A lightning arrester is a device used on electrical power systems to protect the insulation on the system from the damaging effect of lightning

Lightning

Lightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...

. Metal oxide varistors (MOVs) have been used for power system protection since the mid 1970s. The typical lightning arrester also known as surge

Voltage spike

In electrical engineering, spikes are fast, short duration electrical transients in voltage , current , or transferred energy in an electrical circuit....

 arrester has a high voltage terminal and a ground terminal. When a lightning surge or switching surge travels down the power system to the arrester, the current from the surge is diverted around the protected insulation in most cases to earth.

External links

• "Electrical Devices and How They Work, Part 14: Lightning Arresters" (article about lightning arresters and how they were used in early AC and DC power distribution systems), Popular Science
  Popular Science
  Popular Science is an American monthly magazine founded in 1872 carrying articles for the general reader on science and technology subjects. Popular Science has won over 58 awards, including the ASME awards for its journalistic excellence in both 2003 and 2004...
  
  monthly, February 1919, 5 unnumbered pages, scanned by Google Books
• OSHA Electric Power eTool: Illustrated Glossary: Lightning Arresters
• An extensive dictionary of terms used with arresters at ArresterWorks.com
• Graphic Overview of how an arrester works
• NEMA Surge Protection Institute