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Changind single light switch to a double?

Hi, I've got a single light switch running a light in my garage, is it possible to change this to a double light switch to run an additional light in the garden, that is one switch doingthe garage light and one switch doing the garden light?
Many thanks

5 Answers from MyBuilder Electricians

Best Answer

It is quite acceptable to change the single switch to a twin switch to control the new outside light.

You will have to add some additional wiring, as it is most likely the existing garage light control switch will just have a permenant live supply and a return switch line back to the light fitting.

The new light in the garden will require a neutral supply, usually taken from one of the existing light fittings, or from a junction box, which will have to be cut into the existing loop circuit.

As an electrican I have wired many of these installations and my preference would be to remove the existing switch line and replacing it with a three core and earth cable.

I.E. One permenant live line, which can be bridged accross the new twin switch to control the new and existing light.
One return live line, to control the existing garage light
and one line to bring the neutral supply down, which can be connected to the neutral line of the new outside light within the back of the light switch box.

All of the above will depend on the type of existing installation,

I.E. most likely in the garage the wires will be clipped directly on the surface, therefore easily changed. Maybe they are in p.v.c. mini trunking, or round conduit ?

Either way quite a straight forward job, though as the new light will be outside, please assess the requirements for a residual current circuit breaker, which I would strongly recommend.

Why not post the job on this site and get some quotes ?


Adrian Hagger


Answered 4th Jul 2011

It is possible it may need the cable replacing from the garage light to the switch depending on whether the feed is going to the light or the switch. You can tell by the amount of cables going to the switch. I hope this helps

Regards Bradley


Answered 4th Jul 2011

Depends wether or not you have a nuetral in the light switch, If it has been originally wired with the feed through the switch then yes. If the feed goes to the light and just a switch wire to the switch(Perminent live, Switch live & earth) then you will have to install a nuetral to either the switch or outside light.
Hope this makes sense.

Jenga Electrical Solutions


Answered 4th Jul 2011


Yes it is possible. Depending on the wiring arrangement at the switch you might only need to run one cable from the switch to your new light ( that is if there is a neutral present at the garage switch ). If not you will need to run a cable from your switch to yoyur new light and also a neutral from your garage light to your new light. You will also need to register this work as it comes under Part P.

Hope this helps.

NJM Electrical


Answered 4th Jul 2011

Anything in the garden would come under part P, so you would have to inform the local authority first or employ a registered domestic electrician.


Answered 4th Jul 2011

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