How to change a 2 gang switch into a 3

[Hightowermark]

Hi i'm looking at adding another light. We have atm a 2 gang switch 1 is for the main light the other for side lights. So i want to add another light which will run off its own switch.

I have enclosed pictures as they speak a thousand words.

 

[ericmark]

It would be normal to take a cable to the switch from the new light and has nothing to do with old wiring.

However I note two wires into one switch and wonder it all you want is to split again?

If so then link all Com together and also use wire already going to link I would put tape on that wire to identify as line feed.

Then one wire to each 1way hole.

If however it is new fitting then you need to get an extra cable down the wall.