We buy fire alarm cable.

The ratings and what they mean

Fire alarm cable carries a power-limited circuit and is rated by where it can run. FPL is the general rating, FPLR is for risers between floors, and FPLP is for plenum spaces where the jacket has to meet a stricter burn standard. The jacket is red and the print along it names the rating and the conductor count. The colour is a code requirement rather than a preference, and it is the fastest way to identify the family.

Conductor counts run from two to four in most installations, in 14, 16 and 18 AWG. Shielded versions appear where a circuit runs close to interference, and a drain wire appears with them. The conductor is usually stranded in the smaller sizes and solid in the larger ones, which is the reverse of what most people expect.

• FPL, general purpose
• FPLR, riser rated
• FPLP, plenum rated
• 2, 3 and 4 conductor
• 14, 16 and 18 AWG

Why the volume is small

A fire alarm device does not need much copper. A run to a horn strobe might be sixty feet of two conductor cable, and an entire floor of a building can use less cable than one feeder pull. That is the nature of the system, and it sets both the scale of the surplus and the size of the lot. That is also why a fire alarm lot is light to move and quick to sort.

The result is coils and part-used boxes rather than reels. A contractor finishing a renovation ends up with a shelf of opened 500 foot coils, a box of 1,000 foot cable opened for a single run, and a bundle of cut lengths that came out of the ceiling with the devices. All three are offered together. Boxes with the shrink still on are the easiest of the three to place.

Honest expectations on value

Fire alarm cable is not a high-value lot, and pretending otherwise wastes everybody's afternoon. The copper is thin, the jacket is a large share of the weight, and a coil of 18 AWG two conductor holds very little metal. What a lot is worth depends on whether the cable can be used again. A coil opened and closed twice is still a coil, and it is judged as one.

Where it has value is in reuse. A coil of FPLP still in its packaging is worth more as cable than as scrap, because plenum rated material is specified and not every contractor keeps it. A pile of cut lengths pulled from a ceiling is scrap, and it is reviewed as scrap. The two are graded apart so that neither is dragged down by the other.

Age matters more here than on most cable. The jacket on an old coil hardens, and the rating printed on it may belong to a code cycle that has since moved. Say how old the material is when you know, because age decides which of those two outcomes applies. An old coil with a superseded rating can still be used where the code allows, and that is a question for the installing contractor.

Sending a fire alarm lot

Give the rating, the conductor count, the AWG and the length on each coil. A photograph of the print on the jacket is worth more than a description, because it carries all four of those facts in one line. If the print has faded, say so and send a photograph of the cut end instead. Faded print is common on a coil that has ridden in a truck for a year, and it does not make the coil scrap.

Where the lot is a mixed shelf, photograph it as a group and count the coils by type. There is no need to separate anything before offering it. Sorting is part of the review, and twenty coils seen together are quicker to assess than twenty separate enquiries with twenty sets of photographs. A single photograph of the shelf, taken square on, is usually enough to start.

• Rating: FPL, FPLR or FPLP
• Conductor count and AWG
• Length on each coil or box
• Whether the box is sealed or opened
• Age, where the label shows a date code

Cable removed from a live system should be described as removed, not as surplus. The distinction changes how the lot is treated.