A Lightning Arrester is a device used on electrical power systems and telecommunications systems to protect the insulation and conductors of the system from the damaging effects of lightning. The typical Lightning Arrester has a high-voltage terminal and a ground terminal. When a lightning surge (or switching surge) travels along the power line to the Arrester, the current from the surge is diverted through the Arrestor, in most cases to the earth. They are used on tall buildings to prevent lightning from causing physical damage to infrastructure. Lightning arresters are available in many different forms and are used in a variety of application.