As an aside, how many people here can swear that they have seen a melted neutral conductor or connection due to additive hamonics?
A total of
ONE (for sure) in over 15 years... It was a maxed out panel feed with a
reduced neutral. Panel was scoped before and after the new feeder and panel to have high harmonic content, but still can only say it was a
contributing factor. The only other PQ problem sever enough for mention was a building that kept killing anything with a transformer... UPS's, E lighting inverters, and ballasts, etc. Loads of 4-wire circuits, but for more than a year on that project, no sign of a single burned neutral on the any new or existing wiring. New POCO transformer, and a seperate one, and service for the elevator (the main culprit) corrected the problem.
Harmonic issues do exist in varying degrees, but are rarely enough to cause issues great enough to think about change of wiring method. In just about all of the burned neutral wire-nut problems I have seen over the years, I can point more toward poor connection practices than anything else! Un-twisted wires in a cheap spring nut...
