CCC of old stranded wires

[a-z electrics]

Is there a CCC comparison table for old stranded wires anywhere?
I have a domestic installation, about 40 - 50 years old I wd say, and there are only 4 circuits, one is the sockets, with 2 wires into a 3036 30A fuse. I assumed it was a ring but it isnt, its not connected. The break is between the kitchen and rest of the house and theres been a kitchen conversion done, so Im assuming the fitter has bodged the wiring in a junction box somewhere. But is it possible its 2 radials, 1 for kitchen and 1 for the rest? The wire is 7 strand silver colour, so aluminium? but elsewhere in sockets there is a mixture of stranded and solid red and black.
I havent got the means currently to measure each strand (im going to get a micrometer, any suggestions from where?) but the overall wire size compared to a solid 2.5mm does look bigger.
The customer has had no fuse blowing problems (there again he probably wouldnt) but I told him it looks like the ring has been broken and needs re-connecting but I need to check...

The largest R1R2 reading on the circuit is 0.72 ohm and the largest Zs is 1.09.. phew! Ive fitted a dual rcd box, put the two socket wires into one 32A fuse as before temporarily and there are no problems on test results, apart from obviously no ring. No signs of charring at wire terminations either..

 

[Pete999]

Not necessarily Aluminum, probably 7/029 (2.5mm) or 7/036 (4mm) Cu cable

 

[a-z electrics]

Not necessarily Aluminum, probably 7/029 (2.5mm) or 7/036 (4mm) Cu cable

and what are the CCCs of these two sizes please? or is there a table somewhere?

 

[Pete999]

and what are the CCCs of these two sizes please? or is there a table somewhere?

Saw one somewhere but can't recall where, the 7/029 relates to 7 strands 0f Cu wire .029 inch in dia think thats the correct description as foe ccc about 30A used in rings in those days, thinks this may help

http://www.electriciansforums.co.uk/newattachment.php?do=assetmanager&values[p]=1140791&editpost=1&contenttypeid=1&poststarttime=1446112060&posthash=ba0ec9a3cfca6a5d97d396a2330f98e3&insertinline=1
Sorry can't send the PDF for some reason Comparison of imperial and metric conductor sizes, google DAE comparison of metric and imperial conductor sizes

 

[Andy78]

and what are the CCCs of these two sizes please? or is there a table somewhere?

You'll be needing an old copy of the regs for that one if you cant find it online. Maybe a forum member will be along to oblige shortly, I know a few have old copies for reference.

 

[tony mc]

This might help taken from a post a few years ago

Not sure if it has copied View attachment Imperial cable ratings.pdf

 

[Richard Burns]

This table will probably not come out well but it does a comparison similar to the above.

Imperial	Metric
Imperial size strands / thousandths	Csa of Imperial Conductor	Csa of Metric Conductor	CCC 14[SUP]th[/SUP] Edition 1966 Clipped direct Close protection, 25°C
in	mm[SUP]2[/SUP]	mm[SUP]2[/SUP]	A
1/.044	0.98	1	16
3/.029	1.29		20
3/.036	1.94	1.5	25
		2.5
7/.029	2.9		29
		4
7/.036	4.52		40
7/.044	6.45	6	48
7/.052	9.4	10	60
7/.064	14.5	16	79
19/.044	19.4		82
19/.052	25.5	25	98
19/.064	38.7	35	130

 

[a-z electrics]

This might help taken from a post a few years ago

Not sure if it has copied View attachment 30512

Yes that had copied. Thanks.. I'll go get myself a micrometer and measure.. Could be two radials then and not a ring like I thought..

 

[a-z electrics]

This table will probably not come out well but it does a comparison similar to the above.
That is very useful .. Especially for someone like me who hasn't been brought up on the old imperial sizes, many thanks.

Imperial	Metric
Imperial size strands / thousandths	Csa of Imperial Conductor	Csa of Metric Conductor	CCC 14[SUP]th[/SUP] Edition 1966 Clipped direct Close protection, 25°C
in	mm[SUP]2[/SUP]	mm[SUP]2[/SUP]	A
1/.044	0.98	1	16
3/.029	1.29		20
3/.036	1.94	1.5	25
		2.5
7/.029	2.9		29
		4
7/.036	4.52		40
7/.044	6.45	6	48
7/.052	9.4	10	60
7/.064	14.5	16	79
19/.044	19.4		82
19/.052	25.5	25	98
19/.064	38.7	35	130

Thanks very much, this is very helpful to relative newcomers like myself..

 

[a-z electrics]

Not necessarily Aluminum, probably 7/029 (2.5mm) or 7/036 (4mm) Cu cable

How does one tell if its copper or aluminium? If its copper then it must be plated.. With tin?

 

[Lucien Nunes]

With tin?

Yes. Almost all imperial sizes of copper cable were tinned as standard, instead of being plain copper, and because it was so widespread almost all 'silver' coloured T+E found in the UK is copper. Aluminium was so rarely used that I am struggling to find any samples for the museum. It was more prevalent in the USA, although even there only for a few years at the end of the 60s and beginning of the 70s.

Al cables have a different sheen and feel to tinned copper - greyish rather than bright - and very soft. In a torch flame, the end of a small aluminium cable will soften and bend under its own weight while copper will glow red hot without giving way.

 

[shanky887614]

Is there a CCC comparison table for old stranded wires anywhere?
I have a domestic installation, about 40 - 50 years old I wd say, and there are only 4 circuits, one is the sockets, with 2 wires into a 3036 30A fuse. I assumed it was a ring but it isnt, its not connected. The break is between the kitchen and rest of the house and theres been a kitchen conversion done, so Im assuming the fitter has bodged the wiring in a junction box somewhere. But is it possible its 2 radials, 1 for kitchen and 1 for the rest? The wire is 7 strand silver colour, so aluminium? but elsewhere in sockets there is a mixture of stranded and solid red and black.
I havent got the means currently to measure each strand (im going to get a micrometer, any suggestions from where?) but the overall wire size compared to a solid 2.5mm does look bigger.
The customer has had no fuse blowing problems (there again he probably wouldnt) but I told him it looks like the ring has been broken and needs re-connecting but I need to check...

The largest R1R2 reading on the circuit is 0.72 ohm and the largest Zs is 1.09.. phew! Ive fitted a dual rcd box, put the two socket wires into one 32A fuse as before temporarily and there are no problems on test results, apart from obviously no ring. No signs of charring at wire terminations either..

not micrometer digital vernier calipers are your best bet.

you can get a cheap set for around £15 at halfords but dont expect them to be super accurate (i did measure 3.5mm pins etc and they were reasonably accurate the biggest problem is there plastic)


just spotted these and there a good buy, do metric and imperial

 

[uksparks]

I've got a link on my computer that tells you, actually it's a PDF from the 14th edition I think come to think of it.

 

[gnselectricals]

Yes. Almost all imperial sizes of copper cable were tinned as standard, instead of being plain copper, and because it was so widespread almost all 'silver' coloured T+E found in the UK is copper. Aluminium was so rarely used that I am struggling to find any samples for the museum. It was more prevalent in the USA, although even there only for a few years at the end of the 60s and beginning of the 70s.

Al cables have a different sheen and feel to tinned copper - greyish rather than bright - and very soft. In a torch flame, the end of a small aluminium cable will soften and bend under its own weight while copper will glow red hot without giving way.

I got a job in Swansea where I know there is at least 1mm equivalent Ali cable, stripped a bit out last year but still some in service. If I go back its yours

 

[a-z electrics]

Ordered a digital micrometer off ebay now, accurate to 0.001mm. Should be enough! Cost £25 delivered. Used to use these in my engineering days. (Not digital then though, calculators were just becoming big news! )
I think for this kind of measure you really need a micrometer to distinguish between such fine strands..