Mạch nhánh & Đi dâyCâu 144 / 521
Expansion fittings for rigid PVC conduit must be provided to compensate for thermal expansion and contraction where the length change is expected to be at least how much?
a.1/4 in
b.1/2 in
c.1 in
d.2 in
Giải thích
Section 352.44 requires expansion fittings where the length change of PVC due to temperature is expected to be 1/4 in or greater. PVC expands and contracts significantly with temperature. 1/2 in, 1 in, and 2 in are all beyond the 1/4-in threshold that triggers the fitting.
Trích dẫn luật: 2023 NEC §352.44Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- Rigid metal conduit (RMC) must be securely fastened within what distance of each outlet box, junction box, or termination?
- For 1/2-inch through 3/4-inch trade size rigid metal conduit (RMC), what is the maximum spacing between supports on a straight horizontal run per Table 344.30(B)?
- For 1/2-inch through 1-inch trade size rigid PVC conduit, what is the maximum support spacing per Table 352.30?
- Under Table 300.5, what is the minimum burial depth for a direct-buried rigid metal conduit (RMC) installed under a residential driveway of a one-family dwelling?
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- Where cables or raceways are run parallel to framing members, the wiring must be kept at least what distance from the nearest edge of a wood stud where nails or screws are likely, unless protected by a steel plate?
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