2026-08-27
When specifying a fire alarm system for a high-rise office tower, one question must be answered before any cable is ordered: which cable belongs in the plenum, and which in the riser? The answer determines code compliance, circuit power, and system behavior under smoke and heat.
The red jacket is the most visible feature, but the markings matter. FPL, FPLR, and FPLP are classifications defined by the U.S. National Electrical Code (NEC), not brand names:
1. FPL general-purpose: ordinary fire alarm wiring;
2. FPLR riser-rated: for vertical risers, preventing fire from spreading floor to floor;
3. FPLP plenum-rated: for air-handling spaces, with the strictest smoke and flame requirements.
Critical circuits may use fire-survivability cables such as MC armored or MI mineral-insulated cable to maintain circuit integrity during a fire. In modern life-safety systems, coaxial cable is often used for alarm-verification video monitoring, while fiber optics interconnect networked systems.
Fire alarm cable selection is life-safety critical — always consult professional manufacturers for design and specification.