Which device primarily protects against arc faults by recognizing arcing patterns and de-energizing the circuit?

• A. GFCI
• B. Safety switch
• C. Arc-fault circuit interrupter
• D. Circuit breaker

Answer: (C)

Arc faults can heat wiring enough to start a fire, so you need a device that looks for the distinctive arcing patterns and shuts the circuit off. An arc-fault circuit interrupter does exactly that—it monitors current waveforms for the irregular signatures of arcing and trips to de-energize the circuit, preventing fires. GFCIs protect people from shock by sensing an imbalance between hot and neutral, not by detecting arcing patterns. A standard circuit breaker trips on overloads or short circuits based on overall current, but it doesn’t specifically identify arcing events. A safety switch is just a disconnect for servicing, not primarily an arc-fault protector. Some devices combine AFCI with other protections, but the core function here is arc-fault protection provided by the AFCI.