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Thursday, July 14, 2022
Question:
Good Afternoon Code Friends.
In a 3-Phase 4-Wire panelboard feeder (over 24 inches), does the neutral count as a current-carrying conductor? And if so does the ampacity need to be adjusted according to the table "Adjustment Factors for More Than Three Current-Carrying Conductors" in Section 310?
Curtis Syswerda
A
Answer:
Hi Curtis,
The neutral of a 3-phase, 4-wire feeder counts as a current-carrying conductor if it aligns with the criteria in Section 310.15(E)(3) [2020 NEC]. Otherwise, only three current-carrying conductors are present and the adjustment factors in 310.15(C)(1) would not have to be applied.