Circuit breaker definition

A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by an overcurrent or short circuit. It is a safety device that interrupts the flow of electric current in a circuit when the current exceeds a certain level, known as the trip point.

Circuit breakers are commonly used in electrical power distribution systems to:

  1. Prevent electrical fires: By interrupting the flow of current, circuit breakers can prevent electrical fires caused by overheating or arcing.
  2. Protect equipment: Circuit breakers can prevent damage to electrical equipment, such as motors, generators, and transformers, by interrupting the flow of current when an overcurrent occurs.
  3. Provide fault detection: Circuit breakers can detect faults in a circuit, such as a short circuit or ground fault, and interrupt the flow of current to prevent further damage.

Circuit breakers typically have the following features:

  1. Trip point: The maximum current level at which the circuit breaker will trip and interrupt the flow of current.
  2. Reset mechanism: A mechanism that allows the circuit breaker to be reset after it has tripped, allowing the circuit to be re-energized.
  3. Arc extinguishing: A mechanism that extinguishes the arc that occurs when the circuit breaker trips, preventing re-ignition and ensuring safe operation.
  4. Overcurrent protection: A feature that provides protection against overcurrents, such as those caused by a short circuit or ground fault.

There are several types of circuit breakers, including:

  1. Thermal-magnetic circuit breakers: These breakers use a combination of thermal and magnetic sensors to detect overcurrents.
  2. Electronic circuit breakers: These breakers use electronic sensors and microprocessors to detect overcurrents and trip the circuit.
  3. Molded case circuit breakers: These breakers are designed for use in industrial and commercial applications and are typically used in panelboards and switchgear.
  4. Air circuit breakers: These breakers use air as the medium to extinguish the arc when the circuit trips.
  5. Vacuum circuit breakers: These breakers use a vacuum as the medium to extinguish the arc when the circuit trips.

Overall, circuit breakers play a critical role in ensuring the safe and reliable operation of electrical power distribution systems.