Old cable question

I was poking around under the floor of my mother's house sorting out the = wiring and I found that a socket that wasn't working was wired with twin = & earth cable with the normal grey PVC outer but the live and neutral = were 3 stranded multicore rather than the more normal single core. The = conductors (including the earth) were silver/gray rather than copper.

Does this cable date back to the time when copper prices went very high? = What kind of metal was used instead. Pretty certain it wasn't aluminum.

Tim

Reply to
Tim Downie
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Sounds like 3/029 or 3/036 tinned copper which was quite common in the 60's prior to metrication. That's 3 strands, each 0.029 or 0.036 inch diameter. I expect you'll see copper if you scrape the surface. They were rated at 10 and 15 amp each so I wouldn't have expected them to be used for a ring main but might have originally been a radial circuit feeding the old style 5A or

15A round pin plugs. The standard cable for ring mains was 7/029.
Reply to
Mike Clarke

more likely 3/029, which is an imperial size, and tinned copper conductors.

7/029 (2.9mm^2) was what was required for 30A ring circuits so it would be about 1.25mm^2 and not really up to standard.
Reply to
<me9

That is the predecessor of 1.5mm from before metrication. 3 strands of

0.029". Normally used for lighting or 5 amp sockets. 7/0.029 was the equivalent to 2.5mm. It was usually tin coated hence the bright appearance. Rather like good quality flex is.

Since it is PVC, rather than rubber, it could still be in satisfactory condition. But note the ratings above.

Reply to
Dave Plowman (News)

wiring and I found that a socket that wasn't working was wired with twin & = earth cable with the normal grey PVC outer but the live and neutral were 3 = stranded multicore rather than the more normal single core. =A0The conducto= rs (including the earth) were silver/gray rather than copper.

What kind of metal was used instead. =A0Pretty certain it wasn't aluminum.

As people have said, its older than that.

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you say wired with, if its just a single cable feeding a single socket then it should be adequate. But if there are 2 cables to the socket, either there are sockets daisy chained or its part of a ring circuit, and in either case the cable is well below what's required for a 30A circuit.

If it does turn out you have a 30A fused circuit wired with 10A or 15A cable, replacing the fuse with 10 or 15A would be a good idea - but if the circuit feeds the kitchen, it may be inadequate.

Some details of regs are of quite minor importance, but running 30A plus through 10A cable really isnt a good plan. It might do it, but its a fire risk.

NT

Reply to
Tabby

Thanks to all for the info. It was a single spurred socket that was wired up with the above cable at the socket end but the other end was hanging free near a junction box under the floor. Oddly, a new bit of 2.5mm cable had been loosely attached (looking like it was waiting to be pulled through) but the job never completed.

In the end all I had to do was complete the aborted job using the new cable and wire the spur into the junction box. (The existing ring was in 2.5mm).

Tim

Reply to
Tim Downie

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