How Does a GFCI Work?
A GFCI circuit tester constantly monitors the flow of electricity through the circuit. If the flow spikes, or the ground becomes unstable, the GFCI will trip a mini circuit breaker built into the unit, and power to that particular outlet will be terminated until the GFCI is reset. This can also happen if too great a load is placed on a wiring circuit, turning off power at the receptacle rather than at the circuit breaker panel.
