Services, Grounding & BondingCâu 57 / 120
On the load side of the service disconnecting means, what is the general rule for using the grounded neutral conductor to ground equipment enclosures?
a.It is permitted only in dwelling units
b.It is permitted if the neutral is at least 6 AWG copper
c.It is permitted in any panelboard fed from the service
d.It is not permitted; a separate equipment grounding conductor must be used
Giải thích
Downstream of the service disconnect the neutral and the equipment grounding conductor must be kept separate so that normal load current does not travel on enclosures and raceways. Bonding them together at a subpanel creates parallel neutral paths and objectionable current, and neither conductor size nor occupancy type changes this general prohibition.
Trích dẫn luật: 2023 NEC §250.142(B)Luyện miễn phí toàn bộ 120 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- What is the minimum service disconnecting means rating for a one-family dwelling?
- What is the minimum clearance above a residential driveway for overhead service conductors limited to 150 volts to ground?
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- Ground-fault protection of equipment is required for a solidly grounded wye service with more than 150 volts to ground when the disconnect is rated at least what value?
- How must a panelboard be protected against overcurrent?
- A dry-type transformer rated 112.5 kVA or less is installed indoors. What is the minimum separation from combustible material unless it is separated by a fire-resistant heat-insulating barrier?
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