Mạch nhánh & Đi dâyCâu 187 / 521
A box contains five 12 AWG current-carrying conductors, one 12 AWG equipment grounding conductor, one internal cable clamp, and one switch on a yoke (all conductors 12 AWG). What total box volume is required?
a.18.00 in³
b.15.75 in³
c.20.25 in³
d.22.50 in³
Giải thích
At 2.25 in³ each: five conductors = 11.25, EGCs (as one) = 2.25, clamp (as one) = 2.25, and the yoke = 2 × 2.25 = 4.50. Total = 11.25 + 2.25 + 2.25 + 4.50 = 20.25 in³. The other values omit one or more required allowances.
Trích dẫn luật: 2023 NEC §314.16(B)Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- In a box-fill calculation, a single device (a receptacle or switch mounted on a yoke or strap) counts as how many conductor volume allowances?
- A box contains three internal cable clamps. In the box-fill calculation, how many volume allowances do the clamps require in total?
- A box has four 12 AWG equipment grounding conductors entering it. How are they counted in the box-fill calculation?
- A single unbroken conductor passes straight through a box without being spliced or terminated. For box fill, it is counted as how many conductors?
- How are conductors that both originate and terminate within the box (such as short pigtails or jumpers) treated in a box-fill calculation?
- Per Chapter 9, Table 1, what is the maximum permitted conduit fill percentage when three or more conductors are installed in a raceway?
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