Flexible cables in stud walls

comparing ccc's of table 4F3A with RM E of 4D2A (if that's an appropriate comparison), see that apart from for 2.5mm2, the latter has more generous allowances than the former, so wasn't sure if RM B would be a suitable comparison, because if 4D2A is not as generous with flexes, that could put it below 20A.

The two tables are based on somewhat different assumptions - 4F3A is based I think on a 60 degree conductor temperature rather than 70 (probably more suitable for not feeling too hot if it's handled in service) and differing installation methods (flexes are more likely to be lying on a carpet rather than fixed to a wall), so there will be naturally be some variation. In your case where the flex is used much more like a fixed cable (and is suitable for running at 70 degrees), then 4D2A is likely to be a better approximation.

   - Andy.

comparing ccc's of table 4F3A with RM E of 4D2A (if that's an appropriate comparison), see that apart from for 2.5mm2, the latter has more generous allowances than the former, so wasn't sure if RM B would be a suitable comparison, because if 4D2A is not as generous with flexes, that could put it below 20A.

The two tables are based on somewhat different assumptions - 4F3A is based I think on a 60 degree conductor temperature rather than 70 (probably more suitable for not feeling too hot if it's handled in service) and differing installation methods (flexes are more likely to be lying on a carpet rather than fixed to a wall), so there will be naturally be some variation. In your case where the flex is used much more like a fixed cable (and is suitable for running at 70 degrees), then 4D2A is likely to be a better approximation.

   - Andy.

Thank you. I'm inclined to agree with you but my reservation (perhaps wrongly) is as my reply to mapj.