Lightning Arrester

A lightning arrester is a device, essentially an air gap between an electric wire and ground, used on electric power transmission and telecommunication systems to protect the insulation and conductors of the system from the damaging effects of lightning.

Their purpose is to limit the rise in voltage when a communications or power line is struck by lightning or is near to a lightning strike.

Lightning arresters are generally located on both the high and low side of a substation transformer to protect it from strikes coming in either direction.