Mạch nhánh & Đi dâyCâu 204 / 521
In a 3-wire, single-phase circuit (two hots and a neutral), how is the neutral treated when counting current-carrying conductors for adjustment?
a.Always counted as current-carrying
b.Counted only if it is 12 AWG
c.Counted as one-half a conductor
d.Not counted, since it carries only unbalanced current
Giải thích
Per 310.15(E), the neutral of a 3-wire single-phase circuit carries only the unbalanced current and is not counted as a current-carrying conductor. It would be counted only in a 4-wire wye supplying significant nonlinear (harmonic) load.
Trích dẫn luật: 2023 NEC §310.15(E)Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- Per Table 310.15(C)(1), what adjustment (derating) factor applies when there are 7 to 9 current-carrying conductors in a raceway?
- Per Table 310.15(C)(1), what adjustment factor applies when there are 4 to 6 current-carrying conductors in a raceway?
- Per Table 310.15(C)(1), what adjustment factor applies when there are 10 to 20 current-carrying conductors in a raceway?
- In a 4-wire, 3-phase wye circuit supplying nonlinear (harmonic-producing) loads, how is the neutral treated for conductor-count adjustment?
- Is an equipment grounding conductor (EGC) ever counted as a current-carrying conductor when applying conductor-count adjustment factors?
- An 8 AWG THHN copper conductor (55 A at the 90°C column) is installed where the ambient temperature is 46–50°C. Using the 90°C correction factor of 0.82, what is the corrected ampacity?
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