Bathroom GFCI tripping

[Dragster Racer]

I'm scratching my head a little with this. The bathroom gfci breaker (in the main panel in basement) trips after the bathroom gets steamed up. And only when the fan or light (in the same fixture) are turned on. I looked at the wall switches, and nothing looks ary there. The wiring for the fixture is all above the entire fan assembly, and I can take that down, but with the way those sheet metal fixtures are made, I'm afraid it will never take it's form back. The fan and the light plug in inside the fixture and that is visable. All the rest of the lighting is above the fan.....and I would think less vulnerable to moisture since it is above the ventalation. Not sure how to test to find the problem here. Any help?

 

[Aceman]

Is the fan sized properly? I usually shoot for 6 air changes an hour. There are some online calculators that'll help you size bath fans.

Is the ductwork in good shape? Free and clear of obstructions, roof vent isn't plugged with leaves, etc?
Do you have a sufficient gap under your door to provide enough intake for the fan when the door is shut?

How old is the fan/light combo?

Does the GFCI breaker only feed this bathroom? Or could it be feeding outside receptacles too?

 

[Dragster Racer]

Good questions. It isn't draw on the fan, since the light only can trip it when it is steamy. Now, is it big enough for the bathroom? I'm not sure, but it was the largest I could buy at Lowes I believe. So I would guess we are ok there. It only gets steamy with back to back showers, and even then, it isn't all that bad. It's going on two years old...as is the house. I can see the vent, and the flappers work ok outside. The only things on the circuit are the fan/light, the vanity outlets and the vanity lights...and the shower light. The fan/light is the only thing that will trip it when it trips. If it trips, we have to use the water clothest fan to clear the moisture since it will keep tripping until the moisture clears.

 

[ishiboo]

Chances are at some point in the fan/light assembly, moisture is collecting and causing some leakage from hot to ground. Unless it's brand new, an expensive fan and/or you're attached to it, I'd replace the fan.

 

[Mr_fixit]

I'm scratching my head a little with this. The bathroom gfci breaker (in the main panel in basement) trips after the bathroom gets steamed up. And only when the fan or light (in the same fixture) are turned on. I looked at the wall switches, and nothing looks ary there. The wiring for the fixture is all above the entire fan assembly, and I can take that down, but with the way those sheet metal fixtures are made, I'm afraid it will never take it's form back. The fan and the light plug in inside the fixture and that is visable. All the rest of the lighting is above the fan.....and I would think less vulnerable to moisture since it is above the ventalation. Not sure how to test to find the problem here. Any help?

Yes, mine too. Turn the fan on. That solved my problem.

 

[Dragster Racer]

The fan is always running when it trips. It's kind of a fancy light fixture, so I hate to trash it. But if it keep s it up, I will probably have to. I could chase this forever. LOL>.

 

[ishiboo]

The fan is always running when it trips. It's kind of a fancy light fixture, so I hate to trash it. But if it keep s it up, I will probably have to. I could chase this forever. LOL>.

So, replace the breaker. If it's not the breaker, put your old one back (so you are returning the almost brand new one) and return it to the store

 

[Tom Hintz]

We had a GFCI circuit that tripped without apparent reason. Then quite by accident I discovered that one of the outdoor outlet sets was tapped into the GFCI circuit! That socket set was getting old and apparently susceptible to moisture when it rained. for a day or so after a rain, using that circuit in the bathroom wold trip the GFCI circuit. A new, better grade waterproof socket set cured our problem except when somebody is plugged into the outdoor socket and somebody else tried to use a hair drier or something. That can still trip the GFCI breaker occasionally.

 

[hh76]

I'd guess that the extra moisture in the air is allowing some current to flow from a scratched or nicked wire. Typically occur where all the wires are stuffed in a box and rubbing up against each other. My guess is that if you pulled out the fixture and re-arranged the wiring, it would stop. These types of faults are notoriously difficult to find because you don't always find a smoking gun, and can go away when conditions change.

Insulation tester or megger could narrow things down, but they are pretty expensive and can be tricky to use.

 

[May Pop]

What kind of bulb is in the fixture? If its a flourescent [compact] it may not be making enough heat to dry the fixture. Also flourescents will cause GFCIs to nouscince trip.

 

[Dragster Racer]

It is a cfl, but we really don't use it all that much when we run the fan. Two switches. And we have other lights in the bathroom and shower. I kind of wondered about the manufacturer intending on the light heat drying things out a bit. Funny, we haven't had it do it in over a week now. Maybe I can talk the wife into a long hot shower....for testing purposes. Probably not. She makes few sacrafices in the name of science.

 

[Kevin54]

Just wondering if your vent pipe to the outside is sloping towards the outside or a possibility that it is letting condensation run back to the vent itself allowing the condensation to drip to where it pops the breaker? Just a thought.

 

[Dragster Racer]

Anything is possible. But the air should be sealed from the electric at that point. Should being the word.
I think probably I will have to bite the bullet and take it down completely and move the wiring around and examine it. It will either make it better or worse. LOL.

 

[fefarms]

Anything is possible. But the air should be sealed from the electric at that point. Should being the word.
I think probably I will have to bite the bullet and take it down completely and move the wiring around and examine it. It will either make it better or worse. LOL.

Fluorescent tubes exhibit some capacitive coupling to nearby grounds. This would get worse with wet air. It may be enough to trip a GFCI. Try an incandescent bulb or a compact fluorescent bulb which has an outer glass globe around the spiral tube.

It is also possible the CF bulb has a hot to ground leak.

 

[Dragster Racer]

But would this be a problem if we don't actually use the light when it is usually tripping?

 

[CADPoint]

With the cavity in the wall with the switch box is it creates a difference of pressure and the humidity is drawn across or into the box.

The GFCI should be tamperproof and a water resistant device if your going to replace it, I would

 

[Dragster Racer]

It's on a gfci breaker in the breaker box.

 

[osu69]

Check for dust accumulation around electrical connections in the fan unit. After a few years, these units pack with dust and lint; when exposed to humidity the dust becomes soggy and conductive.

 

[kenfath]

Keep in mind GFCI breakers go bad. For no apparent reason our GFCI breaker would trip. At first it was monthly, then weekly, then almost daily. Three bathroom and one sheltered outside outlet were all that was on the circuit. I had disconnected the wire from the GFCI and was testing the circuit (which was OK) when the phone rang. ~20 minutes later came back to find the GFCI breaker, that I'd purposely left on, had tripped. Replaced breaker and 'another' problem solved!

 

[Dragster Racer]

I think I have one of those out in the shop for the outside outlets. Starting to tick me off.
I can't believe it, but this darn think in the bathroom hasn't tripped for weeks now. I probably just jinxed it, but maybe it was unplugging and replugging the light and fan. Touchy gfci. I get aggrivated with them, but I don't much like getting shocked either.