Wiring Methods & MaterialsCâu 63 / 120
A short raceway nipple no longer than 24 inches connects two enclosures. What fill percentage is permitted?
a.31 percent
b.40 percent
c.53 percent
d.60 percent
Giải thích
Notes to Chapter 9, Table 1 permit a nipple not exceeding 24 inches in length to be filled to 60 percent of its total cross-sectional area, because heat buildup and pulling friction are both minimal over such a short run. The 40, 53 and 31 percent values are the normal fills for three or more, one, and two conductors respectively.
Trích dẫn luật: 2023 NEC Chapter 9, Table 1, Note 4Luyện miễn phí toàn bộ 120 câu hỏi — không cần đăng ký.
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