Thiết bị & Hệ thốngCâu 346 / 521
What distinguishes a non-power-limited fire alarm (NPLFA) circuit from a power-limited (PLFA) circuit?
a.Both are power-limited circuits
b.NPLFA circuits are always 24 V battery-supplied
c.PLFA circuits use Chapter 3 wiring methods only
d.NPLFA circuits are not power-limited and must use Chapter 3 wiring methods, while PLFA circuits are power-limited
Giải thích
An NPLFA circuit is supplied by a source exceeding the power-limited restrictions and therefore must be installed using Chapter 3 wiring methods with 600-volt-rated conductors. PLFA circuits use a power-limited source (100 VA maximum) and may use the lighter power-limited cabling of Article 760 Part III.
Trích dẫn luật: 2023 NEC §760.41Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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