The cables are self-regulating and come with T-ratings of T2C, T3, T4A, T5 and T6, corresponding to maximum sheath temperatures in the range of 446°F to 185°F. They are available in a wide range of wattage and voltage ratings, from 3 W/Ft at 120 VAC up to 20 W/Ft at 277 VAC. Circuit lengths up to 780 ft. are possible.
The cables utilize a special semiconductive polymer core matrix bonded to the conductors, which provides self-regulation and makes an over-temperature condition all but impossible. Because the core's electrical resistance varies inversely with temperature, the cables are power efficient, consuming less energy when lower heat is required. A flame-retardant fluoropolymer inner jacket insulates the core and heat trace wires from a tinned copper braid that provides mechanical support and a positive ground path. The outer fluoropolymer jacket is flame-retardant, resists most chemically active corrosives, and protects against abrasion and impact damage. The cables can be cut to length in the field, and single overlapped without fear of burnout.
Chromalox Precision Heat and Control, 701 Alpha Drive, Pittsburgh, PA 15238. Tel: 412-967-3803; Fax: 412-967-5148.