Mạch nhánh & Đi dâyCâu 176 / 521
Under 240.4(D), what is the maximum overcurrent protection permitted for a 12 AWG copper branch-circuit conductor, absent a specific exception?
a.20 A
b.25 A
c.30 A
d.40 A
Giải thích
Section 240.4(D)(5) limits 12 AWG copper conductors to a maximum overcurrent device of 20 A, which is why 12 AWG is standard for 20-A branch circuits. 25, 30, and 40 A all exceed the small-conductor protection limit for 12 AWG copper.
Trích dẫn luật: 2023 NEC §240.4(D)Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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