How to Install a GFCI
Wiring for a ground fault circuit interrupter (GFCI) depends on where it falls in the circuit and whether you want it to protect the other outlets.
Turn off the power and look into the box to see whether the receptacle is at the start, at the end, or in the middle of a run. If it is in the middle or at the start, it can protect other outlets. Consider any drawbacks to protecting outlets in the circuit after the GFCI. Do you risk cutting off power to a freezer if the GFCI trips, for instance? The following shows how to protect a single outlet.
What You Need
- Side cutters
- Lineman's pliers
- Voltage detector
- GFCI receptacle
- Wire nuts
- Electrician's tape
Step 1: Disconnect Wires
Turn off the power. Test to make sure the power is off. Look inside the box to see where in the circuit the outlet falls. This box has two cables coming into it, making it a middle-of-run outlet. Disconnect the wires.
Step 2: Pigtail Wires
If you want GFCI protection only for the outlet you're installing and not the ones down the line, pigtail all the white wires together and connect the pigtail to the terminal labeled WHITE LINE.
Step 3: Connect to Hot Line
Pigtail all the black wires together and connect the pigtail to the terminal marked HOT LINE.
Step 4: Finish and Cover Box
Pigtail all the ground wires together and connect the pigtail to the green ground screw. Wrap tape around the GFCI to cover the terminals. Attach it to the box and cover with a cover plate.
What if There is Only One Cable in the Box?
If only one cable enters the box, the receptacle is at the end of the line. Connect the black wire to the BLACK LINE terminal and the white wire to the WHITE LINE terminal. Connect the ground wire to the ground screw, pigtailing it to the box if the box is metal.