Services & DistributionCâu 54 / 110
A metal underground water pipe qualifies as a grounding electrode if it is in direct contact with earth for at least how many feet?
a.10 ft
b.5 ft
c.3 ft
d.1 ft
Giải thích
A metal underground water pipe electrode must have at least 10 ft of contact with earth (bonding connection made within 5 ft of entry).
Trích dẫn luật: 2023 NEC 250.52(A)(1)Luyện miễn phí toàn bộ 110 câu hỏi — không cần đăng ký.
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