DIY Doctor

Beginner Rewiring a Light Fitting that's a Basic Radial Loop System

Postby Bouchehog » Sun Jun 21, 2015 6:34 pm

Hey there guys. Apologies for the beginners' question but I've been thrown a little by the way the loop has been wired in my house and wondered whether someone out there could help.

I'm trying to replace four light fittings with this POS from B&Q:

I seem to have a basic radial / loop system with two lights to one switch. The old light fitting had a decent block system for the wiring. Here's a photo of the old slaved light:

What's throwing me is the way that the loop and switch has been wired in. Here's the wiring in question:

It seems a standard colouring scheme with the earth as the green/yellow, Neutral as blue and Live/Line as Brown. I assume that the two sets on the left are my lines to and from the next ceiling rose. The other two sets, in which the Earthing lines have been joined and one of the Neutrals has been sheathed in a live jacket is thowing me. Here's a better shot of those six wires:

I presume that the jacketed neutral wire should be wired into the live circuit as part of the switch but I would appreciate some guidance!

The second issue is that the B&Q lights come with a tiny, cheap plastic 3-way terminal block for the new wiring, like this:
10A-3-Way-H-Type-Plastic-Terminal-Block.jpg (27.94 KiB) Viewed 824 times

There's no way that I could physically fit five live wires plus a sixth for the actual light fitting into that block. There is an extension piece for a loop but I have no idea which wires then need to be together. Is there an easy solution to this? Should I be buying a better terminal block to make life easier? There does seem to be room in the base for the light fitting:

Any/all help much appreciated!

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Simply Build It

Postby ericmark » Sat Jun 27, 2015 6:14 pm

1) Get some terminal strip.
2) blue or black is not always neutral.

In theroy when a blue core is used for line there should be a brown sleeve over the blue wire. In practice often this is not the case.

So one of the blue wires is actually switched line.

So three cables will likely be:-
Supply to lamp.
Supply to next lamp.
Wires to switch.
Your task is to work out which cable is wires to switch.
You need a four way connector block with the following:-
Permanent line
Switched line
The switched line is likely blue in colour.

I tried to give a system to test which wire was which but for my efforts I was thrown off the site as some one said my method was dangerous. So sorry not doing that again you have to work it out yourself.
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