Michael,

On Thu, 11 Aug 2005 13:51:52 +0100, Michael Rigby-Jones wrote:

>...<
> No, all fixed wiring is solid core in the UK (known as "twin and earth").  Stranded wiring is only use for 
appliance "flex"

Not quite true, I'm afraid!  The *commonly used* twin & earth cables are solid core, up to 2.5mm^2 - above 
that (4, 6, 10, 16, 25mm^2) they are normally 7-strand.  Granted that it's usual to wire lighting in 1 or 
1.5mm^2 and power rings in 2.5mm^2, but things like electric showers need 6 or 10mm^2, and sometimes there is 
a reason (voltage drop, usually) to use 4mm^2 for power rings as well.

But actually the above is just the commonly available versions - you can get different strandings if you 
search hard and are willing to pay more.  I have some 6mm^2 earth cable that has 84 strands, and it's much 
easier to bend when you're working in confined spaces.  Trickier to strip and clamp without damaging the 
strands, but excellent to crimp!

Back before we "went metric" with cables, the standard twin & earth for power rings was called "7/029", 
because it had seven strands that were 0.029" in diameter - my house still has some of this!  The earth core 
was 3/029, and a right pain it is to work with, especially when trying to get a number of wires into a single 
earth clamp.  7 strands form a decent circle, but getting several "triangles" to cooperate is quite a juggling 
act.

Cheers,


Howard Winter
St.Albans, Herts


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