Kiểm tra & Khắc phục sự cốCâu 494 / 521
A terminal on a device is marked 'CU' only. What does this mean for terminations?
a.It may be used with copper or aluminum interchangeably
b.It is listed for copper conductors only; aluminum must not be landed on it
c.It requires antioxidant paste with any conductor
d.It is rated for control wiring only
Giải thích
A 'CU'-only marking means the terminal is tested and listed for copper conductors exclusively; landing aluminum can cause overheating and failure from oxidation and dissimilar-metal effects. Only terminals marked 'CU-AL' or 'AL-CU' accept aluminum. The marking is about conductor material, not paste (c) or a voltage/control limit (d).
Trích dẫn luật: 2023 NEC §110.14Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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