CCHRC: What is an Arc Fault Circuit Interrupter? Cold Climate Housing Research Center says an arc fault circuit interrupter, or AFCI, is designed to detect dangerous electrical arcs and disconnect power to the circuit before a fire starts. They contain current and temperature sensors as well as a microprocessor that can distinguish arc faults caused by unintentional electrical hazards. (PDF)
Handyman Wire: Arc Fault Circuit Interrupters Handyman Wire site explains what an AFCI is and how they operate, as there has been some strong debate whether they should be made mandatory.
