Mạch nhánh & Đi dâyCâu 184 / 521
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.1
b.0
c.3
d.2
Giải thích
Per 314.16(B)(4), each yoke or strap containing one or more devices counts as two volume allowances, based on the largest conductor connected to the device. Counting it as 1 or 0 understates the fill; a standard single device is not 3.
Trích dẫn luật: 2023 NEC §314.16(B)(4)Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- A 4" x 1-1/2" square box has a volume of 21.0 in³. With no clamps, devices, or other allowances, what is the maximum number of 14 AWG conductors permitted in the box?
- Using the same 21.0 in³ box with no other fill allowances, what is the maximum number of 12 AWG conductors permitted?
- Per Table 314.16(B), what is the free-space volume allowance required for a single 12 AWG conductor?
- 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 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?
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