation.

[CAMAN]

So you guys are saying the fan (or something) could trip the GFCI even though there is zero power going to it...because the switch is off, and always has been, it only runs when needed and has never tripped while running.

[Surface Tension]

It trips by itself and not when in use.

You replaced the GFCI.

I'd trip it then go around and check what else isn't working, inside and out.

[JohnMickish]

Let's back up and get all of the info out. Electrical problems are very hard to diagnose, and it makes it harder the info comes out in pieces.

Does it trip by itself or when a switch or switches are flipped on?

[JohnMickish]

My moms house (18 years old and basement finished 8 years ago) has a GFCI outlet in the basement bathroom that keeps popping randomly for no obvious reason. It started doing it over the summer. It only does it when the lights and fan is off and there is nothing else connected to the circuit that I can find. I replaced both the circuit breaker(was too big) and GFCI outlet with brand new ones. It kept happening so I checked the fixtures and found the lights above the sink weren't grounding right, so I replaced that and it still happens. I have checked and replaced all the outlets and switches to make sure nothing is touching or bare and its all good. It still happens and I am stumped.

Anybody have any ideas or ways to diagnose this better? I'm hoping there isn't a bare or chewed up wire in the wall somewhere.

Thanks!

Ok, after re-reading this, if it trips when nothing is in use (all switches are off) you either have a bad GFCI or there is another load on the circuit somewhere, which would be a code violation.

If it is not the GFCI the only other thing it can be is the wire running from the load side of the GFCI to the switches could be bad.

If there is nothing else connected in the circuit somewhere and there isn't anyting plugged in to the GFCI and the switches are off the only place it can be is the feed to the switches or another bad GFCI. There should be zero amps draw at this time.

By chance, do any of these switches have a pilot light or dimmer built in to them?

[BobT]

Not trying to second guess here but are you sure it is tripping when nobody is around and all power is off? GFCIs can trip pretty quick and I'm with mnfishinguy that it might be tripping as you apply power (turn on a switch). If there is a ground fault, it can react fast enough that you wouldn't see a light even flicker. What I read one time was that they are suppose to be able to react so fast that you wouldn't feel a shock if you became the grounding path. I wouldn't want to test this theory but...

[Dave]

I always thought GFI's were suppose to be for outlets only and not fans or lights.

[BobT]

I may get corrected by the electicians in this thread but if memory serves me correctly, the bathroom circuit may supply all outlets in the bathroom. The receptacle outlets must be GFCI protected (within x distance from water basins?) but there is no restriction that I am aware of that would prevent using the GFCI to protect the rest of the circuit as well.

[JohnMickish]

Bob is right. Besides protecting receptacles within X distance from a water basin, lights and fans with X distance of the tub have to be protected too, and it dosen't matter if you do it with a GFCI receptacle or GFCI breaker.

[dillrodd]

You're citing current codes. Don't recall what was allowed in 1992 but maybe this was? Based on the description of what outlets are going dead when this GFCI is tripping, the circuit does not meat today's code as it is. Regardless, he's left working with what it is and it doesn't help him to read a lot of arguing about what the code allows today vs. what it did 20 years ago or whether it was a lazy electrician, efficient electrician, homeowner with a low budget, or whatever because non of that matters now. [/quote

I find it interesting that Bob T felt the need to complain about getting of topic yet when i come back this has turned to a code dicussion. As early as tht 1990 code all receptacle outlets installed in dwelling unit bathrooms (125 volt 15 and 20 amp) require GFCI protection regardless of their location to the basin. Back then that circuit could go any where in the dwelling inside or out. The current code is that the bathroom shall be provided with at least one 20 amp branch circuit to supply receptacle outlets and shall contain no other outlets. The exception is NEC 210 11 ©3 Exception which says where the circuit supplies a single bathroom other equipment located in th same bathroom shall be permitted to be supplied.

[BobT]

I was concerned that this thread was turning into a bashing of electrical contractor ethics and not addressing the issue of the original post, which was why his GFCI keeps tripping. Whether the installation was up to code or not is not the issue, that's all.

I responded to Dave's statement because I thought he was eluding to the possibility that the problem might be the motor load on the GFCI. There are some that suspect or believe that single-phase inductive loads, like motors, can trip GFCIs but unless there is a ground fault in the motor, that current should be matched on both the hot and return legs.

Motor loads do not present any problems that I am aware of. My refrigerator is plugged into one of my small appliance circuits. We've used the small appliance outlets to operate our vacuum cleaner without issue. Microwave ovens, electric mixers, etc. are inductive loads, which is what small appliance circuits are suppose to supply. My bathroom GFCI serves the lights and ceiling fan as well and we haven't had any problems with that either.

With all this said having the ceiling fan on the circuit, whether in violation of today's code or the code in 1992, shouldn't be a problem to the GFCI.

Is it possible that an arc fault could trip a GFCI? I know they are not designed to detect arc fault but maybe...?

[dillrodd]

Bob T is right on when he says that motor loads are as a rule not any issue at all when on GFCI. All temporarary power on job sites are required to have GFCI and very rarely does anynone complain about nusiance tripping.Although GFCI is designed to trip on differential between the ungrounded conductor and the grounded conductor (neutral) the GFCI will also trip if there is contact between the Ungrounded conductor and the grounding conductor. The fact that this GFCI is tripping with the switches off would cause me to look at the latter. an example would be the lamp socket he refered to earlier

[BobT]

Quote:

the GFCI will also trip if there is contact between the Ungrounded conductor and the grounding conductor.

That's exactly right. If contact exists between the ungrounded and the grounding conductor then you have a ground fault and current will flow on the ungrounded (hot) conductor and not on the grounded (neutral) conductor. A measurable difference in current between the grounded and ungrounded conductor will be detected and the GFCI will open the circuit by design.

I think if this circuit is tripping when the homeowner is not using it, it is quite obvious that there is some current flow between the ungrounded conductor and the grounding conductor. Is it possible that some mice have been busy? There could be some damage or degradation to the insulation of the ungrounded (black) wire inside one of the fixtures or receptacles allowing incidental contact to ground. Also, consider taping the wirenuts in the outlets to make sure the grounding wire (bare) can't somehow make contact with the ungrounded conductor inside the outlet. I've seen that happen before.

[dillrodd]

Sorry, what I meant to say was between the grounded conductor and the grounding conductor. I still think hooking to an arc fault breaker may make this easier to trouble shoot

[JohnMickish]

A motor load is not supposed to trip a GFCI but if you have spent any time with GFCIs you will have on more than one occasion found where they do. I once had a garage GFCI that would trip when a block heater was plugged into it. Now a resistive load isn't supposed to trip it but here it did.

If all of the info is out there, and if everything is in good condition and all there is on this cirucuit is a GFCI, two light fixtures and a bath fan, I'm going to put my money on the fan. Now if the basement had been flooded at one time or another or has been subject to extreamly high moisture levels I reserve the right to change my mind.

[CAMAN]

Ok, just to explain how I know it trips when nothing else gets switched on or off. I was house sitting for a couple weeks and staying in the basement bedroom, I would go to bed and the green LED light on the GFCI saying the outlet is powered would be lit and I could see the light from my bed. When I woke up in the morning after nothing else in the house is switched on or off it would be off. And yes, I checked the sump pump, furnace, refridgerator and whatever else I could think of that would be automatic and they are all on different circuits.

I still don't understand how a fan that has zero power running to it because the switch is off can trip a breaker.

But anyway, I didn't really mean for this thread to turn into a codes or electrician debate, just trying to get some other ideas to try. I will probably run a temporary line from the GFCI outlet to the switches for a few weeks to take that wire out of the equation, and go from there.

Thanks for all the input. I'll let you know what I find.

[BobT]

No debate. Sometimes it can help troubleshoot a problem when one makes certain to understand the function of the circuit as best he can. Each time we do this we learn a little from others' experiences. I don't work hands-on with GFCIs but I use them in my designs and read a lot of manuals. If I remember correctly, mnfishinguy is a contract electrician and his hands-on experience is invaluable. Not sure about dillrod but from reading his posts, I'd suspect he too works in the electrical field. My suggestion is to listen to them more than me.

[JohnMickish]

OK, since it does it by itself IMO the only thing it can be would be a faulty GFCI. I know you replaced it once, but if nothing is on then it has to be the problem. With the switches off it shouldn't matter what is downstream from them.

I hate to send you out to buy parts but.....it's all it can be, or else you have ghost that do things in the bathroom you don't know about.

If you do go get another one purchase a comercial grade 20 amp GFCI, not the $8 big box made in China special.

[sparkyaber]

Little late here, but pull the load wires off the GFI (if you can get by without lights for awhile). That will tell you if it is the GFI or something on the load side. I am leaning toward a second bad GFI, I have seen stranger things.

[BobT]

That's a good idea. Too simple to have thought of it earlier.