Mystery grey wire in UK light switch

[Alex Pollitt]

I've just moved into a new house (new for me, quite old actually) and am trying to understand the current electrical wiring. As part of this I opened up one of the existing light switches to take a look. It's a two gang switch, with the left switch being a 2-way and the right switch being a single/local switch. There are two white sheaths of wires, both with red, black, and green/yellow. These are wired up as I would expect and I understand what each of them is. But there is also a separate grey wire which is not connected to anything. Any ideas for what this is or how I can safely find out? I'm wondering if it's a neutral, but am not aware of that having been a convention in the UK?

 

[crystal ball]

Its a single sheathed cable , popular in the 60s 70s often for two way switching, it may have been part of a two way set up but now disused, the other end may be in a JB or another switch

 

[sparxxxx]

Its a single sheathed cable , popular in the 60s 70s

But only up north. Many many years ago I saw single sheathed on a display in a southern wholesalers. I asked do you stock it or sell it, he said "no one has ever asked for it"

Alex, where is the house? I bet he says south coast, hahahahaha

 

[Alex Pollitt]

The house is in Sheffield.

So it sounds like this wire is probably not connected to anything at either end, and is likely useless today. I had hoped I might get lucky and find it was a neutral wire, which would have been great for smart lighting, but thought that was pretty unlikely given the age of the wiring.

 

[xm77]

Seen single core and earth used in two way switching in a house built in 1990: Wales

 

[sparxxxx]

Seen single core and earth used in two way switching in a house built in 1990: Wales

North Wales

 

[333rocky333]

What colour is it.
The other end may be behind the light

 

[echoes]

The house is in Sheffield

I remember finding yards and yards of single core cable when I rewired a house that I owned in Sheffield.
Lights didn't have earths either.

 

[RF Lighting]

My wholesaler still keeps it on the shelf in both PVC and LSF varieties. It was the most common domestic wiring type around here but seems to have fallen out of favour in the last 20 years.

 

[bernardgreen]

Talk of houses wired with single core wiring reminded me of this unusual way to wire a house.

https://www.diynot.com/diy/threads/purple-haze-diy.413843/

At the time I was told the cores were identified by coloured threads, I was later told they all had paper sleeves with the wire numbering written on them

 

[SUNRAY]

Talk of houses wired with single core wiring reminded me of this unusual way to wire a house.

https://www.diynot.com/diy/threads/purple-haze-diy.413843/

At the time I was told the cores were identified by coloured threads, I was later told they all had paper sleeves with the wire numbering written on them

I've worked in old panels where wires were identified by printed paper sleeves and some of the practices in valve equipment use silk lashings to stabilise the ends of silk insulated wires before wax applied and using coloured silk to identify wires in bundles.
I have encountered a house wire in all white wires identified with red, green and black, either sleeves or something like paint or marker pen. and another where the whole of a circuit is identified with a single colour related to the fuse carrier colour, ie L, N, & E wired in white for a 5A fuse.
I've also worked on a car which had a replacement loom after a fire all done in different sized whites.

 

[Alex Pollitt]

The other end of the two-way switch also had a single core gray cable. This one must be wired to the light. But what the gray cable in the other switch (that I originally asked about) was intended for is a mystery to me. I guess one day I will find out if I ever end up needing to do any work at the light end of the circuit.

 

[333rocky333]

The other end of the two-way switch also had a single core gray cable. This one must be wired to the light. But what the gray cable in the other switch (that I originally asked about) was intended for is a mystery to me. I guess one day I will find out if I ever end up needing to do any work at the light end of the circuit.

The colour should give you a clue what it was intended for, its not the Grey thats just the sheathing the main core colour is beneath that and visible looking end on.

 

[Alex Pollitt]

It's a single core cable. It doesn't have separate outer and inner sheathing.

 

[333rocky333]

It's a single core cable. It doesn't have separate outer and inner sheathing.

Sorry to doubt you, but thats extremely unlikely