What is a GFCI and where is it required?

NationwideReviewed October 2026

A GFCI (ground-fault circuit interrupter) shuts off power within a fraction of a second when it senses current leaking away, such as through a person, preventing deadly shocks. The CPSC says it trips on a difference as small as 0.006 amps. The NEC requires GFCI protection in places like bathrooms, kitchen countertops, laundry areas, garages, crawl spaces, unfinished basements, outdoors, and near sinks, tubs, and showers. GFCIs come as breakers in the panel, as receptacles that also protect outlets downstream, and as portable plug-in units. Test each one monthly and after power outages by pressing test, then reset.

Check your local rule. This varies by state, county or city. Your permitting office has the final word; the official lookup pages below show you who that is.

Sources

Find the rule for your area

Official pages from the agencies and code bodies that set these rules.

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General information, written in our own words from the sources listed with each answer. It is not legal, engineering, tax or financial advice. Rules change and differ by state, county and city, so confirm with the office that issues your permit before you build. Last reviewed October 2026.