Dịch vụ & Phân phốiCâu 75 / 521
When conductors are installed in parallel, the paralleled conductors of each phase, neutral, or grounded circuit conductor must:
a.Be different lengths to balance impedance
b.Be the same length, same conductor material, same size, and have the same insulation type and termination
c.Use different sizes in each raceway
d.Only match in the ungrounded conductors
Giải thích
Per 310.10(G)(1), all parallel conductors of the same circuit designation must be the same length, material, cross-sectional area (size), and insulation, and terminate the same way, so current divides evenly. Different lengths or sizes cause unequal current sharing and overheating.
Trích dẫn luật: 2023 NEC §310.10(G)Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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