Arc Detection Circuit Breaker

Combination afci protection is required by the nec as of january 1 2020.

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. An arc fault circuit breaker differs from a gfci in that it detects slow electrical leaks. You may even recognize these arc fault circuit interrupter breakers with their visible test button in your circuit breaker panel. Arc fault circuit breaker afci breaker is the latest arc fault detection device its main function is to detect and identify dangerous earthing arc faults parallel arc faults and series arc faults and to drive the device operation that cut off current timely to avoid electrical fires.

Although current sensing circuitry enables afcis to detect arcing conditions unintended trickles of current may also cause the breaker to shut off afcis are very sensitive. 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. When a nail punctures a wire behind the wall or a wire nut loosens and a small electrical current begins to build up heat. This series arc detection is beneficial to detect lower level arcing in both branch circuits and power supply cords.

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. 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. 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. An afci can be used in conjunction with gfci protection to provide both arcing fault protection as well as 5ma ground.

What are arc fault detection devices. A slow leak typically occurs when wiring is compromised but not completely shorted i e. Afdds are protective devices installed in consumer units to provide protection from arc faults. 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.