What would cause a GFCI outlet to trip?

[L5wolvesf]

The area all around the outlet (wall and floor) is dry, and nothing was operating except the ON indicator for a phone which is plugged into the same outlet. No storms in the area and all the other garage outlets are working.

The outlet was installed within the last few months in an area of the garage that has a washing machine. The outlet has operated fine since I put it in as a safety upgrade. When I installed it my plug in circuit tester showed 2 green lights (“Correct”).

That outlet is on the same circuit breaker which also has a couple other non-GFCI outlets. The only thing those outlets have on them are a pair of switch operated 2 bulb florescent lights. The outlet switch does not operate the GFCI outlet. Everything (washer & lights at the same time) has worked good so far, like it has for the last 5 years.

So, yesterday when I went to turn on the lights there was a slightly audible pop (or click) and no lights came on. Today after checking things out I found that the GFCI outlet had done its thing, but the circuit breaker had not tripped, and there was no juice to the switch. I reset the GFCI and plugged in my circuit tester – it showed 2 green lights (“Correct”). All is back as it was before.

Any idea what may be going on? What else would cause a GFCI outlet to trip?

Thank you,
L

 

[Roots]

Some lighting ballasts, particularly cheap ones, play havoc with GFCI's. Generally due to poor construction methods of the ballast.

Those three light testers are not entirely accurate as well, even though a lot of people use them. They can be 'tricked' both intentionally and by accident.

 

[spongerich]

I F$#$&ing hate GFCI's sometimes (except for when they save your ***).

 

[jbberns]

I wouldn't worry about it unless it keeps happening.

 

[Frank The Plumber]

Lightning strike in the vacinity of your wiring.

 

[Jarhead0408]

Heavy rain does it at my house for some reason. but only the gfci that connects to an outside private lightpole.

 

[Kevin C]

As best as I can tell, it might be something to do with the odd harmonics from EMI filters on the ballasts. While I haven't found an article analyzing the problem direcly using lights, I did find an analysis of the GFIC and the EMI filters used on a variable speed drive.

The root cause should be the same...

http://www.jonathankimball.com/pdf/gfci_ecce.pdf

Still looking...

Basically the fluorescent lights can bring the GFIC close to the tripping threshold. A bank of 6, 4' double bulb T8 lights will trip my GFIC pretty regularly.

 

[matt151617]

It could be general dampness too. I had mine trip once on a humid day. There was probably a little moisture accumulation on the plug.

 

[dipper]

like all consumer grade products manufactured these days (and most likely made in china) the outlet itself could be defective. replace it or swap it with one that is in known good working order.

 

[Jason641]

The switch and lights do not need to be wired through the GFCI, the light fixtures are probably causing your issue. To fix this you can install a separate GFCI at each outlet location and keep all the wires on the "LINE" side of the receptacle. Anything hooked to the "LOAD" side will be protected by the GFCI and potentially make it trip. If you know exactly which outlet location has the feed going to the switch/lights you could install the GFCI there and keep the lights and the line in from the panel on the LINE side of the receptacle and the additional receptacles can be hooked to the LOAD side.

 

[I void warranties]

agree above^^^^^ also i agree with the ballast theory... i had to change 6 ballasts before i found the culprit. even a amp meter will just barely read the max amps on a ballast at start up.

 

[jbberns]

like all consumer grade products manufactured these days (and most likely made in china) the outlet itself could be defective. replace it or swap it with one that is in known good working order.

After tripping one time?

 

[L5wolvesf]

Lightning strike in the vacinity of your wiring.

It could be general dampness too. I had mine trip once on a humid day. There was probably a little moisture accumulation on the plug.

No rain and few clouds in weeks before this happened. Have had rain since GFCI was installed with no problems I’m in AZ, it’s a dry heat

like all consumer grade products manufactured these days (and most likely made in china) the outlet itself could be defective.

The outlet was new, and only a few months since installed.

Basically the fluorescent lights can bring the GFIC close to the tripping threshold. A bank of 6, 4' double bulb T8 lights will trip my GFIC pretty regularly.

I just have a pair of 4 ft, 2 bulb T12s on this circuit.

Some lighting ballasts, particularly cheap ones, play havoc with GFCI's. Generally due to poor construction methods of the ballast.

Anything I can do to address this other than replace the fixtures? They will be replaced as they go bad.

Thank you,
L

 

[L5wolvesf]

The switch and lights do not need to be wired through the GFCI, the light fixtures are probably causing your issue. To fix this you can install a separate GFCI at each outlet location and keep all the wires on the "LINE" side of the receptacle. Anything hooked to the "LOAD" side will be protected by the GFCI and potentially make it trip. If you know exactly which outlet location has the feed going to the switch/lights you could install the GFCI there and keep the lights and the line in from the panel on the LINE side of the receptacle and the additional receptacles can be hooked to the LOAD side.

Not sure I fully understand what you are saying. I only “need” (for safety around a potentially wet area) a GFCI outlet for the washing machine. The other outlets (ceiling mounted) in the circuit are used for the florescent fixtures.

I guess the switch and lights are wired through the GFCI since the whole circuit was dead when the GFCI popped. I didn’t think that when the problem first happened. The outlets the lights are plugged into are activated by the switch. The GFCI outlet is always active.

Thank you,
L

 

[spongerich]

I’m in AZ, it’s a dry heat

You know what else is a dry heat?

Fire

(Which is only slightly cooler than Phoenix in August)

 

[jeff000]

After tripping one time?

Possibly even before the first trip.

The switch and lights do not need to be wired through the GFCI, the light fixtures are probably causing your issue. To fix this you can install a separate GFCI at each outlet location and keep all the wires on the "LINE" side of the receptacle. Anything hooked to the "LOAD" side will be protected by the GFCI and potentially make it trip. If you know exactly which outlet location has the feed going to the switch/lights you could install the GFCI there and keep the lights and the line in from the panel on the LINE side of the receptacle and the additional receptacles can be hooked to the LOAD side.

This.

Not sure I fully understand what you are saying. I only “need” (for safety around a potentially wet area) a GFCI outlet for the washing machine. The other outlets (ceiling mounted) in the circuit are used for the florescent fixtures.

I guess the switch and lights are wired through the GFCI since the whole circuit was dead when the GFCI popped. I didn’t think that when the problem first happened. The outlets the lights are plugged into are activated by the switch. The GFCI outlet is always active.

Thank you,
L

You don't actually need a GFCI for a washing machine, not in Canada anyways. And my copy of the NEC may be outdated.