I have been out and about doing my 2346 experienced worker assessments and touched base with some relatively large PV roof installations. Peaked my interest in these systems greatly! I was about to ask about the use of SWA multicore on the DC side when I was directed to GK’s excellent video presentation on the introduction of the current COP which looked like it was given at an IET presentation at some electrical event. The caution about using SWA cables seemed to perplex a couple of guys at the front. Perhaps they were diligent installers who had noted the acknowledgment about SWA being a suitable wiring system in the previous COP.

My take from what GK said and what is says in 7671 is that SWA is not a suitable wiring system for the DC side of PV systems. I have noted that in the several systems I have visited, all of which are no more than a few months old, almost exclusive use of SWA on the roof.

One installation underway at the moment has almost 1Mwp on the roof of a large warehouse. Multicore swa runs from the combiner boxes on the roof to the optimisers are up to 200m in places. Everything very neatly installed. Do you think this is just a technical breach of 7671 or is there a clear worry about insulation breakdown, perhaps as a result of water ingress into the jacket? After all, SWA is often used in the most arduous conditions outdoors.