Hoping for some help I am fitting a new double light switch were one of the switches is a 2 way light.

The back of the light switch looks like this

  C          C

L1 L2      L1 L2

Now the problem I have is that I only have four wires and six connections. All of the wires are red but two of them have a extre grey sleeve ( I assumed these were the common wires).

I have tried wiring in the two commons then wiring switch one L1 connection and switch 2s L2 connection then bridging the L2 on switch one and L1 on switch two, I can get the two switches to work this way but only if the partner switch to the 2 way light is left on.

Where have I went wrong???


This is the schematic for wiring a pair of 2 way light switches: That means that two switches control one light and either switch can turn the light on or off.

enter image description here

Typically the L1/L2 wires are both red, or one is black and the other red. In no case should either of those be white.

  • 2
    In the US, sometimes L1 and L2 wires are black and white, but the white wire is marked with black tape or marker to show that it is hot. Also, in the diagram shown the neutral wire would be white. – bib Sep 11 '13 at 18:11
  • @bib: quite right. I forgot about the black wrapping or marking technique. It is NEC endorsed. – wallyk Sep 11 '13 at 18:33

Depending on your location, those may be 2-gang 2-way switches designed so that multiple switches can control each of two lights (e.g. switches at top & bottom of stairs and at each end of a hallway)

In which case they may have been wired up for 2-gang 1-way usage

Sleeved wires usually indicate switched live. I'd try to check this with a voltmeter or by inspection but you could try connecting the red wires to C and the corresponding sleeved wires to L1.

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