Curious Wiring - Ideas?

[The Riff-Raff Element]

I'm tearing out some old wiring at the moment. It is the most curious stuff. It's very heavy. On the outside there is an insulating layer, as you might expect, then a lead sheath, another insulator, then two conducting cores each with another coloured insulator - one brown, one black. The cores themselves do not appear to be copper: I thought they might be tinned copper, but it appears to be a solid, white, metal.

I did wonder at aluminium, but I'd expect these to be thicker than copper and these look thinner than copper-core wire in similar use. Any ideas? Was silver ever cheap enough to be used in cabling? This stuff could have been here since the 1950s.

[Maykal]

A very very old system of wiring used a lead sheath as a kind of earth so it might be that system. They also used aluminium a lot in the past. The fact that they are thin might mean they date back a few years when basically the only electrics you had in the house was the lighting so thicker (typically 2.5mm now) wiring wasn't used.

In my house, which I've just rewired, all kinds of wiring was used. I think they just used whatever came to hand without worrying too much about thickness or colour coding. Some was way too thin for purpose, other stuff was over-speced - I guess it was just a case of them using whatever they could get on the cheap (or filch from work in some cases). The sockets were generally just spurred into the lighting circuit and the whole lot was on one old screw in fuse - yes, all the lights and sockets, and it's a big house with outhouses!

[The Riff-Raff Element]

Thanks for the reply. I've had another look at the conducting cores and they are tinned copper. So the lead sheath was an earthing system? The cabling is old, and like your place, the whole of the upstairs lighting & power sockets run off this single cable. There are fuses in the plug sockets and light switches. Apparently this is OK, but our electrician says any additions must come through new additions to the fuse board.

[Maykal]

I did a bit of googling and apparently there are other reasons for using lead sheathing to do with protection from elements - not frequently used in houses but if the cable was salvaged...

You'll probably be ok depending on what you're plugging into the sockets. If it's anything that draws a heavy current, then it'd be best to have a dedicated circuit. If it's a big place, it's also handy to break up the lighting and socket circuits to, say, 5 or 6 outputs per circuit. Not only does this reduce the risk of overloading, but if something does go wrong, you at least have light and power in other areas of the house. It's also a good idea to have dedicate circuits to the fuse box for things like AC, washing machine, water pump (if you're using well water), outdoor lighting and so on. The main thing that would worry me is whether the wiring is up to handling modern current loads. If it was meant for lighting then it's probably only 1.5mm wire or similar and if you start plugging kettles or irons or stuff into the sockets there is a risk.

From what you've said, it sounds like the wiring is buried in the plaster rather than running through conduit, right? Bit more of a pain to rewire. I had the same problem - apart from a few runs to the centre lights in rooms, the rest was plastered-in cable, which meant chasing out all the walls. There were even rooms which no electrics at all! In the end I put in 11 separate circuits: three for lighting, three for sockets, washing machine, pump, workshop, pump, exterior lighting. Quite a mammoth undertaking that took the best part of 9 days!

[The Riff-Raff Element]

It was a farm - house plus barn, which might explain why something over spec was used since there was originally a fair bit of stuff that was exposed to the elements. We know the house was rewired in 1953, which dates the current installation. The barn part is on a completely new and separate fuse board to the house, and that is where most of the duty is now. The work we're doing now will rewire the downstairs of the house completely and we'll be putting in a false ceiling - we'll add new sockets upstairs from there. All we'll have on the old circuit will be a few lights. I feel happier about this than the current set-up!

[Skippy]

I've come across this stuff many times in the past in old buildings. It seems to have been used where nowadays steel conduit is used. Over here scrapyards call it pencil lead but it's not liked much as the combination of materials (well the rubber mainly) make it a dirty stuff to recycle.


Pete