Help with wiring please

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hardcastlephil

Original Poster:

351 posts

161 months

Thursday 19th January 2017
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Good evening,

I was hoping for some simple wiring advice. We're currently renovating our house and one of the jobs is to remove the cabling from the outside. Lots is sky/old tv etc. but one line is power to an outside light. The power comes from the back of a socket on the 1st floor to some kind of fused spur box. From then it runs right round the outside of the house (in a lovely light gray which is very obvious) before dropping down to 1st floor switch height - through the wall to the switch then back out again before continuing round the house to the outside light. The pic below might help a little - it's the power line in blue. It looks even more of a mess in real life!



I was going to just remove the wire and do without a light as we don't use that door, but Mrs. H has now suggested that she would like a light still. We're just about to decorate the front hall so best to do anything before than after!

My question is - could I go from the 1st floor above the entrance hall and take power from the light in there (Red switch and light on my pic), chase it down the wall to the switch, back up the wall and then out at floor joist level to the front where the light is. The house was re-wired circa 2002 - will there be a constant supply at the light in the entrance hall?

Sorry for what may be an obvious question. I'm happy to do the donkey work then get a spark in to wire it all - I just need to know if it's possible before I start the decorating! If it is I can't understand why the electricians didn't just do it first time around. We've got the same issue at the back of the house.

Cheers, Phil



CaptainSlow

13,179 posts

211 months

Thursday 19th January 2017
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I suspect there will be a junction box near by. The red light will have an earth and neutral to the junction box and a switched live to the switch. The switch will have a perm live to to the junction box. The junction box will have all three to the ring. I think.

Ian Geary

4,462 posts

191 months

Thursday 19th January 2017
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I'm not an electrician, but doesn't it depend how the light circuit has been set up?

The red switch would have to have constant power, but one would need to look at the wires entering the red lamp holder to see if it was also acting as a 'junction box' for the circuit.

It is odd someone has gone to the expense of running a cable all that way if there was an existing light so close.

Ian


Cerbhd

338 posts

90 months

Friday 20th January 2017
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You'll need to remove the light to see if you have a permanent feed there, if you do then it's easy.
If not how about removing the existing porch light switch and shorting out to give a permanent feed to the light and fitting a light with a built in PIR? You could then fit a new outside light either via the switch or a PIR (or both)
Or run a 3 core and earth from the existing hall light switch to achieve the above but with the added benefit of an internal over-ride for the porch?

Mr Pointy

11,147 posts

158 months

Friday 20th January 2017
quotequote all
As others have indicated you need to check if there a permanent live in the ceiling rose of the red light in your drawing. This is where you would pick up the supply for the external light, not the red switch. Here's an example of how the red light/switch should be wired - note the first one shows red/black for the lighting circuit core colours, the second one you can select old or new colours on the left:

http://www.diydata.com/planning/electric_lights/el...
http://www.lightwiring.co.uk/multi-point-radial-li...

hardcastlephil

Original Poster:

351 posts

161 months

Friday 20th January 2017
quotequote all

Evening - thanks very much for all the replies.

I was hoping this would be the case - I'll have a look tomorrow at the light and see what's there.

At least it means I can start chasing a channel from the switch now before decorating!

Cheers,

Phil