Dịch vụ & Phân phốiCâu 110 / 521
On a 4-wire delta system where the midpoint of one phase is grounded, the conductor with the higher voltage to ground (the high leg) must be durably and permanently marked, typically colored:
a.Orange
b.Blue
c.White
d.Green
Giải thích
Per 110.15, the phase conductor having the higher voltage to ground (about 208 V on a 120/240 V high-leg delta) must be marked by an outer finish that is orange or by other effective means at every point of connection. White identifies the grounded conductor and green identifies equipment grounding, so neither can mark the high leg.
Trích dẫn luật: 2023 NEC §110.15Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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