ECN Forum Forums General Topics of the Trade General Discussion Area Do All Electrical Engineers Understand the NEC?

Joe,
I don't understand why the NEC requires engineering supervision to apply this exception 4.It looks like a straight forward thing to do,parallel the neutral conductors for #2 or larger to relieve the heating effects of the neutral due to harmonic currents.
It would require testing,IMO, after the new conductor(s)is placed in parallel to see if the desired effect(lowering of temp and voltage drop) is achived.Maybe that is what the NEC is getting at????
Chris