How Old is Copper Clad Aluminium etc

[Marcus Vaughan]

Hi All,

I'm part way through testing an empty old house with all sorts of older wiring and a 3036 board in order to work out whats needed.

First circuit is copper clad aluminium ring final. I measured one of the strands and have it as 7/036.

Question - am I wrong to assume is imperial?

I do not know when this was commonly used/installed.

In fact I had a decent document or web page once which gave a kind of history of UK wiring with dates etc. - but I can't find it. Has anyone got anything useful?

I need to investigate this particular circuit further as IR for LN = 26 Mohms despite the house being empty, LE and NE at just other 100Mohms so maybe rewiring anyway.

Pictures because we all like pictures, from right to left - circuit 1 is copper clad ring, circuit 2 is copper clad ring mentioned with low IR. Lights are copper - but not sure about the last two yet.

 

[SJD]

I need to investigate this particular circuit further as IR for LN = 26 Mohms despite the house being empty, LE and NE at just other 100Mohms so maybe rewiring anyway.

Not sure why you'd be considering rewiring with an IR of 26 MOhm or 100 MOhm, these are not too bad (for old wiring).

 

[westward10]

From the green sleeving early seventies. Copperclad T&E was normally 1.5 solid or 4.0 stranded. Very few accessories or distribution boards have suitable terminals for the connection of those conductors. Essentially unless they can be terminated correctly it should be rewired.

 

[Dave OCD]

Marcus - I may be wrong but I'm 99% sure the cables you refer to will be imperial sized tinned copper conductors. This type of old cable seems to go on forever in my experience and I'd also suggest the IR readings aren't bad at all !

 

[Marcus Vaughan]

Not sure why you'd be considering rewiring with an IR of 26 MOhm or 100 MOhm, these are not too bad (for old wiring).

Interesting response. I thought it was a bit low. Truth is there are other reasons to rewire anyway, such as not enough sockets and they are all in skirting boards, the floor area for a single ring is a little too big according to guidance as it goes over 3 floors and includes the kitchen, it's an ideal time because the house is empty etc.

But thank you.

 

[Marcus Vaughan]

Marcus - I may be wrong but I'm 99% sure the cables you refer to will be imperial sized tinned copper conductors. This type of old cable seems to go on forever in my experience and I'd also suggest the IR readings aren't bad at all !

OK - another vote for IR not being too bad.
Aluminium is definitely on the inside though, you could scrape the copper of with a knife to see it. Not too easy to get a photo of!

 

[SJD]

Interesting response. I thought it was a bit low. Truth is there are other reasons to rewire anyway, such as not enough sockets and they are all in skirting boards, the floor area for a single ring is a little too big according to guidance as it goes over 3 floors and includes the kitchen, it's an ideal time because the house is empty etc.

Fair enough if there are other reasons. E.g. sometimes when there is only 1 socket per bedroom and you need 3 or 4 per room, it is simpler to start again with a new circuit.

 

[Marcus Vaughan]

From the green sleeving early seventies. Copperclad T&E was normally 1.5 solid or 4.0 stranded. Very few accessories or distribution boards have suitable terminals for the connection of those conductors. Essentially unless they can be terminated correctly it should be rewired.

Thank you. I was thinking early seventies. The adjacent lighting circuits are 1.5/1.0 copper so it seems a strange mix. Partial rewire or what was available at the time. Who knows. I do know that I had a real struggle getting those conductors (neutrals) back into their terminations just because of their size (and quantity).

 

[Lucien Nunes]

As per Westy probably 4mm² from the early 70s. You would want the 1970 or later metric version of the 14th edition to look up its specs. Agreed that terminations are its downfall. Better than bare ali, because the copper cladding prevents the oxide formation that makes even mechanically sound ali connections go high-resistance, but not as good as copper because it's soft and easily crushed by terminal screws.

There were accessories made specifically for it. MK sockets of the era, for example, with a kind of wide cage-clamp terminal with a flat pressure plate instead of the end of a screw. Will be interesting to know whether these were used in this install.

If you have a mix of 1.0 and 1.5mm² on the lighting, check that the 1.5 isn't copper-clad ali. AFAIK that was the smallest size made, or at least it was necessary to use 1.5 for lighting and 4.0 for RFCs because of its lower conductivity than copper.

 

[Dave OCD]

Two red meter tails as well, that would annoy me.
I'm still not convinced it's aluminium though- no offence intended !