Arc Detection Circuit Breaker

An arc fault circuit interrupter afci also known as an arc fault detection device afdd is a circuit breaker that breaks the circuit when it detects an electric arc in the circuit it protects to prevent electrical fires.

Arc detection circuit breaker.

Afdds are protective devices installed in consumer units to provide protection from arc faults. Afcis are designed to sense an arc which is an electrical leak caused when a hot wire touches a neutral or ground but doesn t trigger the circuit breaker. An arc fault circuit breaker differs from a gfci in that it detects slow electrical leaks. An afci selectively distinguishes between a harmless arc incidental to normal operation of switches plugs and brushed motors and a potentially dangerous arc that can.

After having been slowly phased in over the past 3 nec code cycles these new arc fault breakers are now required on almost every 120v circuit in the finished space of the house. This series arc detection is beneficial to detect lower level arcing in both branch circuits and power supply cords. Combination afci protection is required by the nec as of january 1 2020. What are arc fault detection devices.

You may even recognize these arc fault circuit interrupter breakers with their visible test button in your circuit breaker panel. Breaker afci and gfci protection. For total interruption of current the circuit breaker it is essential to quench the arc as quickly as possible. A conventional circuit breaker isn t sensitive enough to detect electricity arcing through the air while the arc is still too small to ignite a fire.

A slow leak typically occurs when wiring is compromised but not completely shorted i e. When a nail punctures a wire behind the wall or a wire nut loosens and a small electrical current begins to build up heat. As long as this arc is sustained in between the contacts the current through the circuit breaker will not be interrupted finally as because the arc is itself a conductive path of electricity. They use microprocessor technology to analyse the waveform of the electricity being used to detect any unusual signatures which would signify an arc on the circuit.