Mạch nhánh & Đi dâyCâu 172 / 521
Cables or raceways installed under metal-corrugated sheet roof decking must be kept at least what distance from the lowest surface of the roof decking to the top of the raceway or cable?
a.1-1/2 in
b.3/4 in
c.1 in
d.2 in
Giải thích
Section 300.4(E) requires cables and raceways under metal-corrugated sheet roof decking to be kept at least 1-1/2 in from the lowest surface of the decking, protecting the wiring from roofing screws. The smaller 3/4-in and 1-in distances are insufficient, and 2 in is more than the code minimum.
Trích dẫn luật: 2023 NEC §300.4(E)Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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