Im trying to change my light switch to a dimmer switch. However the wirings isnt what I had expected. There is an extra backstab wire aside from the hot and netural wire, there also no ground wire being used, and all the wires are the same color too.

dimmer switch

dimmer switch

dimmer switch

dimmer switch

What is that backstab wire for?

And is that exposed copper wire, inside the terminal, the grounding wire?

Why wasnt the white wire used?

Any advice or tips is greatly appreciated.

  • Your old switch doesn't have a ground wire. It doesn't need one - it picks up safety ground via the metal box and the mounting screws. May 29 '21 at 23:32
  • @Harper-ReinstateMonica oh that's how it works thanks. But my dimmer switch needs one right? Do I just unscrew the copper wire inside the metal box and wire nut it with the dimmer's green wire? May 29 '21 at 23:52
  • 1
    honestly what I would do there, is use a ground clip, which is a thing you'll need to go get. . All the cables landed on the ground screws in the back of the box, need to stay there. It does appear the screws are made to take 2 wires each; the one on the right is wrapped more than it needs to be. May 30 '21 at 0:40
  • @Harper-ReinstateMonica thank you! May 30 '21 at 0:49

The backstab wire is a continuation of the hot ,black, wire probably to or from an outlet or main panel, Just wire nut it to the black wire from the screw terminal right next to it and the black wire from your dimmer.

The exposed bare copper wire is the ground wire.

The white, neutral, wire normally isn't needed when wiring regular dimmers or regular switches. It goes straight from the switch box to the fixture without being switched. If you were wiring up a smart switch, you would more than likely need the neutral.

Turn off the power before doing any work.

  • Thanks Jack! So for the two bottom black wires (hot) I'll wire nut it with the back wire from my dimmer. And the top wire (the load wire) I will wire nut it with red wire from my dimmer. Then I have to unscrew the ground wire inside the wire terminal and wire nut it with the green wire from my dimmer, is that about right? And I turned off the power and used Multimeter to make sure. May 29 '21 at 23:12
  • @user1294510 They didn't do you any favors cutting those ground wires so short. Those three should be wire nutted together with an additional pigtail that loops through one of those screws in the box and extends to connect to your switch. You can't just separate one of the grounds and connect it to the switch. Only one of those are actually a ground and the other two become grounds by connecting them to the actual ground.
    – JACK
    May 30 '21 at 0:01
  • Thanks! So nut all the copper wire together and extend it with a pigtail, then the pigtail will loop through one of those screw (the other screw will be empty), and that will act as my ground wire? I think I got it now! thank you thank you May 30 '21 at 1:07

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.