The derating from heat is derived from Neher/McGrath calculations concerning heat loss factors(delta T) and formulae. It would not matter if the conduit was 24" in diameter, the delta T from the bundle would be the same. Additionally, as a current-carrying conductor with a typical Laminar flow cross-section, the additional generated magnetic fields(eddy currents from skining effects) further add to increase each conductors impedance...which generates more heat.
[This message has been edited by DiverDan (edited 03-17-2005).]
