Step 1
Turn the circuit breaker supplying power to the wiring for the outlet to the off position. The circuit breaker is in the main service panel, and labeled on the inside of the service panel cover door.
Step 2
Remove the screws holding the outdoor outlet electrical box cover in place. Set the cover aside. Pull the electrical wiring out of the box, so you have access to about 6 inches of the cable.
Step 3
Strip 4 inches of the outer insulation off the cable. This will expose the three interior wires inside the cable: black and white wires, which are insulated, and a bare wire. Strip 1 inch of insulation off the black and white wires.
Step 4
Connect the black (hot) wire to the brass screw labeled line or hot, and the white (neutral) wire to the sliver screw labeled line or neutral. Connect the bare wire to the green (ground) screw. Tighten each screw down onto the wires to hold them in place.
Step 5
Push the wiring into the outlet box, insert a screw into the top and bottom of the GFCI outlet, and tighten them down into holes on the outlet box. Replace the outlet box cover and insert a screw into each hole and tighten them down.
Step 6
Plug in the power cord from the pump to the GFCI outlet. Turn on the power at the circuit breaker and test for operation.