I have a 3-gang box, There are 3 14/2 NM cables coming inside box. One is the power supply, the other 2 are for the light switch and bathroom fan. I want to install a timer switch for the bathroom fan and also want GFCI protection for the fan. Is my wiring diagram correct?

Also, the timer switch has 4 stranded wire coming out of it, Should I directly connect black wire to GFCI load side or should I use wire connector to join them ?

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Timer | GFCI

1 Answer 1


This looks correct to me. Key pieces:

  • All grounds together.
  • Light is switched and powered not on GFCI. This is normal and generally preferred, with the exception if the light is directly over a tub/shower.
  • GFCI blank face. My preference generally would be to make use of it as a receptacle for almost no extra cost. However, since bathroom receptacle circuits are supposed to be 20A, while existing 15A receptacles would be grandfathered I think new receptacles would not be. (Changing to 20A would require 12 AWG wire.)
  • Timer after the GFCI. Note that timer actually probably does not need to be GFCI-protected, unless the fan is over a wet area (tub/shower). But if it is going to be on a GFCI, it should be after (as you have it), not before.

I would recommend using wire nuts and a pigtail rather than directly connecting the timer to the GFCI. That will make any repairs/replacement easier.

  • 1
    Thank you, it worked. Commented May 22, 2021 at 21:54

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