What is the function of an AFCI device?

• A. It provides automatic voltage regulation to stabilize power.
• B. It reduces electrical noise on the line.
• C. It detects arcing faults and trips to prevent fires.
• D. It prevents ground faults by measuring impedance.

Answer: (C)

An AFCI is designed to improve fire safety by recognizing arcing faults and interrupting the circuit. Arcs from damaged cords or loose connections create irregular, high-frequency current patterns that can overheat insulation and start fires. The AFCI continuously monitors the current waveform and trips when it detects the distinctive arcing signatures, stopping the power to prevent a fire. This is different from automatic voltage regulation, which keeps voltage steady; or from devices that reduce electrical noise or monitor impedance to prevent ground faults, which are functions of other protective devices like line conditioners or GFCIs.