Adding new light on exsisting switch

[samgoffe]

I currently have 2 switches controlling 1 light in my house. Off of 1 of the switches, I want to swap it out for a 2 gang switch, then feed a cable out the wall to outside for an light.

This means replacing 1 of the switches with a 2 gang switch (it's currently 1).

A photo of what I currently have is attached. I'd like to know how to add the cable from outside to the 2nd gang.

I have tested that the single brown cable is constant live, regardless of the other switch. None of the other cables are live.


View media item 81673

 

[AndyPRK]

Well the new cable blue wire connect to blue in the back box. It's lucky u look like you have a neutral but test it before drilling holes.

Connect the new brown to the new switch L1

Connect com to the per meant live

 

[ban-all-sheds]

I have tested that the single brown cable is constant live,

Tested it with what?

If the answer is "neon screwdriver" then throw that away and get a multimeter.

Proper testing is going to be important - I can't see from the photo what's going on, but it looks like you have 2 x twin & earth and 1 x 3-core & earth, the brown from one T/E goes to COM, the other is connected to the brown of the 3C+E, and the black & grey from that go to L1 & L2.

The blues are probably neutral, but no guarantee.

How are all the various earth cores connected?

 

[samgoffe]

Andy's method has worked.

Yes it was a neon screw driver. All earth connected to the back box it's self, then 1 cable to the faceplate.