New light on existing switch

[Gorners]

Hi all

I'm wanting to install an outside security light which will go on the outside wall of my garage. On the inside of the same wall there is a single switch that operates the internal garage light.

I was hoping to convert to the single to a double switch, with one switch controlling each light. I understand that I will need a neutral for the outside light which is not often found at the switch and I might need to pull a neutral from the light itself.

I've had a quick look at the switch after work and was expecting to see just live and switch live (and earth), but there are actually 2 red (one connected to unmarked terminal and other to L2), and a black wire connected to L3, plus earth.

Long story short, am I in luck and one is a neutral, or is this setup just an extra live?

 

[PrenticeBoyofDerry]

Is this a two way light, is there another functional switch that operates the light?
I guess two way light, with loop-in live and no neutral

 

[Gorners]

Yes of course I'd completely forgot about that - the other switch is in the kitchen.

Damn - can't seem to find any how-to's of pulling a neutral from the light itself. The existing cable is in plastic casing up to the ceiling and then goes about 3 metre above the ceiling into the light. Is it a case of finding the right cable at the light, atttachkng the new cable (tape?h and pulling it through from the switch?

 

[PrenticeBoyofDerry]

Is the garage detached or attached?

You also need a switch line and a CPC/earth.

 

[Gorners]

Attached.

 

[PrenticeBoyofDerry]

Well to make it work at the switch, you would need to pull a neutral loop in at the switch that is two cores for neutral, one to supply a neutral at the switch and one to go to light.
Can you not loop the neutral for the garage light to the outside light.
You will still need to pull a switch line and CPC to the switch though!
I would also establish that you have a perm live at switch and a fault path to earth first!

 

[Gorners]

Thanks a lot for the responses. Yes I could pull the neutral direct to the outside light which would make it a bit easier. No issues with the CPC.

How do you pull a switch line through if I'm not replacing the existing cable? Don't know why I can grasp the electrical concepts but getting a wire through I can only see floorboards up as an approach !!

 

[PrenticeBoyofDerry]

You need to use the permitted safe zones,
//www.diynot.com/wiki/Electrics:Installation-Techniques
look at wall and floor routes!
Also newly buried cable will very likely require RCD protection if not present?
How you get it to the switch, well that would depend on a number of things, hard to say without seeing it in real life!
But suspect if there is no void for the cable to go in to the switch, then it is a hammer chisel jobbie!