Electrical. do you derate elec conductors ran in parallel.eg what size parallel conductors for 400 amp service

Question

What size electrical conductors run in parallel do you need to feed a 400 amp service

Answer 1

There are different sizes depending on how many sets, conduits, etc, plus I won't do your homework for you. But, yes, each wire in a conduit is counted for derating. You don't even say what kind of service, so using 3 phase 3 wire as an example, if you put the whole thing in one conduit and 2 wires per phase would be 6 current carrying wires in a conduit, and would need to be derated. If you split it into 2 conduits, each having 3 (one from each phase), then you wouldn't derate. Because of this I believe multiple conduits are common for parallel installations.