If you have branch circuits of nonlinear loads and there is one neutral conductor to one phase conductor, does the neutral conductor count per 310.15.(B)(2)? KGD
Non linear loads would not have any affect on two wire circuits.
Both the Grounded and Ungrounded conductors would be current carrying conductors and would have to counted as far as Table 310.15(B)(2) is concerned. In other words, after you installed more than one circuit in a conduit you would have to start adjustments.