Mạch nhánh & Đi dâyCâu 239 / 521
Per 210.5(C), where a building is supplied by more than one nominal voltage system, how must the ungrounded branch-circuit conductors be treated?
a.All must be black
b.All systems may share the same color
c.Each system's ungrounded conductors must be identified (e.g., by color), with the means posted at each panelboard
d.They may be left unmarked
Giải thích
Section 210.5(C) requires ungrounded conductors of each system to be identified by phase or line and system, with the identification method documented and readily available (posted) at each branch-circuit panelboard. Leaving them unmarked or using one color for all systems defeats the safety intent.
Trích dẫn luật: 2023 NEC §210.5(C)Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- If the one-way length of a circuit run is doubled while current and conductor size stay the same, what happens to the voltage drop?
- Per 200.6(A), a grounded (neutral) conductor 6 AWG or smaller must be identified by which of the following?
- Per 250.119, an equipment grounding conductor may be identified by which of the following?
- Per 110.15, on a 4-wire delta-connected 120/240 V system, the high-leg (the conductor with the higher voltage to ground) must be identified by what color?
- Which set of colors is NOT permitted for ungrounded (hot) conductors, because these colors are reserved for other uses?
- Per 200.6(B), how may a grounded (neutral) conductor larger than 6 AWG be identified?
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