letter ar

Arc Fault An electrical arc which causes current to flow in unintended
ways, but often not in sufficient amounts to cause a standard
circuit breaker to trip. Arc faults result from worn or damaged
insulation and are a common cause of fires.


Arc Fault CircuitInterrupter (AFCI)A circuit breaker designed to provide protection from the effects of an arc fault by recognizing the characteristicsunique to arcing and de-energizing the circuit when an arc
fault is detected. The most effective AFCI circuit breakers are
combination AFCIs which provide protection against all three
known types of arc faults.


Autotransformer A type of transformer in which the secondary coil is part of the
primary coil. Often the secondary voltage is adjustable via a
movable tap.