Derating

[fisherelectric]

I have a situation I'm not too familiar with where I'm installing circuits to an attic in PVC to take the load from 54 solar panels. These panels put out ~195 watts at 230 volts on a good day. The solar contractor wants 5 230 volt circuits on 2 pole 15a breakers. That would be 10 conductors in the conduit, then romex through the attic to each splice point for the wires coming from the arrays. Do I need to derate for the number of wires in the conduit per 310.15(B)(2)(a), 50%, plus ambient temp in attic (~125 F) for the romex, plus continuous duty for the whole circuit? '05 code
Each panel has a micro-inverter and are interconnected thru a wiring harness so all I'm contracted to do is run the circuits and hook-up the leads from the harnesses.