Operation principle
The principle lies in a resistance wire or stranded wire consisting of copper and resistance conductors, which runs through the whole length of the cable. In practice, heating cables with a lower ohmic value consist of stranded wire made of resistance and copper wires, cables with a higher ohmic value consist of a resistance wire spiralled on a fibreglass cord. The flexibility of the cable is ensured by a suitable electric insulation. The basic insulation of the heating cord is mostly made of silicon rubber. Exceptionally, fluorinepolymer insulation can be used. For the main requirement placed on this insulation is the resistance against higher temperature while simultaneously keeping the mechanical and electric strength.
The basic raw product for a heating cable is the C1S heating cord. It is a heating cord fitted with silicon rubber insulation. The cord alone finds use in products for household and refrigeration industry. Additional insulating layers depend on the particular use of the specific type of heating cable.
A heating cable for floor heating is furthermore fitted with thermoplastic insulation (KY). It can also be fitted with copper braiding and an outer thermoplastic jacket (KYCY). Heating cables are either supplied in length or terminated and prepared for a specific application.
The first category is primarily formed by cables for floor heating, heating of outside surfaces, subsoil heating, heating in cooling chambers etc. However, even these can be factory terminated and equipped with a cold feed and also with a return copper conductor allowing the power supply of a heating cable only from one end (KYCYR).
The second category includes various heating cables and tapes designated for domestic appliances (yoghourt makers, dryers, aquarium heating etc.), for cold storage industry (heating of freezing unit drains, doorframes, showcases etc.) or, for example, anti-condensation heaters of electric motors.
