Circuit Breaker

A circuit breaker is an electrical safety device that protects a circuit from damage caused by excess current, interrupting the flow of electricity to prevent overheating and fire, and unlike a fuse it can be reset rather than replaced after it trips. Thomas Edison described an early form of the device in an 1879 patent application, though his commercial power systems used fuses instead, and the German engineer Hugo Stotz developed the modern automatic circuit breaker, patented in Germany as patent 458392 and brought to market by Brown, Boveri & Cie in 1924. Circuit breakers are now made in ratings from small household devices protecting individual appliances up to heavy switchgear protecting the high-voltage circuits that feed an entire city.