Turn off power to the spa at the circuit breaker box. Make sure the spa power switch is off and pull open the front of the spa pack to view the wiring. Connect your cable's electrical circuit to the spa pack's conduit and use the clamp to secure it into place.
Cut the cable's jacket to about one inch ahead of the clamp. Separate the black, white and copper cables up to a length of eight inches. Remove about 1/2 inch of the sheath using the wire strippers to display the copper.
Connect the black wire into the "Line" terminal block and tighten the screw of the terminal.
Connect the white wire into the "Load" terminal block and tighten the screw of the terminal.
Attach the copper wire around the green screw and tighten the screw.
Close the spa control pack door, restore power at the circuit breaker box and turn on the spa to test its operation.