Double light switch wiring diagram

[ringolad]

I am replacing one of the lighting switches in my house and the new switch is marked up differently to the old one. The wiring consists of two red wires + one red loop, one black wire and earth. I attach drawing of the two switches.

The switch is for working two room lights separately. I bought a 2 gang 2 way switch.

I tried wiring up the switch and did get one light working but having tried various alternatives, could I have the wrong switch?

Untitled

• ringolad
• 20 Feb 2012
• 1

 

[ericmark]

I am sure I have already answered this? Anyway either don't use the L1's or don't use the L2's simple enough just put wires from Com to Com and 2 to L2.

 

[TicklyT]

A common mistake is expecting the top and bottom rows of terminals of switches like your old one to correspond to the two switch units, but they usually don't.

Have a close look at the back of the old switch and you will probably see a diagonal line moulded into the plastic, probably following the line of the link you have shown between the two 'Com' terminals. That line shows the division between the two halves of the old switch.

Your new switch has a different layout for the terminals, and the division between the two halves is more obvious.

Live feed to one 'Com' plus link to t'other 'Com'.

One switched live to each 'L1'.

If one or both switches work 'upside down', move the switched live from 'L1' to 'L2'.

 

[ban-all-sheds]

Plan B would be to put your multimeter (which you should have in exactly the same way that you should have screwdrivers etc) across pairs of terminal on the old switch, and by applying your knowledge of how 2-way switches work (which you must have, as doing electrics without a full understanding of how things work is completely unacceptable), identify which COM goes with which L1 & L2.