Electric cable history

[Scott]

I saw former neighbours, who have moved house (address not stated for legal reasons).

She told me a full rewire is needed. According to the electrician, the cable is older than rubber cable [VIR, I assume]. My former neighbour describes it as cloth covered. I have asked for a sample to see what it is.

Personally speaking, at this point I would have pulled the main fuse.

Despite some Google searching, I cannot find details of the cable used before VIR (Vulcanised India Rubber). I seem to remember that paper may have been used. Could someone clarify? .

[Robin]

Lead sheathed came between paper and VIR.

It might be that they have cloth (Hessian?) covered VIR but it's ages since I saw any and I can't really recall what it's like.

[Clive Arthur]

Gutta-percha?

[Robin]

I should of course have known that the answer is to be found in

[Jack Harry Teesdale]

VIR came into general use in the early 1900's, prior to that cables were oil impregnated inner insulation with lead covered outer sheaths.

Cloth coverings would have been introduced to replace the lead to reduce cost.

VIR is not inherently dangerous but should be tested annually for insulation resistance and visual condition.

[Dave Plowman (News]

Fabric covered singles with, I assume, rubber insulation, used to be pretty common. Same thing was used for car wiring up until about 1960. Indeed, you can still buy it to restore old cars.

[John Rumm]

You quite often see PBJ (Poly Butyl Jute) insulated cables on things like meter tails.

e.g.:

The red/black tails are PBJ

[Scott]

Thanks. She is describing it as cloth, not rubber. I suspect she may be looking at it from the outside. My guess is VIR.

[Tim+]

How do you look at cable from the inside? An electron’s eye view? ;-)

Tim

[ARW]

Not sure what the red T&E is that is mentioned on that page.

There was a red double insulated single and earth around in the early

1970s - and it had the earth insulated with green/yellow (so the outer double insulation and the insulation around the live core were both red and you did not need earth sleeving.

The neutral at the time was a double insulated black cable cable with both the outer and inner sleeving being black over a single cable.

Only ever seen it in 1.5 and 1.0mm sizes.

I saw some today at a golf course that opened in 1974 - I swapped three of the DBs that were original (Crabtree C50's) whist a couple of other lads installed a new SWA supply to make it a nice new 3 phase DB.

They had no choice to swap them as it had several C1s when I inspected it and we have the power to disconnect.

becomes

Wonder what that cost them?

3 hours for two sparks and a reasonable 2nd year apprentice on Wednesday. But an hour of that was me showing them the run and access to the run and getting the kit in 9 hours for same again on Thursday. 5 hours for just the sparks on the Friday for the finishing touches.

Plus the kit.

35m of 25mm 4 core SWA plus tray and all round band etc. A 3 phase Hager DB with 18 RCBOs

[SH]

Wow... a Sangamo Electromechanical timer..... that takes me back at least 30 years!

[ARW]

It was still powered but not controlling anything. So I disconnected it.

I was still fitting them at Army housing back in 2016.

The Q551 is a brilliant piece of kit.

I very rarely see these fail.

[Tim+]

Have a old one in my garage. Looks useful for something. Just haven’t found a use yet. ;-)

Tim

[ARW]

I have a challenge for you and all other posters who have one.

Try wiring one up.

These are unknown monsters until you know them.

[Tim+]

I did once. The connections weren’t entirely intuitive I see to recall.

Tim

[SH]

piece of piss.....

Left hand terminal was live in

middle terminal was neutral (commoned to neutral in and neutral out)

third terminal was live out

The electricy board could apply a meter seal to seal the clear plastic cover to the black housing....

I also recall you could pull the electromechanical mechanism out of the housing.

They were quite popular for switching either dual rate meters or night storage heaters.

In my case, the Sangamo timer was used to power a vibrator in my bed...... as timed vibrators were not available in the 1980s and I needed something to make me rise up every morning.

[Scott]

Now they use AA batteries :-)

[John Armstrong]

In 1969 my parents moved to a house with off-peak heating. I remember there were two Sangamo timers at the distribution board. One was deeper front to back than the other, and you could pull the time switch off the (bakelite?) back which was screwed to the board and held the connections. They should have been sealed but weren't. I also remember that one made connection to the heaters via an "Enbray" contactor - something I've never seen before or since.

House was in Gourock, and Sangamo's factory is ten miles away in Port Glasgow.

[Brian Gaff]

Well, from what I recall, some of the rubber covered stuff also had a kind of fabric over the top. Certainly my old Grandmas house had that and it was of the age were the toilet was in the garden. Our house which was built in the 30s had some kind of e enhanced rubber covering that seemed not to have hardened and cracked with a satin feel to the fabric outer layer. Obviously it was all replaced by PVC. A lot of the cables that came out were just two wires and others were two wires and a bare earth. The circuit breakers were mostly just fuse wire except the immersion heater which was a simple cut out. Brian

[Brian Gaff]

Ha ha. I think there must have been more than one sort of rubber used, as some of it even today looks in remarkably good order when removed, while other seems to turn to little bits and crumbles when bent. Both came with fabric or no fabric. I've seen some of the wire that folk have stripped out over the years as I was always on the look out for wire. Interestingly when it came time to change our Cooker the wire was actually made of aluminium. Not sure why this was done though. Must have been done late 60s or so? Brian