UK light wiring

wallis2xk · Jun 13, 2021

Hi,

I'm trying to replace a light fitting and am unsure of the wiring here, which must be quite old. There was a red going into what I presume is earth, but then a double black wire and a single black wire. Are these Neutral and Live?

Thanks

timhoward · Jun 13, 2021

The three reds are all Live but shouldn't be connected to the light. They need enclosing in a terminal block or a wago connector.

The two blacks twisted together are neutrals and should be connected to the light.
The black on it's own will almost certainly be coming back from the switch and is the Switched Live. It should have red tape or sleeving around it but a lot out there don't. That is the Live feed to the light.

The greens are earth and should be connected to the earth terminal on the light by a single wire sleeved in yellow/green.

littlespark · Jun 13, 2021

Certainly, don’t use the earth terminal as anything other than the earth. A separate connector for the permanent live.

westward10 · Jun 13, 2021

The old fitting uses the third terminal as earth or loop, look carefully you can see it stamped and in your case it was used as a loop for the three reds. Personally I would get a complete new fitting which incorporates all terminals to the base unit, like this.

British General Straight HO Batten Lamp Holder Light Fitting BC 3" - Screwfix

Order online at Screwfix.com. Enclosed. Straight profile. Polycarbonate construction, pre-wired with PVC-insulated wires. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

wallis2xk · Jun 13, 2021

Thanks for the replies. @westward10 I have indeed got a new fitting which I put on the right of the photo with the casing removed. So is there any issue if I wire the new one the way it was before?
Reds -> Earth
Double Black -> Neutral
Black -> Live

westward10 · Jun 13, 2021

The reds should not go to that terminal as it is identified as earth. Can you show the rest of the new fitting.

wallis2xk · Jun 13, 2021

Yes, it's this one here: Arlec Batten Bayonet B22 Lamp Holder White - https://www.homebase.co.uk/arlec-batten-bayonet-b22-lamp-holder-white/12816305.html

Photo attached with it unscrewed.

westward10 · Jun 13, 2021

You need a different style like the one in my link above as it will have a base like this with all the required terminals.

[ElectriciansForums.net] UK light wiring

brianmoooore · Jun 13, 2021

wallis2xk said:
Yes, it's this one here: Arlec Batten Bayonet B22 Lamp Holder White - https://www.homebase.co.uk/arlec-batten-bayonet-b22-lamp-holder-white/12816305.html

Photo attached with it unscrewed.

How is this sort of outdated rubbish still allowed to be sold?

wallis2xk · Jun 13, 2021

@westward10 Ok thank you, I'll get one of those. Excuse my ignorance again, but just to clarify, the red wires could go into the terminal into the the old fitting because it could be used as loop whereas on the new one it can't be used as a loop?

westward10 · Jun 13, 2021

The old fitting is marked earth or loop the new one just earth so we cannot advise you use this terminal as the loop.

Lucien Nunes · Jun 13, 2021

Not all batten holders have that 3rd terminal but those that do, sometimes have it connected to the metal shell of the bayonet socket as a means of earthing (or at least, not thoroughly insulated from it.) Therefore, if the reds (permanent line loop-through) are connected to the terminal, it makes the metal cap of the lamp live to the touch, even with the switch off. The light works, of course, and you only find out when you happen to touch some earthed metal while changing the lamp. Some types of fitting have an isolated terminal that can be used for the line loop-through, but only if it is specifically marked as such, as your old one was. It is conventional to place the three red wires in a separate terminal (and the CPCs likewise if there is no earth terminal on the holder) but the enclosed type with terminals integrated into the backplate pictured by @westward10 is a much better idea all round.

brianmoooore · Jun 13, 2021

brianmoooore said:
How is this sort of outdated rubbish still allowed to be sold?

Probably should explain further for the OP.
It is not permitted to connect wires insulated with 'ordinary' PVC (as in your cables) directly to a lamp holder. The final connections should be by wires insulated with a high temperature resistant plastic, such as the short blue and brown wires on the one in westward10s pic.