[captainron19]

Strange scenario.

Spare bathroom I have a 3 switches on wall (all single pole)
1 is for single bulb over sink, 1 is for main light fixture and 1 is for exhaust fan.

This week I replaced the main light fixture. I originally had a "no frills" light that had 2 small fluorescent tubes in it. I replaced it with a flush mount LED light fixture from Home Depot. Unit is actually a sealed unit

I did nothing with switches (just replaced fixture)

After everything was installed light worked fine but I noticed that if light was off and I turned on exhaust fan then turned fan off... the new light fixture blinked (maybe for a millisecond) It doesnt happen every time I turn the fan on then off (maybe every third or fourth time).

I also turned the single vanity light on over the sink and when I turned that off it happened again (The main ceiling LED light flashed for a sec).

I did nothing with the switches on the wall as I just replaced the main light.

Could it be that the LED fixture pulls so little of a draw that it is somehow allowing some current to go through switch even though it is turned off?

 

[NickTheGreat]

Just regular switches? I've heard of LED's doing weird things like that on dimmers.

 

[captainron19]

yes .... regular switches ... no dimmers

 

[GottaFixIt]

LED's have built in circuitry that is really sensitive. It may just be seeing the slight momentary drop in voltage and reacting.

It would probably make sense to check the circuit for any loose connections or voltage drop, though.

 

[Oso954]

IMO, you are getting a capacitive discharge. The conductors for the light and fan are close to each other, if not in the same cable. The current for the fan is producing a voltage on the light conductor. This charge is being stored in the LED circuitry and/or on the conductor. Once the charge reaches a trigger level, shuting off the fan and the collapse of the magnetic field triggers the capacitive discharge on the LED circuit.

Your previous light was immune as it either bleed off the charge or the discharge was not large enough to cause the flash.

 

[captainron19]

Thanks Oso954 - I was talking to an electrician friend of mine and he said that makes complete sense

 

[Mshow1323]

That's really strange, this identical question was asked over on Electriciantalk on Thursday the 25th . What happened to the electrician on the job? Do you relieve him of his duties? Did he walk away? Just curious really.
http://www.electriciantalk.com/f8/problems-led-trims-146041/

 

[captainron19]

Did I relieve what electrician? I was the one who put the light in