GFCI vs AFCI: Two Different Protections, Two Different Jobs

These two get confused constantly, including by people selling them. They solve completely different problems and they are not substitutes for each other.

GFCI: protects people

A ground fault circuit interrupter watches the current going out on the hot and coming back on the neutral. If those don't match — because some current has found another path, potentially through a person — it opens the circuit in milliseconds. It's calibrated to a level below what stops a heart.

Required in kitchens, bathrooms, garages, unfinished basements, laundry areas, outdoors, and generally anywhere within six feet of a sink.

AFCI: protects buildings

An arc fault circuit interrupter looks for the electrical signature of arcing — the intermittent, chaotic current pattern produced by a damaged cord, a loose terminal, or a cable pierced by a screw. Arcing generates extreme localised heat and is a leading cause of electrical fires.

Required in bedrooms and most living areas in modern construction. Older Massachusetts homes typically have neither until something prompts an upgrade.

Why yours keeps tripping

• GFCI nuisance trips usually mean moisture, a long circuit with accumulated leakage, or an appliance with a failing element. Freezers and older motors are frequent offenders.
• AFCI nuisance trips are often caused by vacuum motors, some LED drivers, and older appliance brush motors that mimic an arc signature.
• A GFCI that won't reset at all is either doing its job on a real fault or has reached end of life — they do wear out, typically after ten to fifteen years.
• Several outlets dead at once usually means one upstream GFCI has tripped and everything downstream is protected by it.

Test them

Both types have a test button, and both are meant to be tested monthly. Almost nobody does. If you press test and nothing happens, the device has failed and needs replacing — a dead GFCI provides no protection while looking completely normal.