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London Consumer Unit Fires.

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It is comforting to know that there are apparently no consumer unit fire these days in London (or elsewhere) since all of the plastic consumer units have been replaced by metal enclosure types.


But, do not forget that there might be lots of sub-standard cable cooking and smouldering in people's homes installed years ago.


Lest we forget.........

https://www.bbc.co.uk/news/uk-41391343


Z.
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    Simon Barker:

    You could measure the diameter of the cable using vernier callipers.  From that calculate the cross-sectional area, and see if it's what it is supposed to be.




    That doesn't work. The size of the cable is the "nominal cross-sectional area" which is not necessarily the same as the actual csa. The purer the copper, the less csa is needed, but then that gives rise to other problems (e.g. work hardening from bending). The good manufacturers will have the copper core at an optimum and make the cable from as little copper as the standard will allow and hence maximise profits, which are little enough for cable makers anyway.

    Take a look at IEC 60228 and you will see that the measure of the nominal diameter is the resistance, not how much copper is in the cable.

    Alasdair

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  • 0

    Simon Barker:

    You could measure the diameter of the cable using vernier callipers.  From that calculate the cross-sectional area, and see if it's what it is supposed to be.




    That doesn't work. The size of the cable is the "nominal cross-sectional area" which is not necessarily the same as the actual csa. The purer the copper, the less csa is needed, but then that gives rise to other problems (e.g. work hardening from bending). The good manufacturers will have the copper core at an optimum and make the cable from as little copper as the standard will allow and hence maximise profits, which are little enough for cable makers anyway.

    Take a look at IEC 60228 and you will see that the measure of the nominal diameter is the resistance, not how much copper is in the cable.

    Alasdair

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