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Appendix 4, section 6.1 equation 6

Former Community Member
Former Community Member

 

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Hi I am working through equation 6 for an ambient temperature of 50 degrees for 1mm 90degC thermoplastic cable (Table 4E2A)

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I get a correction factor of 0.95 for a 2A load. 

Do i divide the mV/A/m by this factor ? 

The text says multiply, but that would mean the resistance decreases with the increase in temperature (or have I got the sum wrong?)

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    Hm, the resistance figures in BS7671 are given for “circuit meters” so your number of 2X is rather suspect. It is the normal way to specify multicore electrical cables, although obviously not for singles used for other purposes! Another confusion. This temporary cable thing being discussed is also somewhat suspect too, at no point in BS7671 does it say much about “temporary” except in areas covered by section 711, and that is not what you are doing. It seems to me that a few have tried to take BS7909 and apply it to your situation which is not necessary. Just use BS7671.

    It will all be fine unless the sky falls in!

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  • 0

    Hm, the resistance figures in BS7671 are given for “circuit meters” so your number of 2X is rather suspect. It is the normal way to specify multicore electrical cables, although obviously not for singles used for other purposes! Another confusion. This temporary cable thing being discussed is also somewhat suspect too, at no point in BS7671 does it say much about “temporary” except in areas covered by section 711, and that is not what you are doing. It seems to me that a few have tried to take BS7909 and apply it to your situation which is not necessary. Just use BS7671.

    It will all be fine unless the sky falls in!

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