Image credit: Daburn Electronics & Cable; Plantronics
Coiled cords and cables have a spring-like form that allows them to stretch and bend with minimal stress on the wire. They can be extended to a length several times greater than their at-rest length, but return to their original length when released.
Coil cords, as they are sometimes called, consist of straight sections followed by curly sections. To achieve their spring-like form, the curly sections of metal wire are wound around a mandrel. Typically, the wire’s geometry is round; however, rectangular or even oval cross-sections are sometimes used. After these coiled sections are wound, the cable is jacketed (typically a polymer) and then heat-set into that shape.
Coiled Cable Materials
Like other wire and cable products, coiled cables have a conducting material inside and an insulating or jacketing material outside. Coil cords may also be foil shielded, and use heat-laminated Mylar for heat shielding. Metals such as copper, aluminum, and tinned copper are used as conductors. Polyvinyl chloride (PVC) and polypropylene (PP) may be used to insulate and jacket the coiled cord. For resistance to mineral oils, cutting fluids, and abrasions, polyurethane (PU) jacketing is often used.
The GlobalSpec SpecSearch database contains different types of coiled cords and cables. These include retractile power cords and communication cords, as well as retractile test lead wires. Products may also be designated by application, with coiled cords and cables for automated equipment, generators, hand tools, soldering irons, portable appliances, and lighting.
Buyers of coiled cords and cables should consider retracted length, extended length, time to retract, and geometry when sourcing products. Typically, the extended length of a coil cable is 3 to 5 times greater than the retracted length. The time for a coiled cable to retract from its full working length may also be an important consideration, depending on the application. Cable geometry determines the retraction speed, with rectangular cross-sections retracting relatively quickly and round cross-sections retracting relatively slowly.
Additional product specifications include cable diameter, strands, working voltage, temperature rating, conductor color, and jacket color. Coiled cords and cables may be UL Listed and RoHS compliant, and meet other published guidelines for performance and safety.