Surge plugs are used for the secondary protection of computers, video equipment, TV, alarms and other electronic equipment. They are available in the normal 16A round pin.

These plugs are fitted with an overcurrent and thermal fuse. In the rare event of varistor failure, the varistors are disconnected from the mains supply, preventing any dangerous temperature rise. The fault indication LED which is normally lit will go OFF to indicate the faulty protection has been disconnected. Mains power will still be available to the unprotected equipment.