I certainly wouldn't have thought so.They can't do, can they?do the conductors of 2.5mm T+E 'clipped direct' really reach a temp of 70 °C with 27A flowing?
Indeed, and that's where these margins start causing confusion. At first sight, one could be excused for believing that "conductor operating temperature 70 °C" at the top of the CCC tables in the regs meant what it says, but it presumable doesn't. I guess it probably means that the temperature would rise to 70 °C if all of the margins ever 'got used up' by the prevailing situation, and that the temperature would get nowhere near that high at 27A. Hence, maybe they meant (and therefore should have written) "maximum permissible conductor operating temperature 70 °C". However, in that other discussion to which westie referred (the one about a 300A supply), people seemed to be talking as if the 70 °C (or 90 °C) temperatures would actually be seen with a current corresponding to the tabulated 'CCC'.The 27A would have to be the absolute maximum CCC but, as we have been discussing, a significant safety margin is built in.
Kind Regards, John