How to Replace a Single-Pole Light Switch

Inspecting wiring on switch

Step 4: Inspect Switch Wiring

Check the terminals on the switch with a voltage tester to make sure the power is off. Examine the switch, noting which wire is attached to which screw. Before disconnecting the wires, flag or label them so you’ll remember which one is which. Since the switch pictured had a black and white wire running through it, the white wire was marked with black electrical tape to indicate it was hot.


Disconnecting wires from switch

Step 5: Disconnect Wires from Switch

Loosen the screws on the switch that hold the wires in place, and carefully remove the wires. If the wires were installed in the back of the switch with push-in terminals, insert a small, slotted screwdriver in the slot next to each terminal to release the wire. If a bare copper ground wire is attached to the switch, disconnect it as well.

If the end of the wires are in good shape, you can reuse them without cutting or re-stripping. However, if the ends are damaged, snip them back to good solid wire, and use your wire strippers to remove the sheathing to expose about 1/2” of bare wire.

If there are other wires inside the electrical box connected with wire nuts, check to see that the connections are tight by turning the wire nut clockwise. If the inside of the electrical box is dusty, vacuum it out.


Connecting wires to new wall switch

Step 6: Connect Wires to New Switch

Hold the new switch so the “off” position is pointing down. If you are attaching the wires using the mounting screws on the side of the switch, use the tips of stripping pliers or needle-nose pliers to gently bend a hook in the wires to fit around the connection screw. Bend the wires in a clockwise direction, so they will be pulled onto the terminals when you tighten up the screws.

Hook each wire around the connection screw, making sure your labels match the old switch, and tighten up the screws to secure the wires to the switch. If you have a ground wire, connect it to the green screw on the switch.

Alternatively, you can insert a straight wire beneath the brass plate next to the screw and tighten the screw to hold it in place, or use push-in connections on the back of the switch if available; but both methods are considered less secure than screw mounting.

7 COMMENTS

  1. It might have been a good idea to do a good lamp test first.This test is best accomplished by making sure the test lamp works in another socket. I might have noted that when the switch was removed from the wall the conductors were installed with the loop facing in the wrong direction, this might make clear the instruction to face the loop in what could be called a clock wise direction.
    thanks Joe vs

  2. Replacing a single pole switch should be fairly straight forward. SAFETY FIRST. Turn the power off at the electrical panel where the power originates. With the power off it is safe to remove the switch from the box that it is mounted in and to disconnect the wires from the switch. The national
    elec.code art. 200.7(c) requires the white to be hot only when in a cable and only for switching. Idealy connect white to top terminal black to bottom terminal bare ground to green screw on switch, reinstall switch, restore power and test by turning switch on. The switch should be up when it is turned on also you will read on and off as opposed to no and ffo on the switch. Wrap wire on terminals in a clockwise direction. WORK SAFE.

  3. Hi, I submitted an explanation for replacing a single pole switch with a black white and bare ground wire, if there are additional wires in this same box additional information would be required to provide a more detailed response. Happy to help if I can. Joe

  4. Hi, I am changing a wall switch that controls 2 balusters flourescent lights in the garage. I sued a single pole decorator off/on switch. One red wire on left and 2 black wires on right on original switch. . The screw on the left on the decorator switch is a ground and the original switch had the red on the ground screw also. Followed the same and not turning on. I did notice the switch originally was backwards meaning down for on and up for off. What am I doing wrong please?

  5. Scratch that question…Found another wall switch behind a cabinet in the garage I did not know about so will go with a double pole switch and sure it will work now. Thanks anyway.

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