I need to sort out a cluster of electric cable sizes from my CU. I can't look at them and tell a 10mm2 from a 6 mm2 . I would assume that the size is determined by the actual copper core diameter but can't figure it from the info given or from the wire jacket size. Does anyone have a good way for an old fool that can't find the square root of zero much less figure 10mm2. Thanks all.
I just look at them, the ring main is 2.5mm, so a bit over twice is
6mm, 4 times is 10mm. The bigger ones have more strands in the core. 2.5 is workable, 6mm is a PITA, 10mm is no fun at all, it hurts your hands to work withWhen I am fitting, I look at the roll, to make sure ..........
Rick
Tangent ----->
Has the specification of copper used in cables got harder over the years (effectively a different carat rating) or does copper actually soften with time? I'd hope it wasn't softening due to annealing as I think copper needs 400C (especially as the earth was softer too)
I ask because the old meter tails and earth I recently removed (16mm and
10mm respectively) are noticibly easier to bend than present cable (I mean the actual conductor stripped of insulation). The old cable is probably original for the house (>30 years)As for the new 25mm^2 meter tails, well I've never used cable that's easier to push than pull before ...
You could always find some sample pieces of cables and measure the copper cores using a vernier gauge.
Dave
1 & 1.5mm^2 can be quite hard to tell apart from the outside. The rest are easy when you've got the hang of it. The following may be of use.
CSA (CPC) Strands Overall mm^2 No./dia. mm approx.
--------- ------- ----------
1.0 (1.0) 1/1.13 4.5 x 8.2 1.5 (1.0) 1/1.38 4.7 x 8.2 2.5 (1.5) 1/1.78* 5.3 x 9.9 4.0 (1.5) 7/0.85 6.1 x 11.4 6.0 (2.5) 7/1.04 6.8 x 13.1 10 (4.0) 7/1.35 8.4 x 16.8 16 (6.0) 7/1.71 9.6 x 19.5HTH
Jim wrote on 02/01/2005 :
Some samples of the various sizes against which to compare them, is a good place to start. Another way assuming you want to check via the outer grey plastic, is to check the fit of a plastic cable clip over the outer sheath of the cable. You might also find the grey outer sheath is marked with the cable size.
It would also be fairly safe to assume that 2x cables going into a 30 or 32amp MCB or fuse is a 2.5mm for a ring main.
Never assume anything until proven. Very poor advice.
Stephen Dawson pretended :
That is why I qualified it with the word 'fairly'!
a "fair bet" would be more like it, i wouldn't have mentioned the "s" word ...
I spent yesterday putting in 35mm tails ... now they are pretty hard on the hands .. and don't strip that easily either.
Rick
It could be that the old cables are not PVC .... PVC is not that flexible, especially on large sizes ... I speak from experience of running in 35mm yesterday. Years ago I did some jointing on big stuff (300, 500 mm2 etc. 2 ph, 5ph ...) .... PVC was a bitch to handle, but easy to terminate ... but oil impregnated paper insulated was great to handle ... your hands were as soft as a baby's bum afterwards.
Rick
No I stripped the old cable completely of insulation, so not that ...
35mm^2 is one of those sizes that seems to come in two different stranding options - 7/2.52 or 19/1.53. The latter is much easier to handle.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.