I’m trying to install a smart switch, from a 2 gang one way one dimmer (which worked fine) but it’s baffling me; it appears that two other rooms are affected as they both no longer work at all; I’ve installed the same switch in another room and it’s fine! In this room there’s an extra cable in this switch that’s grey in colour, whether the colour is of significance I don’t know, switching the cables around I can get power to the lights but can’t use the switch to operate them but I can’t understand why I can’t get power to the other rooms, or operate the switch oh I’m in the UK any help would be great. Cheers Dave (Sparky)

  • 2
    Hello, and welcome to Home Improvement. It's going to be hard for us to help without more info (e.g. a diagram showing the old and new wiring, photos of the insides of the boxes, etc). And, you should probably take our tour so you'll know the details of contributing here. – Daniel Griscom Nov 3 '20 at 16:10
  • I'm not sure what "a 2 gang one way one dimmer" means. Maybe it's a US/UK translation issue. I'm sure that pics will help, but some additional text to describe it may help, too. – FreeMan Nov 3 '20 at 16:29
  • It sounds like you did not connect the wires the same as they were. You will need to identify the incoming power from the mains and tie the other rooms to this then connect the new switch up to the light for that room. – Ed Beal Nov 5 '20 at 17:20

I would open up the two other switch boxes and take a look at what is going on. Then try to figure out if the switch powers the light or the line goes to the lights and then to the switch. Then check for voltage at various points. If you still can not solve the problem, put every thing back the way it was and check for voltage at various points and compare your test notes. I am not sure what you are saying but I suspect that the gray wire is the issue. It is possible a 3 way switch was installed and then removed. Also if you get a handle on when the wiring was done, someone may know about a practice that was done at the time.

  • I wojld start off putting it back the way it was but this is a common DIY failure not identifying the wires prior to taking things apart. At this point we don’t even know if the smart switch is compatible but it is probably the wiring. – Ed Beal Nov 5 '20 at 17:22

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.