Steel braided PVC cables found in an Airey house.
Anyone seen it before?
Is that a wire braid outside? The insulation looks a bit like rubber rather than PVC, which suggests it might be pre-WW2?
"In the 1930?s the first trials with PVC insulations were being made in Germany and by the end of the second world war there were significant varieties of synthetic rubbers and polyethylene.
By the 1950?s PVC was commercially viable and replaced rubber cables in many areas particularly in domestic wiring, aluminium was also starting to be used widely as an alternative conductor"
Steel braiding over single PVC insulated cores.
Possible, in a mining area?
Alternatively, no outer sheathing saved plastic (in short supply) and the steel braiding saved copper (in short supply), and steel (in short supply) compared to conduit, and was quicker to install than conduit.
Owain
I was here
Industrial / mining certainly sounds plausible. Might it even have been for firing explosives? The braiding might help reduce "losses".
Very close to here then
As you said an Airey type house. They were built as in kit form including the wiring. Each socket was radially fed with each cable being having different colour pairs. The braiding was the earth return path.
Is it steel or tin plated copper?
GH
Yes when we rewired in the 70s the old cable was mostly rubber with a kind of fabric on the outside. The cooker supply here is aluminium wire, and it seems to be pretty good, still, but of course dates back to the 60s, and was merely moved to the new CU when the rewiring was done. I've never bothered with another CU to bring it all up to date, since it seems pretty pointless these days. Brian
In our last house built 1957 it must have been wired with rubber insulated cable with a separate bare earth conductor running alongside it. I say must have because I only found one section connecting the bedrooms and if I recall right it seemed a lot bulkier than 2.5 T&E. I have no idea what types of sockets were there originally but there was evidence of wires being crimped to the earth conductor. The previous wankers - sorry owners, did a partial rewire if you could call it that hanging individual sockets off the rubber cable with junction boxes and as for the earth simply twisted the CPC from the new sections of T&E onto the old earth no crimps or solder and they did not even clean off the years of crud built up on the wire surface. I do not even to this day know if that section of rubber wire was even part of a ring main. In the end I started from scratch simply ripping everything out.
Coming back to the unfamiliar cable theme I came across a type of cable I had never seen before whilst re-plastering a wall it had two rubber sheathed conductors but they had an outer sheath of lead. It was only a short section I suspect to connect to a wall light. I presume the outer lead sheathing was to provide an earth conductor but it struck me as a very expensive cable especially for the fifties when we had just recently come off rationing following the war!
Richard
They didn't bother with earthing for lights in those days! Lead was to provide weatherproofing and also to keep ozone away from the rubber, which would otherwise crack. It also means a live to neutral fault should blow the fuse with little risk of causing a local fire.
My first house (Victorian) was built with gas lights, but electric lighting was probably added about 1910. This was via wooden trunking with two channels, each containing a single core rubber insulated flex. No two way switching in those days. Still functioning when I moved in (mid 1970's).
Pretty sure it is steel braiding. Just like a SY cable without the clear plastic outer.
Tricky Dicky expressed precisely :
That would have been 7.029 old imperial cable.
newshound was thinking very hard :
'Cap and casing', often installed by joiners who would wire houses up after a bit of basic training, in the 1900's on.
Makes some sense. After all, making a neat job of installing electrics to an old house not built with it needs more joiner's skills than electrical.
Didn't ally really appear due to the copper crisis when Rhodesia went independent? Although councils seemed to be always looking out to save a few pennies on their own house wiring.
I presume you meant this
I did.
Owain
The apprentice liked the joists. No need (or indeed no way) to drill them.
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