The power switch for the garbage disposal is a common toggle type that looks exactly the same as a light switch, usually mounted on the backsplash, or the wall just above it. Such switches are sold at hardware stores and home improvement centers. The wiring is attached with screw terminals, and the electric configuration is basic.
Homeowners who replace their own electric switches save the high cost of hiring an electrician for a service call, so it's worth a try if your garbage disposal won't turn off or the wall switch for your garbage disposal is not working. However, don't hesitate to call an electrician if you feel this task is beyond your skill level.
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First Steps in the Process
Home Tips reminds you to work safely: You should shut off the breaker switch that controls power to the garbage disposal if it's labeled. If it isn't labeled, run cold water down the drain with the disposal, turn the disposal on and ask a helper to flip breaker switches until the unit goes off.
Shut off the main power breaker in the panel and perform the switch replacement during daylight hours if the correct breaker cannot be identified. Shutting off the main breaker will shut off all the lights, but that's preferable to working on a circuit that is possibly live. Leave a note or a lock on the breaker box to prevent anyone from restoring the power while you work.
Remove the Electrical Wires
Use a slotted screwdriver to remove the two screws holding the cover plate, then use a Phillips screwdriver to remove the two mounting screws that hold the switch to the wall box. Gently pull the switch out from the wall to expose the terminals and attached electric wires.
Check the terminals with a voltage tester to be certain the power is off. Take note of the wire colors secured to each terminal. The typical arrangement includes two black wires connected to top and bottom terminals on one side and a bare ground wire on the green ground terminal.
Remove the wires by loosening them from each terminal with a slotted screwdriver. When replacing the wires, it's hard to make a mistake. The two black wires are interchangeable (it doesn't matter to which of the terminals either one connects), and the bare wire always connects to the green grounding screw.
Replacement Switch for Garbage Disposal
Purchase a replacement switch with the same amperage rating as the old one. Some garbage disposals run at 15 amps while others require a 20-amp circuit and switch. You should be able to find the switch you need in home centers and hardware stores in your area, if not online.
All switches are not the same, and codes require disposal switches to have a marked off position. Bring the old switch to the hardware store for reference if you have any questions about its type.
Installing the New Switch
Cut off the bare wire ends and strip off 1/4 to 3/8 inch of insulation with wire cutters to expose new wire ends for connection to the new switch. Wrap bare wire around the terminals in clockwise rotation and tighten the screws so the heads cover all wire threads.
Press the wires gently into the wall box and secure the new switch by replacing the mounting screws. Put the cover plate over the toggle and secure its holding screws. Turn the power back on at the breaker box and test the switch by running cold water into the sink that holds the garbage disposal and flipping the new switch to the on position.