GFCI vs AFCI: When Each Is Required

What a GFCI does

A ground-fault circuit interrupter protects people from shock. It compares the current going out on the hot with the current returning on the neutral. If even a tiny amount, a few milliamps, is leaking somewhere, maybe through a person, it trips in a fraction of a second.

Think water and people. GFCIs guard the places where you could become the path to ground.

Where GFCI protection is required

GFCI protection is required in the wet and damp areas of a dwelling, and the list has grown every cycle. Common spots include:

• Kitchens, bathrooms, laundry, and garages.
• Outdoors and in unfinished basements and crawl spaces.
• Near sinks, and around pools, tubs, and spas.

Newer editions also pull in more 240 volt appliances and areas. Always check the edition your jurisdiction enforces because these locations keep expanding.

What an AFCI does

An arc-fault circuit interrupter protects property from fire. It senses the erratic electrical signature of a dangerous arc, the kind a nicked wire behind drywall or a loose connection makes, and shuts the circuit down before that arc ignites the framing.

Think wires and fires. AFCIs guard the hidden connections in walls where you will never see the problem coming.

Where AFCI is required and how to combine

AFCI protection is required for most 120 volt circuits in the living areas of a dwelling: bedrooms, living rooms, dining rooms, hallways, closets, and similar spaces. Between the two protectors, a modern home ends up covered nearly everywhere.

Where a spot needs both, like a kitchen or laundry, use a dual-function breaker or device that provides GFCI and AFCI together. Do not substitute one for the other; an inspector will catch it, and more importantly it leaves a real hazard unprotected.