Taking submain through loft of a house, I think it only needs to be rated at 60 amps, 80 amps would be nice. But ideally don't want to be fighting with 25mm swa cable, I have found out the hard way that it makes life very difficult, getting it through the house and also routing inside a fused switch.
At the moment thinking that buried in insulation a 16mm 3 core cable would probably have a capacity of about 60 amps. Looks like I will have to clip to batons screwed on to roof beams to keep the cable clear of insulation, still easier than fighting with 25mm cable.
A 16mm 70 deg C thermoplastic cable is rated at 57 amps with reference method 100. I have seen plenty of domestic consumer units supplied with 16mm twin and earth and never seen any heat issues.
Therefore thinking 16mm swa would be good enough, your thoughts.
