Over temperature sensing system for power cables

Claim 1

An assembly which comprises an over temperature sensing device adapted to monitor, detect, alarm and otherwise respond to an over temperature condition and a single or multiwire conductor, comprising: (a) a sensing wire contiguous to and coextensive with a power cable comprising a single or multiwire conductor within a protective jacket, said sensing wire having a first detector wire and a second detector wire both of which are connected to an electric power source said first and second detector wires being uniformly spaced apart over their full lengths by a thermal-sensitive polymeric material selected from the group consisting of nylon polyamide resin, polyvinyl chloride, cellulose esters, cured acrylonitrile butadiene rubber containing at least one per cent acrylonitrile and substantially no sulfur, cured acrylonitrile butadiene rubber containing at least 0.5 per cent carboxylic acid monomer units and polyvinyl chloride blends of said rubbers extruded as a cover concentric to and coextensive with said first detector wire; (b) a solid state control device having two terminals in electrical circuit with said power cable and means for continuously monitoring and displaying changes in electrical resistance through said thermal-sensitive cover; and (c) alarm emans operatively connected to said solid state control device for identifying an over-temperature condition in said power cable.