18/2 Plenum Security Alarm Cable - CMP/CL3P Rated, 7 Strand Copper, 1000ft White

This is the two-conductor plenum cable for the power runs of a security or low-voltage system: two 18 AWG stranded bare copper conductors, black and red, under a white low-smoke PVC jacket that carries the plenum listings. It's rated CL3P under NEC Article 725 for Class 3 power-limited circuits (and by the code's substitution rules for Class 2 as well), CMP under Article 800 for communications, and FPLP under Article 760 for power-limited fire alarm circuits, so the one cable can feed a door strike, a siren, a speaker, a power supply, or a 12 V or 24 V accessory, and run through a return-air plenum, a drop ceiling, or a raised floor without conduit. 18 AWG is the gauge for anything that draws real current, with about half the loop resistance of 22 AWG, and the 7-strand conductors bend around a ceiling and land in a terminal block more easily than solid wire.

It's unshielded, which is the right construction for power, strike, and speaker runs where there's no data signal to protect, and it keeps the cable slim and the price down. The cable is ETL Listed, RoHS compliant, and made in the USA, and it comes in a 1000 ft pull box with sequential footage marks on the jacket.

Features

• Plenum rated three ways. CL3P under NEC Article 725, CMP under Article 800, and FPLP under Article 760, so it's listed for return-air plenums, drop ceilings, and raised floors on security, control, communications, and fire alarm circuits alike, and the CL3P listing covers Class 2 circuits under the code's substitution rules.
• Two 18 AWG stranded bare copper conductors. About half the loop resistance of 22 AWG, for strike, siren, and power-supply runs, on 7-strand conductors that bend around a ceiling and seat in a terminal block without fighting.
• Black and red. The standard pair coding for polarity on a DC power or alarm circuit.
• Unshielded. The right construction for power, strike, and speaker circuits, and the easier one to terminate.
• Low-smoke PVC insulation and jacket. A 0.009 in insulation wall on each conductor and a 0.018 in jacket, both the low-smoke compounds a plenum listing requires.
• White jacket. Reads as general-purpose low-voltage in a ceiling or a tray, and stays distinct from red fire alarm and blue data cable.
• 300 V, 75 °C. The ratings a Class 2, Class 3, or power-limited fire alarm circuit calls for.
• 3.99 mm outer diameter. Slim enough to bundle by the dozen and fish through a tight ceiling.
• ETL Listed, RoHS compliant, made in the USA.
• 1000 ft pull box. Sequential footage marks on the jacket; pays out from the box without a spool stand, and the box stacks in a van.

Where It Fits

It suits electric strikes and maglocks on access control doors, sirens, strobes, and sounders on an alarm output, 12 V and 24 V power from a supply to keypads, readers, and auxiliary devices, 70 V and 8 Ω paging and background music speakers in a ceiling, thermostat and damper control pairs, power-limited fire alarm circuits that call for a stranded pair, and any two-conductor low-voltage run through a plenum ceiling in an office, school, hospital, hotel, or store.

Good to Know

Run the voltage-drop calculation on any pair that carries power. An 18 AWG pair is about 13 ohms per 1000 ft round trip, so a 12 V strike drawing 0.5 A at the far end of a 200 ft run loses about 1.3 V, and a 24 V siren drawing 1 A at 300 ft loses about 3.9 V; for a heavier load or a longer run, step up to 16 AWG or move the power supply closer. Speaker runs are figured on impedance and wattage rather than current, and 18 AWG is comfortable for 70 V distributed systems over several hundred feet. A maglock is a continuous load, so size the run for its holding current and the supply's low-battery voltage, not just nominal. Keep the circuits in their classes: Class 2 and Class 3 circuits can use this cable, but a Class 1 circuit can't, and the NEC requires power-limited wiring to stay separated from power conductors in raceways and boxes. Stranded conductors want a ferrule or a proper fold-back before they go under a screw terminal; a stray strand is the short that takes a zone into trouble. Plenum-rated cable is for the air-handling space, not for inside the ductwork itself. If the ceiling isn't a plenum, a riser or general-purpose cable does the same job for less. The jacket isn't UV stabilized or rated for wet locations or burial, so an outdoor siren or contact should be fed through conduit or from a cable rated for it.

Specifications

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