Scientific Assessment Confirms AFCI Technology Prevents Electrical Fires

A recent study conducted at the request of the National Association of State Fire Marshals (NASFM) confirms that the Arc Fault Circuit Interrupter (AFCI) technology incorporated under Article 210-12 in the 1999 and 2002 National Electrical Codes effectively prevents most fires that originate in electrical wiring, thus saving lives and property. Last year, NASFM, along with the U.S. Consumer Product Safety Commission, openly endorsed the technology. However, questions raised by some individual contractors and the National Association of Home Builders (NAHB) as to the cost, availability and effectiveness of AFCI technology prompted the NASFM Consumer Product Safety Task Force, in conjunction with the NASFM Science Advisory Committee, to conduct a review of the concerns. Both committees comprise experts from a broad spectrum of diverse disciplines. Electrical engineers from industry and government were consulted as part of the assessment.

The results of the investigation are now published in a NASFM document entitled, "AFCI Inquiry and Report," dated August 1, 2002. The report will be distributed to state and local government, electrical code officials, trade associations, and fire service agencies.

Available documents for download in PDF format: Visit

Finding (see page 7): The data in support of AFCIs are compelling. While conventional circuit breakers are designed to detect overloads and short circuits, AFCIs are designed to protect against fire by continuously monitoring the electrical current in a circuit and shutting off the circuit when many unintended arcing conditions occur.

According to the National Fire Protection Association and National Fire Incident Reporting System data, during the five-year period from 1994-1998, there were an average of 73,500 total electrical fires annually, which were responsible for 591 deaths, 2,247 injuries, and property damage totaling $1,047,900,000.1 The electrical problems that lead to these fires went undetected by conventional circuit breakers. Of these 73,500 electrical fires, 60,900 or 82% were caused by arcing and not by overloads or short circuits.

Mike Holt's Comment: I can agree with the above figures. The problem is that the current UL standard 1699 for AFCI, defines arcing at loose terminals and connections as a "glowing connection", it's not considered an arc. Therefore an AFCI device is NOT required to protect against this condition.

Additionally, the US Consumer Product Safety Commission technical staff, after conducting a great deal of independent research on AFCIs, estimates that 50-75% of residential electrical fires can be prevented by employing AFCI technology. That means that of the 73,500 electrical fires annually, AFCIs could potentially prevent 55,125 fires and save more than 440 lives, 1,685 injuries, and $785,925,000 in property damage, when AFCIs work their way into electrical codes for installation throughout the house. (See Appendix C.)

Mike Holt's Comment: I spoke to William H. King, Jr., Chief Engineer for Electrical and Fire Safety, Division of Electrical Engineering, US Consumer Product Safety Commission today and he said that the "AFCI technology" could possibly achieve this reduction in fires, but not the current AFCI device mandated by the NEC.

Mike Holt's Summary: An AFCI circuit breaker will protection against short circuits, ground faults and arcing, but it will not prevent a fire from loose terminals or connections. I wonder what percentages of fires are caused because of loose terminals and connections versus an arc.

Copyright © 2002 Mike Holt Enterprises,Inc.
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