AFCI protection detects which fault type?

• A. Ground faults.
• B. Overloads.
• C. Arc faults that can ignite fires.
• D. Voltage surges.

Answer: (C)

AFCI protection is designed to detect arc faults that can ignite fires. It monitors the current for arcing signatures—irregular, high-frequency, impulsive patterns that occur when insulation, loose connections, or damaged conductors arc. When such a pattern is detected, the AFCI trips to disconnect the circuit and prevent a fire. Ground faults, overcurrents, and voltage surges involve different phenomena: ground faults are leakage to earth detected by GFCIs, overloads are excessive current that trip standard overcurrent protection, and voltage surges are transient voltages typically handled by surge protection devices. AFCIs specifically target the dangerous arcing behavior.