How to Wire a Double Pole Electric Switch

Strip the insulation from all of the wires about 1/2-inch from the ends. You should have four colored wires and a single green ground wire for the double pole single throw switch. The double-pole double-throw switch will have six colored wires. Twist the wire ends between two fingers so that loose wires will not protrude from the terminals.

Loosen the green terminal screw and wrap the stripped end of the green wire around the screw. Tighten the screw, making sure that all of the wire strands are under the screw. Check the other terminals to determine if they are the screw type or the spade lug type.

Loosen the remaining screws on the terminals and wrap the wires around the appropriate screws. Carefully tighten the screws. If the terminals use spade lugs, insert a spade lug on each of the remaining wires and tighten the lugs around the wires using the crimping tool. Insert the lugs on the proper terminals and press them in place. Use the lineman's pliers to ensure that the spade lugs are firmly seated. The power source wires connect to the center terminals and the load wires connect to the outer terminals.

Mount the switch in a proper enclosure. If the switch is a double-pole double-throw switch, the alternate load wires connect to the remaining pair of outer terminals. Apply power and determine if the switch is operating properly.