Could someone please explain how old lighting wiring works

macca · 14 Oct 2008

I'm fine with wiring lighting circuits using T&E but the old single wiring confuses me.
Recently i saw a light wired in the old singles cables with one red cable & 2 blacks, with the red connected to the live connection and the 2 blacks in the neutral. Now if the red it live, and one of the blacks is neutral what is the other black wire connected to the neutral and where is the switch wire?

securespark · 14 Oct 2008

Think you must be confused!

The single red would be the switchwire, and the neutrals a loop in & out.

macca · 14 Oct 2008

ok so if the red is switch live, the neutrals are neutral loops in and out so where is the phase loop in and out?

Steve · 14 Oct 2008

macca said:
ok so if the red is switch live, the neutrals are neutral loops in and out so where is the phase loop in and out?

At the switch

macca · 14 Oct 2008

i take it that at the switch then there will be a loop in and out at the common connection and the switch wire connected to L1 - is this how they used to do it?

Steve · 14 Oct 2008

macca said:
i take it that at the switch then there will be a loop in and out at the common connection and the switch wire connected to L1 - is this how they used to do it?

Maybe. I wouldnt know. But its the simplest / cheapest way to use single wiring, certainly.

macca · 14 Oct 2008

well at least it makes a bit more sense now!
prefer the modern way of looping in a out with all cables tho at the light tho!

bongos · 14 Oct 2008

macca said:
I'm fine with wiring lighting circuits using T&E but the old single wiring confuses me.

It confused me too when I discovered mine was the same a few months back. But it's like you describe - neutral loop at the lamp and phase loop at the switch with singles going all over in the attic. It's due replacing too

Steve · 14 Oct 2008

macca said:
well at least it makes a bit more sense now!
prefer the modern way of looping in a out with all cables tho at the light tho!

Why? It makes it harder to fit downlights, and other decorative lighting, which most of the time dont have enough terminals or space to terminate all the wiring up there.

You call it the modern way, yet this method has been used for 30+ years, and is being slowly discouraged as electricians are asked to fit more downlights and complex lighting, rather than ceiling roses. The method becoming more popular (and modern) is to loop in all cables at the switch, taking just the N and SL (and E) to the light.

Lectrician · 14 Oct 2008

Here is a crude pic.

Look at the top left light

RF Lighting · 14 Oct 2008

macca said:
is this how they used to do it?

It's how you still do it in alot of commercial properties

breezer · 14 Oct 2008

Its done like that becuse it also saves money since youonly have one core to run, unlike a twin and earth you have two (and earth) so in effect you are sving money on cable (but losing it on conduit)

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Could someone please explain how old lighting wiring works

breezer

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