A circuit breaker is an essential piece of equipment that is used to protect an electrical circuit.
Circuit breakers come in all shapes and sizes. Circuit Breakers can be used to protect the circuit(s) in a small single family residence or large switchgear which is put in place to protect high voltage circuits supplying a whole city.
Similar to the circuit breaker is the fuse. However, there is a major difference. A fuse will protect is electrical circuits one time only. After a fuse has protected the electrical circuit from damage it must be replaced. Circuit Breakers are different in that manner. Once a Circuit breaker has been used it can be reset and be ready to continue its normal operation. These circuit breakers can be reset manually and some automatically.
The way a circuit breaker functions is brilliant, yet simplistic. There are some differences between types of circuit breakers and current rating, but the core functionality is pretty much the same. A fault condition needs to be discovered by the Circuit Breaker. The fault condition is usually discovered in the enclosure of the breaker itself when dealing with low voltage circuit breaker systems. However, if you are dealing with a fairly large or high voltage circuit breaker, it works a differently. High voltage circuit breakers have more than way to discover a fault condition. If a fault is discovered contacts need to interrupt the circuit by opening. The circuit breaker uses its stored energy to break up the contacts. Some energy may be harnessed and used by the fault itself. When the current is interrupted an ark with be created. This ark needs to be controlled cooled down and made to dissipate. To reset the contacts need to be reclosed manually or in some cases automatically.