Dịch vụ & Phân phốiCâu 23 / 521
Six 3 AWG THHN copper conductors (90 C ampacity 110 A) are in one raceway at 30 C ambient. After the fill adjustment, what is the derated ampacity?
a.110 A
b.77 A
c.88 A
d.100 A
Giải thích
With 4-6 current-carrying conductors the 80% adjustment applies: 110 A x 0.80 = 88 A. No temperature correction is needed at 30 C. 77 A wrongly uses 70%, and 110 A/100 A ignore the fill adjustment.
Trích dẫn luật: 2023 NEC §310.15(C)(1)Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- How many current-carrying conductors can be in a raceway before an adjustment (fill derating) factor must be applied?
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- A feeder supplies a continuous load of 176 A. What minimum conductor ampacity (before derating) is required?
- Using the 60 C column of Table 310.16, what is the ampacity of a 6 AWG copper conductor?
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- Which of the following is NOT a standard ampere rating for a fuse or inverse-time breaker per 240.6(A)?
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