In 1999, the National Electric Code (NEC) required the use of Arc Fault Circuit Interrupters (AFCIs) in bedrooms, effective adoption in January 2002. These are most frequently seen as breakers with funny green, blue or yellow buttons on them in your sub panel. Several years ago, a CPSC study identified arc fault detection as a promising new technology. Since then, CPSC electrical engineers have tested the new AFCIs on the market and found these products to be not perfect but very effective. AFCIs use unique current sensing circuitry to discriminate between normal electrical arcs and unwanted arcing conditions then de-energize the circuit like the GFCI breakers do. Their intended function is to prevent fires. In older homes with aging and deteriorated wiring and unprotected circuits, the use of GFCI and AFCI devices can be very beneficial.
Problems in home wiring like arcing and sparking, are associated with more than 40,000 home fires each year! A 1994 insurance company study determined that over 33% of fires in nearly 700 cases were from arcing faults. Arc faults most often occur in damaged or deteriorated wiring and cords creating very high temperatures which can ignite nearby combustible stuff. Just another reason for exterminating attic rodents and sealing up all exterior access points! Sometimes the damage comes from home decorators hanging pictures of the kids/grandkids when nails penetrate unseen wiring. Cords through doors and windows are not bright idea either. These source fires claim lives and dreams everyday but the good thing is there is an inexpensive alternative. 1994-1995 CPSC sponsored, UL run testing determined that a GFCI/AFCI combo was the bestest way (their word was “promising”) to reduce risk of fires. The electrical safety device called an arc fault circuit interrupter or AFCI is expected to provide enhanced protection from fires resulting from unsafe home wiring conditions and stupid people.
Typical household fuses and circuit breakers do not respond to early arcing and sparking conditions in home wiring. By the time a fuse or circuit breaker opens a circuit to defuse these conditions, a fire may already have begun. The AFCI's circuitry continually monitors current and can discriminate between normal arcs (when a switch is opened or a plug is pulled from a receptacle) and bad arcs. The sensing circuitry de-energizes the circuit super quick thus drastically reducing the potential for fires. An unwanted arc occurs when conductors touch themselves or another grounded metal surface.
If you live in a house built after 2002, look in your breaker panels. You should see breakers that have that ole familiar look of a GFCI breaker but the AFCIs are usually different colors and will be labeled “AFCI” and/or “Arc Fault Circuit Interrupter”. They offer the traditional overcurrent protection plus the arc fault protection. They are tested manually with these buttons just like the GFCIs too. (Tip: It's a good idea to save your computer work before you test.) Oh yeah, attorney's note: AFCIs are designed to limit faults but cannot completely eliminate them. Kinda like a home inspection.
Requiring AFCIs
AFCIs are already recognized for their effectiveness in preventing fires and are required for bedroom circuits in newer residential construction, but should also be considered for protection in older wiring systems. The older homes can especially benefit since wiring and insulation deteriorate with time and exposure. As a matter of fact…according to a 1990 Consumer Product Safety Commission (CPSC) study (149 fires/16 cities), 85% of all arc type fires occurred in houses 20 years and older. Tells me, age plays a significant role in the risk and if that's so…I'm already on fire! We will likely see future editions of the national electric code, which are updated every three years, expand required coverage. While both AFCIs and GFCIs are important safety devices, they have different functions. AFCIs are intended to address fire hazards; GFCIs address shock hazards. Combination devices that include both AFCI and GFCI protection in one unit will become available soon.
Should You Install AFCIs?
Be sure to have a qualified electrician install AFCIs; do not attempt this work yourself. The installation involves working with a liability your insurance will not cover. As usual, check one of my favorite web sites, Recalls for any recalled/defective devices known.
