I think it's probably just habit.And the earth should be thicker in conduit. Or maybe that is just habit
In a literal sense, you are correct, although I think that "ignore" is a fairly hash word to use in relation to the result of an intelligent risk assessment (which one might call 'electrical common sense'). Don't forget that the legal requirement is to comply with Part P of the Building Regs, which does not necessarily require compliance with the letter of BS7671.Yes, in that you seem to support the ignoring or the wiring Regs, based upon a purely personal view of risk assessment
That's true, but only because of 434.5.2 (which we rarely hear people mentioning).If the CPC is the same size as the live conductors, it isn't necessary to work out if it is big enough.
Maybe, but it seems that people do not even do enough (and/or are not capable of doing enough) thinking to realise that 'working out' (calculation) is not necessary.Yes, because then it isn't necessary to work out if it is big enough.
...and 4mm².From T+E, we know (without questioning it) that, for example, a 1.5mm² CPC is regarded as adequate in relation to a circuit for which 2.5mm² live conductors are appropriate -
Yes - and 4mm² - I suppose it is adequate in all circumstances, is it?so, without doing any 'working out', anyone capable of thought should realise that a 1.5mm² 'single CPC' would be adequate for a circuit whose live conductors were 2.5mm² singles.
Yep, that too....and 4mm².
Are you asking whether a 1.5mm² CPC is always adequate for a circuit whose live conductors were 2.5mm² (or 4mm²)?Yes - and 4mm² - I suppose it is adequate in all circumstances, is it? Would you know without working it out?
That's easy, but you're perhaps asking the question the wrong way around. The point is that, in adiabatic terms, the live conductors are 'oversized' - but, for those live conductors, there is also the consideration of the ('continuous') current-carrying-capacity (the antithesis of 'adiabatic'). In other words, considering 2.5/1.5mm² T+E, 1.5mm² would be adiabatically adequate for the live conductors, but the cable would then only have the CCC of 1.5mm² cable, not that of "2.5mm²" cable.Perhaps the wrong questions are being asked. Why does T&E have smaller CPCs?
You mean flex? If so, that's another 'good question' - since theory would indicate that the same 'conventional relationship' between CPC and live conductor CSAs would be just the same as in T+E.Why does 3 core (and more) not have smaller CPCs?
Indeed - but I didn't even dare mention that one ....Well for when the cpc gets used for something else
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