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hi all, went to replace a dimmer with a conventional light switch and found this wiring, it's different to what I've seen before (I'm a bit of a novice and can do basic wiring). Anyone able to point me in the right direction as to what wiring i have here? Thanks in advance.

  • You may want to add what country you are in. Your conductor colors aren't the standard for North America.
    – ArchonOSX
    Jun 3, 2016 at 9:08
  • Oh ok sorry. Am new to the site and didn't realise. I'm in the UK.
    – Ben
    Jun 3, 2016 at 9:15
  • Do you have a picture of how it was originally connected? Also, it looks like the yellow wire goes back to the earthing point - is this correct? Jun 3, 2016 at 9:15
  • I took it off expecting to be able to replace trouble free so never took a pic. And yes the yellow come from earthing point.
    – Ben
    Jun 3, 2016 at 9:17
  • OK. Should be just a case of get rid of the yellow wire (it was probably illegal in the first place, and we don't need it), and connect the dimmer to the two red/red-sleeved wires - either polarity. Jun 3, 2016 at 9:29

1 Answer 1


Anyone able to point me in the right direction as to what wiring i have here?

  • Red - permanent-live feed from lighting circuit (240V AC)
  • Black with red sleeve - switched-live from switch (to luminaire).
  • Green - earth to metal backbox.
  • Yellow - earth from metal backbox to metal body of dimmer - no longer needed, remove.

A typical UK light switch will have three wiring positions, secured by screws, labelled L1, L2 and L3. L1 will be at one end of the switch, L2 and L3 will be close to each other at the other end.

Connect the red wire to L1 and the red-sleeved black wire to L2.

If you remove the yellow wire (which you should to avoid inadvertent shorts when refitting the frontplate) - I would make sure green is still securely connected to the backbox - this provides an earth to the exposed machine-screws that hold the front-plate.

  • Many thanks for the advice. Much appreciated.
    – Ben
    Jun 3, 2016 at 10:19
  • I have added a pic above, would this wiring fit this switch or do i have to replace with a dimmer switch?
    – Ben
    Jun 3, 2016 at 10:24
  • Yes you can use that switch, connect red live wire to the position labelled "COM", connect red-sleeved black to "1WAY". Jun 3, 2016 at 10:26
  • The best way to express thanks is by up-voting an answer, or by accepting it, using the tick mark, if it is useful. Jun 3, 2016 at 11:12

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