Red & green twin (strange)

JohnW2 · 11 May 2021

sparkwright said:
Come to think of it, I think the old imperial lighting wires did have three strands.

Indeed, as I said, I thing 3/0.029" was the norm for lighting.

sparkwright said:
Presumably the old switch drops would consist of two or three of these red and green cables. I don't think blacks or neutrals were brought to the switch, particularly around the 1960s as suggested.

True, I should not have mentioned black - they would probably both have been red.

sparkwright said:
As I understand it, the red is sheathed and insulated, the green in only insulated, and two are 'stuck together' sort of thing.

Fair enough - so you're suggesting that 'switch drop' consisted of two separate cables, each consisting of an insulated-and-sleeved red 'stuck to' a green-insulated CPC? ... but did lighting cables actually have CPCs at that point in history?

Kind Regards, John

sparkymarka · 11 May 2021

The cable seems quite good condition, I’ve never seen this type before …

sparkwright · 11 May 2021

JohnW2 said:
Indeed, as I said, I thing 3/0.029" was the norm for lighting.
True, I should not have mentioned black - they would probably both have been red.
Fair enough - so you're suggesting that 'switch drop' consisted of two separate cables, each consisting of an insulated-and-sleeved red 'stuck to' a green-insulated CPC? ... but did lighting cables actually have CPCs at that point in history?

Kind Regards, John

See my previous edited post regarding the neutrals.

Typically three reds at the switch - feed in, feed out, switch live.

End of line would have two reds at the switch.

Sheathed and insulated neutrals (with no earth usually) running to the lights.

After 1966 there would have been earths, so this could be just after 1966ish.

Before 1966 it wasn't unheard of for lighting circuits to have an earth conductor in them, particularly if 5 amp sockets were used for lighting. The earth may not have been constant through the entire circuit though.

JohnW2 · 11 May 2021

sparkwright said:
See my previous edited post regarding the neutrals. Typically three reds at the switch - feed in, feed out, switch live. End of line would have two reds at the switch. Sheathed and insulated neutrals (with no earth usually) running to the lights.

Thanks for clarifying

sparkwright said:
After 1966 there would have been earths, so this could be just after 1966ish. .... Before 1966 it wasn't unheard of for lighting circuits to have an earth conductor in them, particularly if 5 amp sockets were used for lighting. The earth may not have been constant through the entire circuit though.

Indeed. In some of the ancient (certainly pre-1960s) bits of wiring I inherited in my house (but not still in-service by then!), it seems that at least some parts of some of the lighting circuits had 'earths' (for whatever reason). L, S/L and N were generally VIR singles, but often with a separate totally bare 'earth' running alongside. Mind you, it seems that the 'power' circuits also had a similar bare separate 'earth'.

Kind Regards, John

sparkwright · 11 May 2021

In the 50s properties sometimes had their lighting wired in the early pvc T+E, and the bare earths were simply twisted together and poked up in the ceiling void. Often the earth was not used for anything, regardless if metal light fittings were used or not.

Or sometimes the earths were just cut off.

Nothing was particularly black and white about wiring methods then.

Other houses in the 50s had their sockets wired in 2 core twin early pvc cable, with a bare stranded earthed cable run next to it.

In those days you used what you had, it seems.

JohnW2 · 11 May 2021

sparkwright said:
Other houses in the 50s had their sockets wired in 2 core twin early pvc cable, with a bare stranded earthed cable run next to it. .... In those days you used what you had, it seems.

Yes, as I said, the remnants of sockets wiring here seemed to mainly have a bare (stranded) 'earth' wire alongside (often stapled in place) - and I think they may well have been steel - certainly something far tougher (more difficult to cut!) than copper.

Kind Regards, John

sparkwright · 11 May 2021

Steel sounds familiar.

sparkwright · 11 May 2021

You know, it makes me wonder if in 1966 the cable companies may have had large supplies of red sheathed and insulated single core that they had no hope of selling, and simply 'welded' a single insulated green earth core to it...

JohnW2 · 11 May 2021

sparkwright said:
You know, it makes me wonder if in 1966 the cable companies may have had large supplies of red sheathed and insulated single core that they had no hope of selling, and simply 'welded' a single insulated green earth core to it...

That would make sense.

Kind Regards, John

winston1 · 11 May 2021

JohnW2 said:
Indeed, as I said, I thing 3/0.029" was the norm for lighting.

Except when they used 1/0.044" as I found in my 1930s house.

JohnW2 · 11 May 2021

winston1 said:
Except when they used 1/0.044" as I found in my 1930s house.

Indeed, and presumably closer to your heart given that it was close to 1mm², whereas 3/0.029" was nearer to 1.5mm²!

SUNRAY · 11 May 2021

sparkymarka said:
Seen this today 1960s house been rewired this is the old cable for the switch drops ....View attachment 233316 View attachment 233317

Not sure why I haven't seen this thread before.
That's the old 3/0.029 single and earth. Different makes did it either like your picture or more commonly like T&E;

By the way don't use this method to wire lights.

securespark · 12 May 2021

I have seen that cable before a couple of times, the one with the CPC attached.

Odd stuff.

JohnW2 · 12 May 2021

securespark said:
I have seen that cable before a couple of times, the one with the CPC attached. Odd stuff.

Sparkwright's suggestion sounds pretty credible - that, come ~1966 some manufacturers had lots of insulated-and-sleeved singles for which there was little continuing market, so they stuck green-insulated CPCs on the side to turn them into something more 'saleable'?

Kind Regards, John

securespark · 12 May 2021

I'm not so sure.

I&S cables, both with and without CPC, were commonly used well into the 1980s.

This coincides with the very last installations done under the 14th.

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Red & green twin (strange)

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