Editing Circuit breaker (section)

==Origins==
An early form of circuit breaker was described by [[Thomas Edison]] in an 1879 patent application, although his commercial power distribution system used [[fuse (electrical)|fuses]].<ref>Robert Friedel and Paul Israel, ''Edison's Electric Light: Biography of an Invention'', Rutgers University Press, New Brunswick New Jersey USA,1986 {{ISBN|0-8135-1118-6}} pp.65-66</ref> Its purpose was to protect lighting circuit wiring from accidental short circuits and overloads. A modern miniature circuit breaker similar to the ones now in use was patented by [[Brown, Boveri & Cie]] in 1924. Hugo Stotz, an engineer who had sold his company to Brown, Boveri & Cie, was credited as the inventor on German patent 458392.<ref>{{cite web|url = http://www.abb.de/cawp/deabb201/061462650496e146c12570880035eede.aspx|title = "1920-1929 Stotz miniature circuit breaker and domestic appliances", ABB, 2006-01-09, accessed 4 July 2011|access-date = 2011-07-04|archive-date = 2013-10-29|archive-url = https://web.archive.org/web/20131029194804/http://www.abb.de/cawp/deabb201/061462650496e146c12570880035eede.aspx|url-status = live}}</ref> Stotz's invention was the forerunner of the modern thermal-magnetic breaker commonly used in household load centers to this day.

Interconnection of multiple generator sources into an electrical grid required the development of circuit breakers with increasing voltage ratings and increased ability to safely interrupt the increasing short-circuit currents produced by networks. Simple air-break manual switches produced hazardous arcs when interrupting high-voltage circuits; these gave way to oil-enclosed contacts, and various forms using the directed flow of pressurized air, or pressurized oil, to cool and interrupt the arc. By 1935, the specially constructed circuit breakers used at the [[Boulder Dam]] project used eight series breaks and pressurized oil flow to interrupt faults of up to 2,500 MVA, in three AC cycles.<ref>{{cite book |editor-first=Charles H. |editor-last=Flurscheim |title=Power Circuit Breaker Theory and Design |edition=Second |publisher=[[Institution of Engineering and Technology (professional society)|IET]] |year=1982 |isbn=0-906048-70-2 |chapter=Chapter 1}}</ref>