GFCI’s are electrical safety devices which provide human safety from shock by detecting “loose” electricity and shutting the circuit down. They do this fast enough that in theory you will survive, assuming they are working properly and wired properly.

Power becomes “loose” when the amount of electricity flowing in the hot (black) wire differs from the power flowing in the neutral (white) wire. We do not actually consume electricity; we simply pay to move the electrons from hot to neutral.

When power is free to move from hot to ground, or worse, to you, the GFCI detects this loss of power (loose) and shuts the circuit down. This is completely different than the protection from a breaker or fuse, which is a fire safety issue. The breaker trips at 15 Amps, the GFCI trips at 5 milli-Amps, or 33/10,000’s the breaker rating.

GFCI’s, like any electronic device, do not appreciate exposure to extreme temperatures and humidity. As a result, a significant portion of the GFCI’s located outdoors and in bathrooms do not work properly when tested. These should be tested once a month, by pushing the test button. The reset button should pop out, and the circuit should be dead, and they should reset easily by pushing the reset button.  GFCI’s differ from arc fault breakers in a number of ways-see arc fault breakers.