Quick question. In my bathroom I have a 2 switch electrical box. One switch is a dimmer and the other controls the fan. I need to replace the dimmer switch with another dimmer switch. I connected the black wires and everything works fine but there is a ground wire on the new dimmer switch (no ground wire from the old dimmer) and I don't know where to hook the new ground wire up to? Do I hook it up to the ground screw part on the fan switch (that would have the fan ground wire and the dimmer ground wire). Do I not need the ground wire for the new dimmer? Thanks!

  • 1
    If you want further and more specific guidance, take a picture or draw a diagram that shows the current wiring.
    – gregmac
    Commented Aug 7, 2015 at 18:44

1 Answer 1


Some dimmers use the ground to trickle a small amount of current for normal operation. If yours is working without it connected, I would say it doesn't fall into this category (although you could provide the model name/number to be certain).

Most likely the ground connection is there simply because all residential switches, receptacles, etc. require a ground these days.

It sounds like a ground wire is available in your switch box, but it is going to your fan's switch. No, you cannot double-tap the ground screw on your other switch. You need to use some form of wire connector to make what is called a pigtail to connect the ground from each switch to your ground wire in your switch box.

Illustration of the pigtailing concept enter image description here

  • 2
    +1 But note that the illustration is not for a switch but an outlet. It is meant to demonstrate the use of pigtails in general, not the wiring described in this particular question.
    – bib
    Commented Aug 7, 2015 at 13:30
  • @bib, Yes, thank you, I should have made that more clear.
    – mjohns
    Commented Aug 7, 2015 at 13:31
  • Thanks so much. It's a Cooper dimmer, model #TI06I-W-K-L
    – Kelly
    Commented Aug 7, 2015 at 14:10
  • @Kelly, I see no notes about the ground being used for operation, but you should still connect it from a safety and code-compliance standpoint.
    – mjohns
    Commented Aug 7, 2015 at 14:21
  • I'm confused about the pigtailing. I'm not sure how to take the one ground wire that is connected to the fan switch and use that to make another wire available to use on the dimmer side. Is there a video I can watch? I think I'm making it more complicated in my mind.
    – Kelly
    Commented Aug 7, 2015 at 17:42

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