Wiring for downlights

macadonald · 12 May 2011

Hi Guys,

Busy gutting and rebuilding my house. Last weekend I ran all the new lighting and socket cables (with guidance from an electrician). Although none of it has been connected yet, I need to put up some ceiling board and have had a slight change of ideas for lighting downstairs bu the front door.

I currently have a single twin and earth cable coming to the centre for the feed and a switch cable running from the same point down to where the switch will be. If I wanted to change the lighting in this area to 3 down lights, what should the layout be? Do I simply put a junction where the cable is now and extend 3 twin and earth cables to where the downlights will be, but leave the switch cable at the junction box?

Or with downlights being 12v (I think), do I run a smaller cable from the junction box? I assume the switch cable only needs to run to the junction box or the first downlight?

Thanks

riveralt · 12 May 2011

Given your proposals outlined here you really should stick to the advice given by your electrician.
He will be the one signing of your work and notiifying your Local Authority Building Control.
Any advice given here may be contrary to what he says, particularly as he has access to all the information needed to design the circuit - like cable sizes, earthing arrangements, protection devices, safe zones etc.

macadonald · 12 May 2011

Thanks and I completely agree. Just that he's away at the moment, so I was hoping that it was relatively straight forward. From reading other forums, it looks like what I thought is correct. I.e. a junction box at teh existing feed and then 1mm twin and earth cables runnign to each downlight.

What I never mentioned was that I will also have the feed for the next light in the circuit running out of that junction box.

riveralt · 12 May 2011

macadonald said:
Thanks and I completely agree. Just that he's away at the moment, so I was hoping that it was relatively straight forward. From reading other forums, it looks like what I thought is correct. I.e. a junction box at teh existing feed and then 1mm twin and earth cables runnign to each downlight.

What I never mentioned was that I will also have the feed for the next light in the circuit running out of that junction box.

Then really you should wait until he returns - as you WILL NOT get a EIC from him otherwise.
By way of example of your lack of knowledge is that JB's are not allowed unless they are accessible at all times.

Meanwhile read up here
//www.diynot.com/wiki/electrics:part_p
//www.diynot.com/wiki/electrics:lighting

ban-all-sheds · 12 May 2011

riveralt said:
Then really you should wait until he returns - as you WILL NOT get a EIC from him otherwise.

And even if he does, an EIC is all he'll get.

macadonald said:
there is lots of other notifiable work going on. All being done by myself so far. I've chased all the new sockets and conduit and have an electrician mate coming to rewire and connect everything in 2 weeks. He works on commercial installations with 15 yrs experience and is not qualified to sign it off, but I will pay a sparky to come and inspect and sign off.

macadonald · 12 May 2011

That's one hell of a memory ban-all-sheds, if you remember that post..

The good news is that the friend who gave me advise on running the cables is not the same that will now come and connect. The connections will be done by someone that is apparently part p qualified, which I believe means he is able to connect and sign the job off.

Back to the original question, which has been avoided - just managed to speak to the sparky, who has told me to run a twin core from the initial downlight that already has a feed to the next downlight and then another cable from that downlight to the 3rd downlight..

Just thought I'd post the result in case anyone else is ever searching on the topic.

riveralt · 12 May 2011

macadonald said:
Back to the original question, which has been avoided - just managed to speak to the sparky, who has told me to run a twin core from the initial downlight that already has a feed to the next downlight and then another cable from that downlight to the 3rd downlight.

Just make sure you run them in parallel and not series.

macadonald · 12 May 2011

Riveralt,

For my own benefit and simply to learn, can you explain the difference between running these in parallel rather than series (in terms of running the cable?

Is one downlight to the next parallel/series and the way they are wired what makes the dif?

Thanks

riveralt · 12 May 2011

macadonald said:
Riveralt,

For my own benefit and simply to learn, can you explain the difference between running these in parallel rather than series (in terms of running the cable?

This explains the difference..
http://www.flameport.com/electric/l...ing_error.cs4?124O13598807841103O9689726639=0

Courtesy of flameport - its probably worth starting from his home page.

diynot

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Wiring for downlights

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