nterrupter) An AC receptacle or circuit breaker that cuts power off (trips) when it detects leakage from the hot side to ground, which causes a difference between the hot and neutral sides. Also called an "appliance leakage current interrupter" (ALCI) or residual current device (RCD), a GFCI receptacle is required in wet areas, such as bathrooms and kitchens.
GFCI receptacles and breakers are more sensitive than their regular counterparts because cutting the power faster may save a person from being shocked into a heart attack.
In the Electrical Panel
Like a regular circuit breaker, a GFCI breaker also trips when there is a current overload, whereas the GFCI receptacle does not.
GFCI in the Bathroom
GFCI receptacles are required in wet areas, such as bathrooms and kitchens, where water can short a nearby electric appliance. Pressing Test connects hot to ground to see if the device cuts the power off.
GFCI Circuit Breaker
A GFCI circuit breaker is wired to neutral in the panel for ground reference (hidden in this image). The white test button is pressed to test the unit, and it blinks if a problem arises. GFCI breakers are very expensive compared to standard panel breakers.