Turn off the power to the necessary circuit at the home's distribution panel. Confirm the power is off by touching a non-contact voltage detector to the wire's insulation.
Remove the access cover from the side of the spa and locate the electrical connections. Refer to your spa's manual for the exact location if you are having trouble finding the connections.
Loosen the terminals with a screwdriver. Cut the spa's wire to the desired length using the wire cutters. Strip 3/8 inches of insulation off the conductors in the wire.
Push the green wire into the ground terminal and tighten it down.
Push the black wire into the hot (L1) terminal and tighten it down. Push the red wire into the hot (L2) terminal and tighten it down.
Push the white wire into the neutral terminal and tighten it down. Your spa, however, may not have a neutral connection. This is dependent on if your spa needs a 120-volt connection to power a radio, CD or DVD player and/or a television.