We buy control cable.

Numbered conductors and why the count comes first

Control cable is multi-conductor 600 V cable built for control circuits rather than power. The conductors are typically 14, 12 or 10 AWG, and they are identified either by printed numbers running the length of each conductor or by a colour code, sometimes both. Constructions run from two conductors up to thirty-seven.

The conductor count leads the review because it sets almost everything else: how the cable is terminated, how it is pulled through a conduit, and how much of it a plant can actually use. A 2-conductor control cable and a 37-conductor cable are not interchangeable, and a lot of one does not help someone who needs the other.

Numbering is the other half. Printed numbers survive a pull and a re-termination, which is why plants specify them for anything that will be worked on more than once. Colour-only constructions are common too, but they lose their identity the moment a spliced end is cut back. A plant that asks for numbered conductor usually asks for the shield as well.

• Two to thirty-seven conductors in one jacket
• 14 AWG for signal and interlock circuits, 12 and 10 for heavier control
• Numbered, colour-coded or both
• Overall shield with a drain wire on analogue and long runs
• Tray-rated and conduit-rated jackets, some with sunlight resistance

Panel and MCC replacements leave the most behind

Most control cable surplus starts with a panel change. The electricians order reels for the worst case, pull what the new drawings call for, and hand back what is left on the reel plus the offcuts from every home run. A rebuild of one MCC lineup can produce a dozen short lengths in four different conductor counts.

Skid and package work adds another stream. Equipment arrives pre-wired, gets modified on site, and the original cable is pulled out and replaced with something longer, shorter or shielded. The removed cable is often still coiled and still numbered, which makes it the easiest material in the plant to identify.

Instrument and electrical crews hold the rest. A maintenance crib keeps control cable for repairs, buys a reel when it runs low and never quite uses one up. Those reels sit on a shelf for years, and they are usually the cleanest items in a surplus lot because they never went outdoors.

A partial reel with the original tag still attached is the best version of this lot. Photograph the tag before the reel moves.

Shielded, unshielded and the drain wire

Shielding changes both what the cable is for and how it is graded. An overall foil shield with a drain wire protects low-level signals from electrical noise in a plant full of drives and contactors. Braid shields do the same job with better mechanical strength and a higher flex life.

A shielded lot is reviewed on whether the shield is continuous and whether the drain wire is intact at the ends. Cable that was cut out of service with the shield cut back hard loses a little length but keeps its construction. Cable that was pulled through a conduit with the foil torn open is a different matter, and the damage usually shows at the end.

Unshielded control cable is the plain case and the larger volume by far. It is judged on conductor count, gauge, jacket condition and length. There is no shield to inspect, so the cut end and the print tell nearly the whole story. Send a photograph of the print and a count of the conductors, and little else is needed to place it.

Sorting a control lot before it is collected

Control cable is easy to sort badly. The reels look alike from the outside, and the differences that matter are printed on the jacket or buried in the conductor count. Sorting by count and gauge into separate groups takes a few minutes and turns a mixed pile into a list a buyer can work from. Three piles of the same count take half the time to review.

Send the conductor count, the gauge, the shielding if any, the approximate length on each reel and the approximate length of each cut piece. For a crate of offcuts, a count by size and a rough average length is enough to start. Nobody needs each piece measured individually. Two or three representative pieces in a photograph say more than a complete list of lengths.

Loading is straightforward. Control reels are light enough to move by hand or with a pallet jack, and a crate of offcuts goes onto a liftgate. Say where the material is stored and whether it is still racked inside a panel area, since a rack full of cable takes longer to clear than a pallet on the floor.

• Conductor count and gauge on each reel
• Shielded or unshielded, with the drain wire intact
• Length on the reel, and length of each offcut
• Jacket condition, and whether the reel has been outdoors