Cables form an integral part of the electrical resistance heat treatment system and are supplied complete with connectors in two main areas - for the transmission of power from the heat treatment unit (low or mains voltage) and for the interconnections between thermocouple conductor wires, recording instruments, and programmers. In addition cables are produced as splitters for the parallel connection of heater groups or for star connection to a 3-phase mains electrical supply. The main extension cables may also be conveniently grouped as a triple cable set having a go and return power lead and a compensating cable. The cables can be supplied of lengths to suit but standard lengths of 10m, 25m and 30m are available. All cables have either twistlok connectors at each end to suit the system or polarised connected for compensating cables (copper-constantan).