Dịch vụ & Phân phốiCâu 67 / 521
A service is supplied with 3/0 AWG copper service-entrance conductors. Using Table 250.66, the minimum size copper grounding electrode conductor is:
a.6 AWG
b.4 AWG
c.2 AWG
d.1/0 AWG
Giải thích
Table 250.66 requires a 4 AWG copper grounding electrode conductor for service conductors sized over 2/0 through 3/0 AWG copper. A 6 AWG is too small for this range, while 2 AWG and 1/0 AWG exceed what the table requires.
Trích dẫn luật: 2023 NEC §250.66Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- Overload protection for service-entrance conductors must be provided by an overcurrent device in series with:
- A feeder supplies a continuous load of 40 A and a noncontinuous load of 60 A. The minimum feeder conductor ampacity before applying any adjustment factors is:
- A feeder overcurrent device protecting a feeder that supplies continuous loads must have a rating not less than:
- At a grounded AC service, the grounded (neutral) conductor run to the service disconnecting means must be sized:
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- A feeder is protected by a 100 A overcurrent device. Using Table 250.122, the minimum size copper equipment grounding conductor is:
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