How To Wire a Garbage Disposal | Family Handyman (2024)

Updated: Oct. 20, 2023

These powerful little machines make quick work of food scraps. Wiring them's a snap, too. Here's how.

For millions of homeowners over the last half-century or more, garbage disposals have been nothing short of a miracle. I love them so much it’s the first thing I upgraded in my new home, along with an under-sink hot water dispenser. Gone are the days of smelly trash cans — just scrape your plate right into the sink and flip a switch. How did we ever live without them?

All that grinding takes its toll, though. If your garbage disposal has seen better days, don’t be afraid to swap it out. Wiring one is very straightforward, and you can do it in an hour. (Of course, that doesn’t include replacing the actual garbage disposal, but that’s not a hard job, either.)

Whether you have a hardwired a cord-connected model, we’ll walk you through the process of wiring a garbage disposal.

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Here’s what you’ll need:

Turn Off the Breaker or Unplug

If your garbage disposal is hardwired to your under-cabinet circuit, turn off the breaker before proceeding. Look in your electrical panel for a labeled circuit breaker and shut it off. Many garbage disposals share a circuit with the dishwasher. If you don’t see a circuit specifically labeled for the disposal, look for the one for the dishwasher.

Test a non-contact voltage tester on a known live circuit (like a plugged-in cord on your microwave or toaster) to make sure the tester is functional. Then, under your sink, hold the tester to the cable that goes to your garbage disposal. If the tester beeps, turn off individual breakers and hold the tester to the cable until you find the breaker that controls the garbage disposal circuit. Save your knees and back by enlisting a helper for this part!

If you’re replacing a cord-connected garbage disposal, all you have to do is unplug it at the receptacle under the sink.

Disconnect the Cord or Cable

If your new garbage disposal comes with a cord and connector (many do not!), or you bought a new cord and connector, just throw the old cord away along with the disposal. If you want or need to re-use the cord, check for damage. Superficial scrapes are okay, but if you find any deep cuts or exposed interior wires, get rid of the cord.

To disconnect the cord or hardwired cable, remove the old cover plate from the disposal. It is likely held in place by a single machine screw. Double-check the power with your tester, then pull out the spliced wires.

Cut the white and black wires inside, near the wire nuts. Don’t bother unscrewing them; you’ll want fresh cuts for your new splice. Unscrew the green grounding screw and remove the ground wire. Then, unscrew the connector holding the cord or cable to the disposal and pull out the cord or cable. Keep the connector, if needed.

Prep the Cord or Cable

Using wire strippers, remove one-half inch to three-quarters inch of insulation from the white, black and green wires. If using a cord, the green wire likely has a ring connector on the end; if so, leave that in place. For hardwired connections, make a hook in the end of the green wire (like an umbrella handle), with your wire strippers.

Insert Cord or Cable Into Disposal

Remove the new disposal’s cover plate by unscrewing the machine screw. Set aside. Look for the circular hole next to it and insert the cable connector or clamp that you saved, or that came with the new cord assembly. Tighten the connector to the disposal with pliers.

Thread the cord or cable end through the connector, and pull the ends of the wires up through the opening where the cover plate was. About an inch of the cord or cable’s protective outer covering should be inside the compartment. Tighten the cable connector’s clamping mechanism around the cable or cord, making sure it is pinching the protective covering, not the wires.

Splice Wires

Attach the green ground wire from the cord or cable to the grounding terminal screw on the garbage disposal. If you have a hooked end, loosen the grounding screw and hook the ground wire clockwise around the screw. If you have a ring connector, remove the screw entirely and thread it through the ring. Tighten the screw to the garbage disposal.

Pull out the black and white wires from inside the garbage disposal. Splice the cord or cable wires to the garbage disposal wires, matching black to black and white to white. Hold the wires firmly and spin on an appropriately-sized wire nut. These will come with the cord assembly, but I prefer using sturdier wire nuts made by Ideal or 3M. Pull on each splice to make sure it is secure and won’t come loose. Replace the cover.

Install Garbage Disposal

Install garbage disposal according to the directions or our handy guide. Once everything is in place and buttoned up, turn on the breaker and test the garbage disposal. Or, simply plug it in.

How To Wire a Garbage Disposal | Family Handyman (2024)

FAQs

How To Wire a Garbage Disposal | Family Handyman? ›

Garbage disposals should be either hardwired or connected to an outlet through a grounded electrical outlet. A dedicated circuit is generally recommended, although a circuit that is shared with a dishwasher is sometimes appropriate. The best authority on this distinction is the disposal's user manual.

Should garbage disposal be hardwired or plug in? ›

Garbage disposals should be either hardwired or connected to an outlet through a grounded electrical outlet. A dedicated circuit is generally recommended, although a circuit that is shared with a dishwasher is sometimes appropriate. The best authority on this distinction is the disposal's user manual.

What are the electrical requirements for a garbage disposal? ›

Most household garbage disposals run on 120 volts and draw between 5 and 10 amps of current. A typical 1/2 horsepower garbage disposal will draw around 6 amps of current. If you're installing a new garbage disposal, it's important to make sure that your electrical wiring can support the power draw of the unit.

Can you wire a garbage disposal directly to a switch? ›

Garbage disposals break down food washed into your sink to help prevent your pipes from clogging. If you don't want to reach under your sink and plug in the disposal each time you use it, you can wire a switch above your countertop that connects to the disposal's outlet.

How to power a garbage disposal? ›

Garbage disposals (sometimes called food disposers) can be connected to the electrical power supply in one of two ways. They are sometimes hardwired directly into a dedicated circuit, or they can be wired with an appliance cord that plugs into a wall outlet that is usually located inside the sink base cabinet.

How do you ground a garbage disposal wire? ›

Attach a copper wire securely to the disposer ground screw and attach other end of ground wire to a metal cold water pipe. Do not attach ground wire to a gas supply pipe. Use only UL Listed grounding clamp. If plastic pipe is used in your home, a qualified electrician should install a proper ground.

Does garbage disposal wire need to be in conduit? ›

Typically this wire is run in flexible conduit from the connection at the wall. Installers that don't know proper connection methods (aren't electricians) sometimes just hook the wire that comes through the wall directly to the disposer.

Is it better to hardwire or plug in? ›

Regarding safety, most professionals suggest hardwired systems are safer to operate than plug-in ones. There are several reasons why this is so. For instance, because they are directly wired into your home's electrical system, they do not rely on an extension cable to reach the outlet.

Does a garbage disposal need a power cord? ›

Cord or No Cord? Garbage disposals are available both with or without an electrical cord. While non-corded models are still electrically powered, they will need to be installed and hard-wired by an electrician or other knowledgeable appliance installation resource.

What is the code for garbage disposal wiring? ›

422.16(B)(1) Electrically Operated Kitchen Waste Disposers.

(2) The length of the cord shall not be less than 450 mm (18 in.) and not over 900 mm (36 in.). (3) Receptacles shall be located to avoid physical damage to the flexible cord. (4) The receptacle shall be accessible.

How many volts is a garbage disposal? ›

So, with a little bit of preparation and some spare time, you can be on your way to living the good life--the garbage disposal life. In order to install a garbage disposal, you have to have an available outlet that is protected by a 120 volt, 20 amp circuit breaker.

What size breaker for a garbage disposal? ›

Most garbage disposals use a 20-amp breaker to handle 15 amps of electricity. In some cases, the garbage disposal can require a 30-amp breaker.

Can a plumber wire a garbage disposal? ›

Even though it is not a difficult task for anyone who is handy with tools the job typically belongs to the plumber who could wire up a replacement disposal (assuming the previous disposal was properly wired).

What type of switch for garbage disposal? ›

The common type of switch for garbage disposals is an electrical wall switch, usually mounted on the wall near the sink area. Remember, electric wall switches can be dangerous and prone to electrical shocks. However, an increasingly popular and safe alternative is the push button switch.

Where should a garbage disposal switch be located? ›

Convenience and Accessibility: Placing the air switch near the sink provides more convenience and accessibility, allowing for easy and quick disposal operation while performing kitchen tasks.

Do all garbage disposals come with power cords? ›

Garbage disposals are available both with or without an electrical cord. While non-corded models are still electrically powered, they will need to be installed and hard-wired by an electrician or other knowledgeable appliance installation resource.

How do you attach a pipe to a garbage disposal? ›

To connect the drain, insert the gasket in the discharge outlet and then attach the discharge tube with the flange and bolts. Hang the disposal by aligning the three tabs with the mounting ring. Use the included wrench to turn and lock the tabs over the ridges. Connect the dishwasher drain.

How do you connect a drain hose to a garbage disposal? ›

Connect Hose to Garbage Disposal

Connect both ends of the hose with hose clamps (one on the air gap and one on the garbage disposal inlet nipple).

What colors do you wire a garbage disposal? ›

This involves connecting the black wire from the disposal to the black (hot) wire from the house, the white (neutral) disposal wire to the white home wire, and the green or bare (ground) wire to the home's ground wire. You can split direct wire to a dishwasher to handle garbage disposal as long as they are 120 VAC.

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