I am replacing a 2 gang switch but foolishly did not note the wiring layout before changing it. One switch controls a porch light, the other an external light. One cable has a black and red wire the other cable has a yellow, red and black. New connections on the new switch are L1, L2 and live. Any help appreciated!!

Andy C, November 2006

Hi Ventris, thanks for your feedback. I gave you some wrong information, sorry. This double switch is simply a switch for the external light (Red and black wire only) and a switch for the internal porch light (Red, BLUE and definitely yellow. The red appears to be live). There are a couple of earths linked to the actual wall box and one from wally box to switch body (as it's metal). There are no other switches linked to it, i.e. no other switches can turn these two lights on. I've not tried your suggestion as yet but would you advice still apply?

Andy C, November 2006

Which light can be switched from two different locations?

I'm guessing that the red/black is for one light - the red probably permantly live & will go into the common/live terminal, the black - a switch wire which would go into L1.

The other cable, is it definately red/black/yellow or red/blue/yellow?( is the yellow actually green/yellow? "Earth")

If this is the case, then it is probably as above; alternatively,

If this is the two way switch, then the red is probably live(common) & blue/yellow will go into L1/L2.

if you check the other switch you will see which colour is in L1/L2 & should be fitted to correspond. If the two way turns on at one side but not at the other then it is likely the colours in L1/L2 are the wrong way round and need swopping over.

Hope this helps!!

Ventris the Volt., November 2006