Over-Current Protection of Wire with Circuit Protection Devices Utilizing the Temperature, Time and Current Relationship of Wire Heating

The temperature-current characteristics (TiC) chart and time-temperature-at-current (tTaC) chart provide a mean to evaluate the compatibility of an over-current protection device and a particular type of wire. These charts describe the wire temperature behavior independently of the damage temperature of the wire insulation. They can be used to determine the required insulation material to satisfy the operating properties of the protection device or to determine the adequacy of the protection device for a given wire insulation. This paper describes how these charts can be used to establish one of the aspects of the wire protection strategy for a new or an existing type of protection device.