Feeder/Service Neutral Demand Load (NEC 220.61)
Sizes the feeder/service neutral under NEC 220.61: it carries the maximum unbalanced load, but the portion over 200 A may be taken at 70% (a 250 A unbalanced load -> 200 + 0.70x50 = 235 A). 220.61(C) prohibits the reduction for nonlinear-load portions (electric-discharge lighting, electronic loads), which stay at 100%. A sizing demand, not an operating current; the AHJ and the load classification govern.
Formula and source
ordinary: neutral = min(load, 200) + 0.70 x max(load - 200, 0); nonlinear (220.61(C)): neutral = full unbalanced load (no reduction). The first 200 A of unbalanced load at 100%, the portion over 200 A at 70%.
Feeder and service neutral load, NEC 2023 220.61(B) (70% on the part over 200 A) and 220.61(C) (nonlinear-load prohibition), by name.
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