I see control wires with power conductors quite often. 4-004(7)(a) excludes control wires from the derating calculations.
Some roof top units have ko's designed for entry through the return air. No need to go through the roof, at all.
There may be a derating factor for ambient if the feed runs across the roof. In Sask. its 50 Celsius, so I never bothered looking for it in the CEC.
crash, no thoughts besides that it is allowed. You have me curious, what are you thinking?
