Mạch nhánh & Đi dâyCâu 205 / 521
In a 4-wire, 3-phase wye circuit supplying nonlinear (harmonic-producing) loads, how is the neutral treated for conductor-count adjustment?
a.It is counted as a current-carrying conductor
b.It is never counted
c.It is counted as one-half
d.It counts only if it is bare
Giải thích
Per 310.15(E), where the major portion of the load is nonlinear, harmonic currents load the neutral, so it must be counted as a current-carrying conductor. This differs from a balanced wye neutral, which normally is not counted.
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 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 3-wire, single-phase circuit (two hots and a neutral), how is the neutral treated when counting current-carrying conductors for 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?
- Six current-carrying 10 AWG THHN copper conductors (40 A at 90°C) run in a raceway at 40°C ambient. Applying the 0.91 ambient correction and the 0.80 conductor-count adjustment, what is the resulting ampacity?
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