How to Wire a Garbage Disposal Safely: Expert Tips

How to Wire a Garbage Disposal?

To wire a garbage disposal, you can choose between hardwiring or using an appliance cord.

For hardwiring, connect the disposal to a switch in an electrical box and protect exposed wiring with conduit.

For plug-in disposals, plug the cord into an outlet controlled by a wall switch.

Purchase a grounded appliance power cord with the appropriate rating.

Connect the white and black wires to the power supply’s matching wires, ground the supply wire, and replace the electrical cover plate.

If there is a dishwasher, remove the line plug on the disposal and mount it using the three tabs.

Line up the discharge tube with the water pipes and ensure tight connections with plumbing pipes.

Use a rotating cam collar to lock the disposal into place, test for leaks, restore power, and always run water when using the disposal.

Avoid putting hands or fingers near the disposal opening for safety.

Key Points:

  • Choose between hardwiring or using an appliance cord for wiring a garbage disposal.
  • For hardwiring, connect the disposal to a switch in an electrical box and protect exposed wiring with conduit.
  • For plug-in disposals, plug the cord into an outlet controlled by a wall switch.
  • Purchase a grounded appliance power cord with the appropriate rating.
  • Connect the white and black wires to the power supply’s matching wires, ground the supply wire, and replace the electrical cover plate.
  • If there is a dishwasher, remove the line plug on the disposal and mount it using the three tabs.


Did You Know?

1. The first electric garbage disposal was invented in 1927 by John W. Hammes, a Wisconsin architect, who created it as a solution for his wife’s frustration with disposing of kitchen waste.

2. Garbage disposals were once banned in New York City for almost 20 years, from 1973 to 1997, due to concerns about the city’s aging sewer system.

3. The typical motor in a garbage disposal unit is capable of spinning the blades at a speed of around 2,800 revolutions per minute (RPM), which is fast enough to liquefy most food waste.

4. Contrary to popular belief, it is safe to put small chicken bones, including fish bones, down a garbage disposal. The grinding action of the disposal is usually powerful enough to crush them into tiny, harmless pieces.

5. The idea for a garbage disposal was inspired by a concept called “the pig feeding trough.” John W. Hammes got the notion when he was introduced to this contraption which was used to efficiently dispose of food waste in a Chicago slaughterhouse.

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Two Ways To Connect A Garbage Disposal: Hardwired Or Plug-In

When connecting a garbage disposal to the electrical power supply, there are two options available: hardwired or plug-in.

  • Hardwired: This method involves connecting the disposal to a switch installed in an electrical box. The switch is usually placed in the sink base cabinet or on a wall near the sink. Additionally, there is a junction box inside the cabinet. This setup provides a clean and seamless appearance as there are no visible cords or plugs.
  • Plug-in: Plug-in disposals come with a cord that can be easily plugged into an outlet located inside the sink cabinet. This outlet is controlled by a wall switch near the sink. The plug-in method offers the convenience of easy installation and replacement of the disposal without the need for professional assistance.

Protecting The Wiring Inside The Cabinet

When dealing with exposed wiring inside the sink base cabinet, it is crucial to ensure that it is adequately protected to prevent any damage or accidents. This can be achieved by using flexible metal conduit (BX cable) or non-metallic flexible conduit or tubing. These protective materials not only safeguard the wiring from potential hazards but also provide a neat and organized appearance inside the cabinet.

By employing flexible metal conduit or non-metallic flexible conduit or tubing, you can rest assured that the electrical wiring for your garbage disposal is secure and up to code. It is essential to prioritize safety when working with electrical connections, and this step should never be overlooked.

Choosing And Installing The Right Cord For A Plug-In Disposal

If you opt for a plug-in disposal, it is vital to select and install the appropriate cord to ensure safe and reliable operation. Keep in mind that cords for disposals are not typically sold with the unit and must be purchased separately. Thankfully, various kits are available that contain all the necessary parts for installation.

These kits typically include a grounded appliance power cord with a plug, a cord clamp, and plastic wire connectors. It is essential to choose a cord that matches the appropriate voltage and amperage ratings for your garbage disposal. Failure to do so could result in electrical hazards or damage to the unit.

Installing the cord to the disposal is generally easier before mounting it under the sink. However, it is still possible to complete the wiring after mounting. To do this, remove the disposal’s cover plate to access the wiring. Then, connect the white and black wires to the corresponding wires from the power supply. Finally, ground the supply wire and replace the electrical cover plate on the unit.

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Step-By-Step Guide For Wiring A Garbage Disposal

Installing a garbage disposal involves careful attention to detail and adherence to proper procedures. Follow this step-by-step guide:

  1. Ensure Power Supply is Off: Before starting any electrical work, make sure to turn off the power supply and disconnect it from the circuit breaker.
  2. Remove the Cover Plate: Locate the disposal’s cover plate and remove it to access the wiring.
  3. Connect the Wires: Connect the white wire from the power supply to the white wire on the disposal. Similarly, connect the black wire from the power supply to the black wire on the disposal.
  4. Ground the Supply Wire: Ground the supply wire by connecting the green or bare copper wire to the grounding screw on the disposal.
  5. Replace the Cover Plate: Once the wiring is properly connected, replace the electrical cover plate on the disposal.
  6. Double-Check Connections: Before using the garbage disposal, double-check all connections to ensure they are secure and properly attached.
  7. Additional Step for Dishwasher: If there is a dishwasher connection, refer to the next section for the additional steps involved.

Additional Step If Connecting A Dishwasher

If you have a dishwasher and plan to connect it to the garbage disposal, there is an important extra step for proper functionality. Begin by locating the close-ended tube on the side of the disposal where the dishwasher inlet line is connected. Use a screwdriver and a hammer to remove the line plug and create space for the dishwasher connection.

Mounting And Testing The Garbage Disposal

Once the wiring and optional dishwasher connection are complete, it’s time to mount the garbage disposal. Start by aligning it with the mounting assembly under the sink. The disposal features three tabs that help lock it into place.

Next, shift the disposal to align the discharge tube with the water pipes. For double-bowl sinks, you may need to cut PVC plumbing pipes to ensure a proper connection with the “J” trap.

Ensure all plumbing nuts are tight and that the disposal line is secure. To lock the disposal into place, use a screwdriver or wrench to tighten the rotating cam collar near the mounting assembly.

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To test for any leakage, turn on the faucets and let water flow through the disposal. If you have a dishwasher, turn it on as well to check the connection and tighten any problem areas to prevent water leakage.

Finally, once everything is secured and tested, restore power to the outlet under the sink and plug in the garbage disposal. Remember to always run water while using the disposal for safety reasons. Additionally, it is vital to keep hands and fingers clear of the disposal opening to avoid accidents.

Frequently Asked Questions

How are garbage disposals wired?

The wiring of garbage disposals can be done in two different ways. In one method, they are hardwired directly into a dedicated circuit. This means that the power supply is connected directly to the garbage disposal without the use of an appliance cord or wall outlet. Another option is to wire the garbage disposal with an appliance cord that plugs into a wall outlet. This is usually more convenient as the outlet is typically located inside the sink base cabinet.

Do you need electrical for garbage disposal?

Yes, electrical connections are necessary for a garbage disposal to function properly. An available outlet protected by a 120 volt, 20 amp circuit breaker is required for installation. It is important to note that simply having a GFCI outlet will not suffice. Before proceeding with the installation, ensure that the power is turned off and gather the necessary tools.

Does garbage disposal wiring need to be in conduit?

Yes, garbage disposal wiring should be in conduit for several reasons. Conduit provides the necessary protection to prevent mechanical damage to the wire, ensuring its longevity and reducing the risk of electrical hazards. Moreover, running the wire in flexible conduit from the wall connection allows for easy installation and flexibility, making future repairs or adjustments more convenient. Ultimately, incorporating conduit ensures the safe and reliable operation of the garbage disposal system.

How does a garbage disposal get power?

Garbage disposals receive power through a connection to an electrical outlet located under the kitchen sink. The unit requires a power supply cable to be plugged into the outlet, providing the necessary electricity to operate. Typically, residential garbage disposals require a circuit of 15 amps and 120 volts to function efficiently and effectively.

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