Dịch vụ & Phân phốiCâu 98 / 521
When a panelboard is used as service equipment, the main bonding jumper must be:
a.Installed to connect the grounded conductor to the panelboard enclosure
b.Omitted because the neutral is isolated
c.Installed only in a downstream sub-panel
d.Replaced by the equipment grounding conductor
Giải thích
At service equipment, 250.24(B) and 250.28 require a main bonding jumper connecting the grounded (neutral) conductor to the enclosure. In a downstream sub-panel the neutral is instead isolated, so the main bonding jumper belongs only at the service, never omitted or moved downstream.
Trích dẫn luật: 2023 NEC §250.24Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- A grounded (neutral) service conductor larger than 6 AWG is permitted to be identified by:
- Where a service has two to six service disconnects for a single service, they must be:
- The minimum depth of working space in front of a 208Y/120 V panelboard (0-150 V to ground, Condition 1: exposed live parts on one side, no live or grounded parts on the other) is:
- Where the grounding electrode conductor connects to a concrete-encased electrode, that portion of the conductor is not required to be larger than:
- Where the grounding electrode conductor connects to a made rod, pipe, or plate electrode, that portion of the conductor is not required to be larger than:
- For a feeder/service neutral, the portion of the maximum unbalanced load that exceeds 200 A may generally be calculated at:
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