AFCI (Arc Fault Circuit Interrupter)

A breaker that detects dangerous arcing in wiring and trips before it can start a fire — required on most living-area circuits.

AFCIs protect against the kind of arc fault that comes from a damaged wire, a loose connection, or a nail through Romex. Different physics from a GFCI, different purpose. Required by NEC on bedroom, living room, and most living-area circuits.

Combination AFCI/GFCI breakers cover both and are increasingly the default for new residential construction.

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