Products > Dodgy Technology

Is the market flooded with fake dangerous solar cable

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robint:
I have taken delivery of samples of TUV solar cables 6mm2 from EB. I was curious to know if these conformed to the specs. Correct me if I am wrong but we should have tinned Cu annealed wire 0.3mm dia x 84 strands. This gives 5.94mm2 thats ok for 70A. according to TUV specs

 The samples I got
a) looked genuine printed on the outside "6 sqmm DUCAB C BICC PV cable 1.5kV but it had 84 x 0.25 dia core = 4.124mm2
b) unmarked plain black pvc with inner white sheath 84 x 0.22mm dia strands = 3.193mm2

Both seemed to have stiff strands (IMHO not annealed (springy) hence potentially fragile especially round crimp connections - soldered? flapping in the wind when not fully secured)

Clearly a very important discrepancy

Before I go Nuclear with the suppliers, has anyone else noticed this issue as I took one look at the cable construction and immediately thought that its an obvious area for cheating.

I think you will agree that a 40 -50% undersized cable is a cause for concern

coppercone2:
well if they change the diameter of the inner strand without increasing the strand count its clear fraud. You could increase strand count to get a different more flexible cable, with slightly lower ampacity, and slightly different crimping parameters.

A single strand has the highest ampacity for strait DC, for AC strands might actually help a tiny bit (we are talking HF) based on stuff that user 't3slaco1l' discovered about stranded wires, but this is true for only something like a induction coil running in the ultrasonic + frequency. I believe changing the strand size might have a <5% effect.


But given that we are not getting solar power from a relativistic speed binary system of a star and a black hole and its steady sunlight, you would ideally want a single strand.


The rule is for everything conventional: if it weighs less in comparison without the insulation its simple fraud. you are getting skimmed on a commodity metal :'(


I recommend stripping insulation from some 2 meter segments, coiling them up, and weighing them, to see how much copper got skimmed.


Now there is also the question of the insulation. That is harder to test. But if they skimming copper wanna bet its something lower quality? Common test might be to burn it in a kiln at some temperature that leaves inorganic materials to measure percent of inorganic additive i.e. barium sulfate or sand that is pure filler. Common in plastics but its a  very specific proportion that you need. You can mess with the ratios to reduce cost and make it weaker etc.

SeanB:
Simplest test for the plastic is to take a 10cm strip of it, remove the copper, and use a lighter to try to ignite it. If it goes out within 30 seconds of removing the flame, or does not burn, unless you keep the flame on, it is the correct insulation with flame retardant, but if it carries on burning then cheap non flame retardant plastic was used.

Ian.M:
Stiff strands are suspicious from a conductor composition viewpoint.  See https://www.fscables.com/other/blog/CCA-CCS-CCC-vs-pure-copper-know-the-difference.html

* CCS is easy to spot - a magnet sticks to the core.
* CCA is a bit harder but the flame test easily detects it.
* CCC can only be detected by resistance and lack of ductility.

coppercone2:
oh yeah I forgot about CCC wire. better get your mohm meter

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