Dịch vụ & Phân phốiCâu 108 / 521
A separately derived system (such as the secondary of a transformer feeding a distribution panel) must have a system bonding jumper connecting:
a.The two ungrounded phases together
b.The grounded conductor to the supply-side bonding jumper and equipment grounding conductor at the source or first disconnect
c.The neutral to a branch-circuit breaker
d.Only the metal raceway to earth
Giải thích
Per 250.30(A), a separately derived system requires a system bonding jumper connecting the grounded conductor to the supply-side bonding jumper and/or equipment grounding conductor at a single point (at the source or the first disconnect). Bonding phases together or omitting the grounded conductor connection would not establish the required fault path.
Trích dẫn luật: 2023 NEC §250.30Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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