Where is GFCI protection required?

A standard breaker watches one thing: how much total current a circuit is drawing. It trips to protect the wiring from overload. That trip threshold is far more current than it takes to seriously hurt a person.

A GFCI watches something different: whether the current going out matches the current coming back. Any imbalance means current is escaping the intended path (through water, through a damaged cord, potentially through you), and it trips on a tiny difference, fast enough to prevent a dangerous shock. It protects people, not wiring. The two devices do different jobs, which is why modern homes have both.

The principle is simple: where water and electricity are likely to meet. In practice that means:

Two honest caveats. First, the exact list has expanded with almost every code cycle, so we deliberately describe the areas rather than reciting a list that would be outdated at the next revision. Requirements also vary by code cycle and jurisdiction. Second, work being done today is held to the code in force today, while existing installations are generally not required to be brought up to current code unless work is being done on them. Your 1960s bathroom isn't automatically a violation; your remodel is a fresh start.

GFCI is about shock: current leaking out of the circuit to ground. AFCI is about fire: it listens for the sputtering electrical signature of an arc, the kind a pinched cord, a nail through a cable, or a loose terminal produces.

You generally find GFCI requirements in the wet areas listed above and AFCI requirements on living-area circuits. Some breakers now combine both. When one trips, knowing which type it was tells you which problem to go looking for: moisture and leakage for a GFCI, connections and cords for an AFCI.

GFCI protection can live in two places: in the receptacle itself (the familiar TEST/RESET buttons) or in the breaker at the panel, which protects the whole circuit. Both are legitimate; each fits different situations.

The part that surprises people: one GFCI receptacle can protect every ordinary receptacle wired downstream of it on the same circuit. That's why a tripped GFCI in the garage can kill outlets in a bathroom, on the exterior wall, and in the basement all at once, and why the first troubleshooting step for dead outlets is finding the tripped GFCI, not the panel.

Almost always there is a reason. Moisture in an exterior box is the classic culprit, especially after weather. A failing appliance leaking small currents to ground is next. Less commonly, the device itself is worn out; GFCIs are electronics and they age, particularly on exposed exterior circuits.

A GFCI that trips repeatedly, trips instantly on reset, or trips with nothing plugged in is giving you information. Resetting it over and over is silencing the messenger. That's a diagnosis job, and it usually has a findable cause: the kind we chase on the electrical repair page.

Grounded three-slot receptacles weren't required throughout a home until the 1962 NEC. Before that, they were required only in laundry areas from 1947, with outdoors, garages, and basements added in 1956. Pre-1962 houses commonly have ungrounded circuits, and Spokane has plenty of them: 19% of city housing was built before 1940.

Swapping a two-prong receptacle for a three-prong one on an ungrounded circuit, without more, is not a fix: the ground hole is connected to nothing, and it quietly tells everyone the outlet is grounded when it isn't. GFCI protection is the code-recognized way to make those receptacles safer without a ground, and it's often the practical answer. Where grounding genuinely matters (sensitive electronics, or a remodel with open walls), the longer-term answer is new grounded circuits, which is squarely an outlet installation conversation.

Press TEST: the device should trip and cut power to whatever is plugged into it (and to its downstream receptacles). Press RESET to restore. Thirty seconds, once a month.

A GFCI that won't trip has failed as a safety device. One that won't reset or trips instantly is telling you there's a fault downstream. Either one deserves attention, and exterior GFCIs, which live the hardest life, deserve the most frequent checks.