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How To Replace a Light Switch or 3-Way Switch

When an old light switch (wall switch) no longer works properly or becomes damaged, it should be replaced. Replacement is usually very easy and should require only 5 to 10 minutes. Always replace a switch with one of the same type and rating.

Caution: Please read our safety information before attempting any testing or repairs.

Electrical work requires safe practices. Always turn off power at the circuit breaker or fuse box. Post a note that work is being done, to avoid someone turning the power back on. After turning off the power to the circuit, test the circuit to be certain that there is no power. Always use insulated tools for added safety. Check with your local building department for regulations and permit requirements before beginning work.

The steps for a 3-Way switch are the same as for a standard switch; the only difference is that 3-way switches have one additional wire to transfer over. It is not necessary to replace both 3-way switches at the same time, but it may be worthwhile if the other switch is old and could fail soon.

Steps to replace a wall switch

  1. Turn off the power at the circuit breaker or fuse box.
  2. Test the circuit to make certain the electricity is turned off at the breaker.
  3. Remove the cover plate.
  4. Remove the retaining screws at the top and bottom of the switch.
  5. Pull the switch straight out from the box.
  6. Note the position of the wires and transfer them over to the corresponding terminals on the new switch. To avoid making an error, instead of disconnecting all of the wires from the old switch, transfer one wire at time to the new switch.
    • We recommend using the screw terminals instead of the slip connectors found on the back of some switches, because wires are more prone to coming loose from slip connectors.
    • If the wire is stranded, twist the strands together.
    • Create a "U" shaped loop of bare wire about 1/2" long.
    • The screw tightens in the clockwise direction. Hook the loop under the terminal screw so that tightening the screw pulls the wire tightly under it, rather than pushing it out.
  7. Wrap electrical tape around the switch so that the exposed terminal screws are covered. This is a safety precaution to reduce the risk of shorts, arcing and shocks.
  8. Gently fold the wires into the box as you push in the switch.
  9. Secure the switch at the top and bottom with the retaining screws.
  10. Replace the cover plate.
  11. Turn on the power at the breaker or fuse box.
  12. Test the switch.

If the circuit breaker trips or fuse blows when you turn on the switch, the most likely cause is one of the wires is shorting against another wire or the metal box the switch is in. In the case of a 3-way switch, mis-wiring any of the wires could cause the breaker to trip or fuse to blow.

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