Self-regulating heating cables

Self-regulating or self-limiting? These terms are often used as synonyms, with self-limiting most accurately describing how it works. Self-limiting heating cables consist of two parallel bus wires embedded in a heating matrix doped with carbon particles. Above this is the insulation and (depending on the design) aluminium foil or protective braid and finally the outer jacket. When the temperature rises in operation, molecular expansion increases the distance between the carbon particles. The resistance increases and output drops. When temperatures fall, this process is reversed and output increases. This procedure regulates or limits the heat depending on the ambient temperature and prevents overheating of the trace heating.