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GFCI light switch trips once per night ????

9K views 11 replies 5 participants last post by  J. V. 
#1 ·
I just installed a GFCI outlet in a remodelled bath. From the GFCI, the line goes to a dimmer switch (for vanity lights) and from there to two switches (bath ceiling vent fan & light). The little light on the outlet is lit. All day long I can switch everything off and on endlessly and all works great. I can run power tools off the outlet. But at night, after everyone has gone to bed, if someone goes in and flips a light switch, the GFCI will trip off. Pressing the reset button restores power and you can again flip switches endlessly with no problem -- until the am hours the next night. This has happened every night for the last 5 nights.

Nothing else is on this circuit. It is a 20 amp breaker, 12-2 gauge wire. It runs directly from the breaker to the GFCI outlet. Does have a junction box along the run where I had planned to branch off of - but didn't.

I have no idea what could be doing this. Anyone else ?????????
 
#3 ·
"From the GFCI, the line goes to a dimmer switch (for vanity lights) and from there to two switches (bath ceiling vent fan & light). All day long I can switch everything off and on endlessly and all works great. I can run power tools off the outlet. But at night, after everyone has gone to bed, if someone goes in and flips a light switch, the GFCI will trip off. Pressing the reset button restores power and you can again flip switches endlessly with no problem -- until the am hours the next night. This has happened every night for the last 5 nights."

If the "light switch" that's flipped is on the dimmer, the dimmer switch may be generating interference which fools the GFI. The dimmer people might have a service bulletin out on this.

You might also check if the problem appears with the dimmer full on, or full off.
Also, before flipping the light switch, push test and reset and see if this stops the GFI from its expected shutoff after the switch is flipped.
 
#7 · (Edited)
Agree with Chris ....humidity problem. You have your lights wired to the load side of the gfci. Move the cable to the lights to the line side of the gfci. GFCI protection for the lights and fan is not required. You will still have the receptacle (gfci) protection. Checking the venting on your fan might help also if you keep the protection. I wouldn't....this is an example of wiring lights to your gfci load side you get left in the dark when your trying to take care of business.....:)..ie..my aim is good but I like to see what I'm shooting at....:thumbsup:
 
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