IGA test protectors have a protective coil and also a miniature circuit breaker. The protectors detect a transient over-voltage and then switch off power supply. This will help protect the equipment. After every single protective actuation, the protector will have to be reset by simply operating the reset button. This way it is ready again to protect the equipment.
There are IGA test protectors for permanent over-voltage as well. They work in combination with ATSUB-D transient over-voltage protectors. The miniature circuit breaker is available in the following discharge currents: 25,32,40,50 and 63A.