To wire a ground fault circuit interrupter, or GFCI, outlet in a circuit, shut off the power and pry out the old outlet. Remove all the wires from the outlet, remove the insulation from the terminals of the wires, and connect the wires to the GFCI outlet and other outlets. Switch on the power, and test the operation. Tools required for the installation include a GFCI tester, wire stripper, 4-in-1 screwdriver, utility knife and pair of needle-nose pliers.
Shut off the power to electrical outlet at the fuse box or main circuit panel, testing with a GFCI tester or lamp to ensure the power is off. Use a 4-in-1 screwdriver to unfasten the old outlet cover plate, unscrew the outlet and pull it out of the box. Disconnect all the wires to the outlet.
GFCI outlets generally have wires designated "line" and "load." Peel off 1/2 inch insulation from the ends of the hot and neutral wires, which supply incoming power, and connect them to the "line" terminals of the GFCI. To connect to other outlets, untape the terminals marked "load," and connect the hot and neutral "load" wires from other outlets to the terminals.
Secure the connections with electrical tape or wire nuts. Fold and insert the wires into the box, screw the outlet in place and replace the cover plate. Label the downstream outlets. Turn on the power, press the black button to test the installation, and press the red button to reset power.