How a GFCI Works
A GFCI outlet essentially monitors the amount of current flowing from hot to neutral through the outlet. A properly functioning appliance will maintain all electricity currents flowing from hot to neutral. If there is an imbalance in this process, the GFCI will trip the circuit to stop the flow of electricity. GFCI outlets are very sensitive and can detect an imbalance of just 4-5 milliamps and can trip the circuit in up to one-thirtieth of a second.
GFCI for Safety
These outlets are highly beneficial to have throughout the home since they can instantaneously cut of the electrical current flow upon detection of a mismatch in the flow of electricity. Having one GFCI outlet in most rooms and one outdoors in a garage is an important safety precaution to take with home electrical wiring. In fact, the National Electrical Code requires GFCI outlets in all wet or damp locations, such as bathrooms, kitchens, basements, garages, and laundry rooms, so it is likely your home has this outlet if it is up to electrical code. If not, install them asap.
The GFCI can even protect you from electrical shock if you happen to become caught between a hot wire and the ground. Electrical currents flowing from hot wires through you to the ground could be fatal. If you’re using a device plugged into a GFCI outlet, however, the circuit interrupter will detect that the current is not flowing from hot to neutral as expected, and will trip the circuit to cut the flow of electricity, potentially averting a fatal electrical shock.
An Easy Safety Standard
Installing or replacing GFCI outlets is easy and doesn’t require an electrician to do. You need to shut off the power to the specific room, unscrew the wall mounts, gently pull out the switch, and verify with an electrical probe that the power is off. You can then remove the wires from the current switch box, identify the line wires, and prepare the wires for connecting to the new GFCI. Connect the black hot wire to the brass screw, the neutral white wire to the silver screw, and the ground wire to the green ground screw.
If there are four wires in the box, connect the second black and white wires to the respective brass and silver screw terminals. Make sure all wires are completely secured to the switch box. Finally, push the GFCI into the wall box and attach the mounting screws. Replace the wall plate, restore power, and press the ‘reset’ button on the GFCI. If it does not reset, there may have been a problem with the line and load leads. Shut off power and check the connections, or call a professional electrician.