What is a circuit breaker

A circuit breaker is an electrical device designed to protect an electrical circuit from damage caused by an overload or short circuit. It is a safety device that automatically interrupts the flow of electrical current when it exceeds a certain level, preventing damage to the circuit or equipment connected to it.

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

  1. Protect against overcurrent: When a circuit is overloaded or has a short circuit, the breaker trips (opens) to prevent damage to the circuit or equipment.
  2. Prevent electrical fires: By interrupting the flow of current, circuit breakers help prevent electrical fires caused by overheating or arcing.
  3. Reduce downtime: Circuit breakers can quickly reset, allowing the circuit to be restored to service without the need for manual intervention.

Types of circuit breakers:

  1. Molded case circuit breakers (MCCBs): These are the most common type, used in residential and commercial applications.
  2. Air circuit breakers (ACBs): These are used in industrial and commercial applications, often in high-voltage systems.
  3. Miniature circuit breakers (MCBs): These are smaller, used in residential and commercial applications, often in smaller circuits.
  4. Ground fault circuit breakers (GFCBs): These detect ground faults (leaks to ground) and trip to prevent electrical shock.

How circuit breakers work:

  1. Current sensing: The breaker contains a current-sensing device, such as a thermistor or a current transformer, that monitors the current flowing through the circuit.
  2. Trip point: The breaker is set to trip (open) when the current exceeds a predetermined level, known as the trip point.
  3. Tripping mechanism: When the current exceeds the trip point, the breaker's tripping mechanism is triggered, causing the breaker to open and interrupt the flow of current.

In summary, circuit breakers are essential safety devices that protect electrical circuits from damage and prevent electrical fires by automatically interrupting the flow of current when it exceeds a certain level.