Starting January 1, 2002, The National Electrical Code , Section 210-12,
requires that all branch circuits supplying 125V, single phase, 15 and 20 ampere
outlets installed in dwelling unit bedrooms be protected by an arc-fault Circuit
interrupter. Eventually they will be in more areas but the NEC selected to
require them on bedroom circuits first because a CPSC study showed many home
fire deaths were related to bedroom circuits. The AFCI (Arc Fault Circuit
Interrupter) breaker, will shut off a circuit in a fraction of a second if
arcing develops. The current inside of an arc is not always high enough to trip
a regular breaker. You must have noticed a cut or worn piece of a cord or a
loose connection in a junction box or receptacle arcing and burnt without
tripping the regular breaker. As you can guess this is a major cause of fires in
a dwelling. There is a difference between AFCIs and GFCIs. AFCIs are intended to
reduce the likelihood of fire caused by electrical arcing faults; whereas, GFCIs
are personnel protection intended to reduce the likelihood of electric shock
hazard. Don't misunderstand, GFCIs are still needed and save a lot of lives.
Combination devices that include both AFCI and GFCI protection in one unit will
become available soon. AFCIs can be installed in any 15 or 20 ampere branch
circuit in homes today and are currently available as circuit breakers with
built-in AFCI features. In the near future, other types of devices with AFCI
protection will be available. If a GFCI receptacle is installed on the load side
of an AFCI it is possible for both the AFCI and the GFCI to trip on a fault if
the current exceeds the limit for both devices. It is also possible for the AFCI
to trip and the GFCI to not trip since the two devices could race each other.
However, in no case is safety compromised.