FPLP vs. FPLR: How to Choose the Right Fire Alarm Cable Rating

Pull the wrong fire alarm cable and the inspector won’t care how clean your terminations look. FPLP vs. FPLR is one of the most common questions on a commercial fire alarm job, and it comes down to one question: what space is the cable passing through? Both are power-limited fire alarm (PLFA) cables recognized by the National Electrical Code (NFPA 70). The difference is the fire test each one passes, and that test decides where each one can legally run.

Below, we break down what each rating means, how the substitution rule works, how to choose between 18/2 and 14/2, and why reel-in-box packaging saves time on the pull.

What FPLP Cable Is Rated For

FPLP stands for Fire Power-Limited Plenum. To earn the rating, a cable must pass the NFPA 262 flame test, which measures both flame spread and smoke generation. It’s the most demanding test in the PLFA family, and it’s why FPLP is the only PLFA cable type you can run exposed through a plenum.

The reasoning is straightforward. A plenum is part of the building’s air distribution system. If a cable jacket burns there, the HVAC system can carry smoke to every space it serves. FPLP jackets are formulated to limit both the flame and the smoke.

Where you’ll use FPLP cable: above drop ceilings used as return-air plenums, under raised floors used for air handling, and anywhere the mechanical drawings show the cavity is part of the air path. If you’re not sure whether a ceiling is a plenum, check the HVAC drawings. If air moves through it, treat it as one.

What FPLR Cable Is Rated For

FPLR stands for Fire Power-Limited Riser. It’s tested to UL 1666, a vertical-shaft test that uses a substantial fire source to see whether a cable will carry flame to the floor above. Riser cable is built to keep fire from climbing the building along the cable itself.

Where you’ll use FPLR cable: vertical runs in shafts, floor-to-floor penetrations, and the backbone runs that carry circuits from the fire alarm control panel up to each floor in a multi-story building. On multi-dwelling unit projects, that same riser shaft may also carry the building’s fiber backbone. The Fiber Broadband Association’s white paper on making a building fiber-ready lays out how that backbone is typically structured, which helps when you’re coordinating space in a shared shaft.

What FPLR can’t do: it can’t run exposed through a plenum. Some installations allow lower-rated cable inside certain metal raceways, but that’s a conversation with your authority having jurisdiction (AHJ), not a default.

FPLP vs. FPLR Side-by-Side

Here’s a detail that simplifies planning. On our unshielded 18/2 and 14/2 lines, the plenum and riser versions share the same solid bare copper conductors, PVC insulation, 300 V RMS rating, -20°C to +75°C operating range, and nominal outside diameter: 0.15 in. for 18/2 and 0.20 in. for 14/2. The jacket compound and listing are what change. Your conduit fill and support planning stay the same when you switch ratings. Only the pathway decides.

FPLP vs. FPLR and the Substitution Rule

The NEC lets a higher-rated cable substitute for a lower-rated one, never the reverse. For power-limited fire alarm cable, the hierarchy runs FPLP → FPLR → FPL. FPLP can go anywhere. FPLR can replace FPL in general-purpose runs. FPL stays on a single floor, outside plenums and risers.

Read the jacket print, not the color. The rating is printed along the cable. On our fire alarm cable, you’ll find the TYPE FPLP or TYPE FPLR designation, the ETL mark, and sequential footage markers every few feet.

Many contractors standardize on FPLP for an entire building. One cable covers every pathway, a riser reel never ends up in a plenum by mistake, and the truck stock is simpler. The tradeoff is cost, so on riser-heavy jobs with limited plenum runs, splitting the order still makes sense. If you’re involved on the design side, ANSI/BICSI 007 is the BICSI standard that now covers electronic safety and security systems within a building’s broader ICT infrastructure. It’s a good reference for planning life-safety pathways alongside everything else in the ceiling.

18/2 or 14/2? Matching Gauge to the Circuit

The rating tells you where the cable can go. The gauge tells you how far the circuit can reach. Both lines come in 18 AWG and 14 AWG 2-conductor versions, and the resistance difference is significant:

18 AWG is the usual choice for lower-current circuits such as initiating device circuits and addressable signaling line circuits. 14 AWG is more common on notification appliance circuits, where horns and strobes draw more current and voltage drop over long runs becomes the limiting factor. Either way, size the circuit to the panel manufacturer’s wiring guidelines and a voltage drop calculation, and follow NFPA 72 for system requirements.

Why Reel-in-Box Packaging Matters on the Jobsite

All four SKUs below ship as 1,000 ft. of red cable in a reel-in-box. The reel sits inside the carton and pays out through the box, so you don’t need to haul a spool or set up a ladder, and the cable feeds without backlashing or kinking. The carton also protects the cable in the truck and on the floor, and the sequential footage print shows how much you have left before you start a long run.

FPLP (PLENUM)			FPLR (RISER)
216-182/P/RB/RD	216-142/P/RB/RD		216-182/R/RB/RD	216-142/R/RB/RD
SIZE: 18/2	SIZE: 14/2		SIZE: 18/2	SIZE: 14/2
– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – | PACKAGE: 1,000 ft. Reel-in-Box | – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –
WEIGHT: 20 lb. (9.07 kg)	WEIGHT: 38 lb. (17.24 kg)		WEIGHT: 20 lb. (9.07 kg)	WEIGHT: 38 lb. (17.24 kg)

Each of these is ETL listed, RoHS compliant, and built with a low-smoke PVC jacket and a polyester rip cord for fast stripping. They suit smoke detectors, pull stations, addressable fire alarm systems, and burglar alarm circuits. If you need other colors, the same cables are available on 1,000 ft. wooden spools. Reel-in-box packaging is red only.

Frequently Asked Questions