Adding outside lights

[Conan325]

My kitchen light is fitted with 1 gang - two way switches. I would like to change the one nearest the outside door to a 2 gang - two way switch inorder to add an outside light. The present switch is wired as follows:-

red - common, yellow - l2, blue - l1.

How do I add the new cable to the new 2-gang switch?

 

[ericmark]

Forget about the cables already at the switch.
Take a supply from the ceiling rose down to the switch I tend to use grid switches as you can get these double pole so no junction blocks required in backing box. And the from switch to light.
The existing wires will not have a neutral and may not even have permanent live depending on how wired so are completely useless to you.
Eric

 

[breezer]

as ericmark says, you cant do as you suggest (from the information you have given)

see the wiki and sticky for infor how its done, oh, and as its a kithchen you need also need to comply with part P

View media item 1257

 

[ban-all-sheds]

You need to comply with Part P wherever the work is. Part P applies to all work on LV & ELV installations that are in or attached to dwellings etc etc etc...

 

[ericmark]

OK you will need to notify LABC or use a registered electrician under Part P for work in a kitchen.
Yes I know all work has to comply with Part P but not all work needs notifying and when people refer to Part P we normally mean notifiable rather than has to comply.
And that is only for the English either in England or Wales but the regulations have not followed the regulations and have not been published in Welsh so may not be valid in Wales! At least for Welsh speakers!
Eric

 

[Conan325]

Thanks for the advice guys. I might have to use a professional then. However, as I live in Scotland, Part P will not apply, and in my reading of the requirements for a building warrant in Scotland, it would seem there is no requirement to inform the local building control either.

 

[Space cat]

Because outside lights have a hard life, I like to put them on their own fuse and my preferred method is a dedicated breaker in the CU or an FCU off a ring - with a neon so I know whether it's on or not. That way, a fault in the outside wiring won't take out all the other lights on the circuit.

Also, are you talking ordinary light bulbs here or halogen floodlights? A halogen lamp can draw a very heavy current when it blows so you can be sure that all your lights will go out if it's not on its own fuse.

In your case I can see that you might want the new switch to be in the same box as the existing one so you'll need to take power from the same circuit. If you don't mind having a bigger box, grid switches will allow you to put a fuse in alongside the switch and also a neon if you want one but --

This will only help if you have an old-fashioned CU with wired fuses. I find that a 6 amp breaker will trip faster than a 3 amp fuse can blow so you would still lose all the lights on the circuit if the outside one failed.

 

[Conan325]

The house is only 14 years old so is fitted with circuit breakers. I only intend fitting ordinary bulbs, probably of the low energy variety. The side of the house at the kitchen door is the only side the builder did not fit outside lights and leads onto the driveway. My thinking was fitting the lights on this side with the switch just inside the kitchen door for easy access, hense the reason I thought changing the existing light switch to accomodate the new cable.

 

[Space cat]

The house is only 14 years old so is fitted with circuit breakers.

Ok, so no advantage to a fuse in a gridswitch. The breaker would go first.

I only intend fitting ordinary bulbs, probably of the low energy variety.

So the breaker is no more (or less) likely to trip than it would if an inside bulb popped.

If you use good quality outdoor light fittings and put any outside cable in heavy duty PVC conduit you shouldn't have any trouble. Wire it as ericmark and Breezer have described. If you want to use a standard two-gang switch you'll need a piece of choc block to join the neutrals. Before you start, make sure you have room in the back box for all the extra wiring.

PS: As it happens, I do have one outside light wired straight into a lighting circuit. Its cable goes directly through the wall behind the fitting and it's wired in parallel with an inside light so I can see when it's on.

 

[Conan325]

Thanks for that