Dịch vụ & Phân phốiCâu 92 / 521
A feeder is the main power feeder to a single dwelling and carries the entire load. What allowance does the dwelling feeder provision give for sizing this conductor?
a.It must be sized at 150% of the service rating
b.It may be sized at 83% of the service rating using the dwelling conductor provisions
c.It must always match the utility transformer
d.It cannot be smaller than 250 kcmil
Giải thích
Section 310.12(B) permits the main feeder to an individual dwelling (that carries the total load) to be sized using the reduced dwelling-service-conductor values, effectively 83% of the service rating. The other options misstate or invent sizing rules not found in the code.
Trích dẫn luật: 2023 NEC §310.12Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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