Motor protection switches are used in electric motors to protect against thermal overload. Thermal overload can be caused by a high mechanical load or the failure of external conductors. Without a motor protection switch, the electric motor could be damaged. The switch monitors the power consumption in the supply lines of electric motors. If more current is flowing than peviously set, the system shuts down. Motor protection switches are used for short-circuit protection of transformers in air conditioning systems, for example.