SWA sub main

[jimmer]

I've been asked to carry out PIR on an idustrial unit on an old farm. The unit is supplied by a sub main and privatly metered. The sub main is a 35mm 4 core swa 3 phase and neutral on a 60947-2 100A MCCB i can see that the armouring on the cable is big enough to be the cpc but is this ok on a sub-main as this will be the main supply for the unit that i have been asked to do the PIR on?
I would always install a sub main with a seperate CPC or a 5 core SWA if i was installing it from new. By the way the main eathing is TNC-S.
Any help much appreciated

 

[Guest123]

Size wise the copper equivalent size of the steel armour is just over 37mm so even if the argument arose that the MEC should be the same size as the supply neutral conductor (35mm) it would still be sufficient. Even though upto 35mm a 16mm MEC would comply.


The only concern I would have is the earthing and bonding arrangements at the unit end of the system. But as you are carrying out a PIR it's down to you to check and see if they comply or not.