What is a circuit breaker? A circuit breaker is an electrical switch used to protect an electrical circuit from damage caused by over current and short circuits. The function of a circuit breaker is to interrupt current flow after protective relays detect a fault. Thomas Edison described the early form of a circuit breaker in 1879. What are common types of circuit breakers? There are three primary circuit breaker varieties: Standard breakers, which include both single-pole and double-pole circuit breakers Ground fault circuit interrupter circuit breakers (GFCIs) Arc fault circuit interrupter circuit breakers (AFCIs) Common materials used for circuit breakers The material used to form the case and cover of a molded case circuit breaker includes a filler such as glass fibers, used for strengthening purposes. To ensure that the incoming plastic material contains the requisite filler material, a fluorescent material is included with the filler. Where are circuit breakers used? MCB: MCBs are the most commonly used circuit breakers in low voltage circuits. There are multiple smaller circuits in a single circuit, each controlled with an MCB, meaning that in the case of a fault, it will only be affected when the circuit is disconnected. Circuit breakers are used for switching off different kinds of loads from industries, buildings, commercial complexes, and hotels, etc. Industrial applications of circuit breakers The substations have these high volt circuit breakers playing an essential role in protecting the equipment and connective buses from a range of electrical faults that include overloads, earth and ground faults. Usually, the high voltage circuit breakers are generally classified by their arc extinguishing method. Sometimes MCBs along with air circuit breakers are used in industries, depending on the electric utility required by the operational function.