Dịch vụ & Phân phốiCâu 76 / 521
A feeder has a maximum unbalanced (neutral) load of 250 A. Applying the neutral demand provisions, the minimum neutral conductor ampacity is:
a.175 A
b.200 A
c.250 A
d.235 A
Giải thích
Per 220.61(B), the first 200 A of unbalanced load is at 100% and the portion above 200 A may be taken at 70%: 200 + (50 x 0.70) = 235 A. Sizing at the full 250 A ignores the permitted demand, and 175 A/200 A understate the required capacity.
Trích dẫn luật: 2023 NEC §220.61Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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