In recent years, so-called "fuse resistors" have increasingly been used in electrical and electronic applications. The term "fuse resistor", however, which has become established in the market, is misleading. The actual function of a fuse resistor is that of a resistor in an electrical or electronic circuit. Only when an overload of multiple times the rated dissipation occurs can fuse resistors interrupt an electric current. In a wide range between the rated dissipation and the manufacturer's specified breaking dissipation, fuse resistors provide poor or no overcurrent protection. So if they are incorrectly rated and improperly used in an application, this may result in potential risk of fire. Fuse resistors perform the function of a fuse only within a particular overcurrent range, and, from a technical point of view, must therefore be referred to as "fuse resistors with particular overcurrent protection". Fuse resistors with particular overcurrent protection can safely interrupt high short-circuit currents, but are not capable of interrupting overload currents.
For safety reasons, they shall therefore only be used in combination with an accompanying overload current protection device, i.e. a true fuse, if overload currents cannot be excluded to occur in the respective application.