I installed a dimmer in my bedroom today and I just realised that the dimmer in my mom's room and in the corridor is not working anymore...

Followed standard procedure : Breaker off, changed the old switch for the dimmer and then turned the breaker on again and the dimmer is working fine.

I can't find any help online...

If it can help, it's a dimmer with a 3-way compatibility, but I didn't connect the wire for it.

I'm a beginner, I wondered if any of you could help, thank you. (Did I mixed up the Ground wire with the black one?)

enter image description here

  • 1
    Are the two dimmers on the same breaker, or different breakers? Can you post a photo of the inside of the box in your bedroom? Jun 15 '19 at 5:06
  • 1
    Were there any extra wires left over? Jun 15 '19 at 7:52
  • Did you record the positions of the wires on the original switch before starting? This may help you in sorting the issue.
    – Solar Mike
    Jun 15 '19 at 8:29
  • 1
    Hello, and welcome to Home Improvement. We'll need more info before we can help you, and please take our tour so you'll know how better to participate here. Jun 15 '19 at 13:26
  • I can't really test if they are on the same breaker now... You guys would want a picture from inside the dimmer?
    – monad
    Jun 15 '19 at 13:51

You really need a multi-meter or a non-contact voltage tester to find out which wires are hot, but if you want to you could try to do this without testing.

The white wires are "neutrals" (not grounds). Looks like you have bare grounds connected to the metal box with screws in the back. Leave those alone.

Do the B, R and W wires in the right cable go to the light in your room? If so, the B & W wires in the cable to the left are the feed to the hall and the other bedroom. The B is hot and the W is neutral. Somehow you disconnected the feed and did not reconnect it.

Probably the B and the R on the right were connected to the original switch. If so, one or the other of the B and R is always hot and the other is the switched hot which controls the light in your room.

The B in the left hand cable should be connected to the always hot from the right cable. The two W wires should be connected to each other (and to nothing else).

  • I screwed the ground from the dimmer to one of the screws and the two black ones to the black of the dimmer and everything was working well!
    – monad
    Jun 15 '19 at 23:02

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.