# GFCI trips when light switch is turned off



## technicholas (Jan 1, 2012)

Hello,

I want to see if we could figure out why my GFCI trips when a light switch is turned off in the bathroom, if I turn it off fast sometime it's trips and sometimes if I turn it off slowly it trips.

I have no idea how the wiring works but once the GFCI trips the lights and fans still work.

One on the right is fluorescent bulbs, middle is fan, and the one to the left is shower light.

I attached a youtube video so we could figure it out.

http://youtube.com/watch?v=73n3nliYLW4&context=C3e0244dADOEgsToPDskJ1 F18iIOSlpyfJyc3UXDI-


Thanks!!
Nicholas

PS This is been like that when we moved in the house in 2003, this outlet is starting to get used more.


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## Julius793 (Dec 13, 2011)

Have you tried replacing the switch?


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## dougp23 (Sep 20, 2011)

Well that is one whacky video! Looks like once the right most switch tripped it, and once the middle switch tripped it. Maybe replace the GFCI outlet, they do wear out over the years. Not a pro here, just speculating.


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## frenchelectrican (Apr 12, 2006)

I can see the issue you may got the capaitve voltage when you hit the fan switch off and cause the GFCI to trip out so get a new GFCI recetpectale and most case it useally clear up.

Merci,
Marc


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## Stubbie (Jan 7, 2007)

You said the lights and fans still work after the gfci trips ... so there isn't any load side connections to the gfci protecting the fan or lights. Does the gfci trip after the fan is running for a while and then you turn the fan off ? I'd like to know how the wiring connects to the gfci receptacle. Also I don't think I saw a light switch trip the gfci only the fan switch.


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## theatretch85 (May 17, 2008)

My basement bathroom does this exact same thing. Turning off the fan causes the GFCI to trip, not every time but randomly. I've just shrugged it off and just deal with it. Bathroom is fed from its own 20 amp circuit and gfci has no downstream load. Fan and lights are wired past the gfci. Don't mean to steal the thread here but figure some additional input may help (and i'm curious as to why it happens).


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## Stubbie (Jan 7, 2007)

If there is no gfci load side protection to the lights and fan it just about has to be capacitive coupling from the fan motor windings. My guess would be that the gfci cable and the cable to the fan are stapled parallel to each other. The idea is that on start up of the fan the inrush current causes a voltage drop which in turn transmits a capacitive coupling to close by wires. This magnetic field pre loads the torridal coil in the gfci via the connected wiring. When you turn off the fan the coil un-loads and trips the gfci. 

Now I don't pretend to understand it but that in a nutshell is what I have read.

So the only simple cures ( if they work) would be to change to a modern gfci or change the fan out.


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