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Did your old garbage disposal finally break down? Installing a new garbage disposal isn’t difficult as long as you have the right tools and materials. Make sure you have the right type of disposal for your plumbing, then follow these instructions to have your disposal working in no time.
- If you have children who will be using the disposal, consider getting a batch feed disposal rather than a continuous feed disposal. Batch feed disposals, which are a bit more expensive, require the use of a stopper prior to operation, which can be safer in households with kids. Continuous feed disposals start running when you flip a switch and keep running when you switch it off. If someone drops a utensil down the drain or sticks their hand inside, this can be a dangerous situation.  X Trustworthy Source Consumer Reports Nonprofit organization dedicated to consumer advocacy and product testing Go to source
- Choose a motor that’s right for your household. Models with lower horsepower, usually about 1/3, are suitable for small households with a small amount of food waste. Models with 1/2 horsepower are better for larger households with more food waste.  X Trustworthy Source Consumer Reports Nonprofit organization dedicated to consumer advocacy and product testing Go to source
- Consider the features you want the disposal to have. For a higher price, you can buy a disposal made to function more quietly, one made from stainless steel, or one that connects to your dishwasher.
- If your plumbing is connected to a septic tank, you need to buy a disposal made especially for septic tanks.
- A screwdriver
- A disposer wrench
- A hacksaw
- Water pump pliers
- Plumber’s putty
- Electrical cord
- Safety supplies, including goggles and a dust mask
- Working from beneath the sink, use a screwdriver to screw the mounting ring tightly against the sink. It helps to alternate sides, screwing one screw and switching to the other, so that the mounting ring tightens evenly.
- Some of the plumber’s putty will have squeezed out around the flange. Use a knife to trim it away.
About This Article
To install a new garbage disposal, start by removing the old disposal and taking apart the rest of the mounting assembly. Then, attach the wires in your new disposal according to the manufacturer’s instructions, insert the drain flange, and screw the disposal into the mounting ring. Afterwards, connect the disposal to the sink trap and the dishwasher discharge tube. Finally, run water into the sink and turn on the disposal to make sure that it works. To learn more, including how to figure out what kind of garbage disposal you need, scroll down.
This garbage disposer must be connected to a grounded, metal, permanent wiring system; or an equipment-grounding conductor must be run with the circuit conductors and connected to the equipment-grounding terminal or lead on the garbage disposer.
Connect garbage disposal into properly grounded outlet (see hardwiring instructions below).
- Outlet must be 110-120 volt, 60 Hz AC current only.
- If a properly grounded 110-120 volt, 60Hz AC outlet is not available, have a proper outlet installed by a qualified electrician.
2. Above Deck Requirements
Outlet must be controlled by a dedicated wall switch with a marked “off” position, and have a proper switch installed by a certified electrician.
- Wall switches are generally located on the wall behind the sink
Switch must be mounted within sight of sink opening or garbage disposal
3. Hardwiring The Garbage Disposal
Turn power off at circuit breaker or fuse box.
1. Remove the metal plate on the bottom of the garbage disposal.
2. Using wire cutters, cut the white neutral and black hot wires close to the connectors and cut the green ground wire just before the groove where the cord enters the garbage disposal.
3. Pull the electrical cord out of the housing.
4. Install cable connector (not included) into the access hole and secure it by tightening the nut.
5. From wall, insert power supply cable through the connector and tighten connector.
6. Connect internal disposal lead wires to coordinating wire lead from electrical source. Connect white to white, black to black or red, and green ground wire to the ground lead with wire nuts (not included).
7. Push wires into garbage disposal and replace the metal bottom plate (Do not displace plastic shield with label).
Still Not Finding What You’re Looking For?
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.
When hardwired, the disposal is connected to a switch that is installed in an electrical box either in the sink base cabinet or on a wall near the sink. If the switch is near the sink, there’s usually a second box, serving as a junction box, inside the cabinet. Any exposed wiring inside the cabinet should be protected by flexible metal conduit (BX cable, or “Greenfield”).
With the plug-in configuration, the disposal cord plugs into an outlet (receptacle) located inside the sink cabinet. The outlet is controlled by a wall switch, which is usually located on the wall near the sink. The outlet is often wired as a split receptacle so that only one half of the outlet is controlled by the switch; the other half is always powered and can be used for another appliance, such as a water filter or dishwasher.
Cords are not sold with disposals and must be purchased separately. Be sure to use a grounded cord with the appropriate voltage and amperage ratings for your garbage disposal. It’s usually easier to connect the cord to the disposal before mounting the disposal under the sink, but you can also complete the wiring after the unit is mounted.
Garbage Disposal is an amazing appliance that helps to break down food washed into your sink drain and prevent the pipes from getting clogged. So, it is important to install the garbage disposal switch near the countertop so that you can switch it on easily whenever required.
Installing a garbage disposal switch is a complicated process that requires prior knowledge and experience working with the electrical components. So, before starting the installation process, make sure you have proper knowledge, skills, and tools to complete the installation. Otherwise, for your safety, call an electrician.
Basic Information About Garbage Disposal Wiring
After running the wires from the garbage disposal to the switch area, you will be left with a box with wires coming out of it and no switch to plugin your garbage disposal. Installing a garbage disposal switch involves different wirings and outlets. Let’s make you familiar with the wires before starting the installation process.
- Nowadays, electrical installations in homes have a dedicated circuit for your garbage disposal and the dishwasher and as they are generally installed together, the outlet is comprised of two parts, when divided, the top outlet is controlled by the switch, where your garbage disposal will be installed, and the bottom outlet remain always on which you can connect with your dishwasher.
- The black wire is the hot wire, which goes through the circuit breaker, and the output of the circuit breaker is divided into two branches, one gets connected to the garbage disposal and the other one is connected to the outlet.
- The neutral wire is a white wire which directly goes to the outlet.
- The green wire is the ground wire, both outlet and garbage disposal should have ground wire connected.
- The red wire runs from garbage disposal to the outlet.
Tools Required to Install a Garbage Disposal Switch
- Outlet box extender
- Needle nose pliers
- Wire stripper
- Electrical tape
Steps to Install a Garbage Disposal Switch
Step 1 – Firstly, pull out all the wires and test the power to make sure there is not any current running. You can use a voltage tester to test it. If it lights up the power is still there and if not, then you are good to go.
Step 2 -We have to add the outlet box extender. We have to put it in the hole bypassing all the wires through it. This box allows you to mount your outlets on the wall and helps to protect the wires from the inside.
Step 3 – Strip the ground wire with the help of a wire stripper, turn the wire around the ground screw with the help of a needle-nose plier and tighten the ground screw with a screwdriver.
Step 4 – On the outlet, the dark-colored screw is for dark wires (black wire), and the light-colored screws are for light wire(white wire).
On the top part of the outlet, you have to connect the garbage disposals hot and neutral wires, and on the bottom part, you have to connect the hot wire and neutral wire of the dishwasher.
Strip the black wire and white wires to about three-quarter inches, turn it with needle-nose pliers, insert it in their respective screws and tighten the screws.
Wiring of your outlet is complete, now secure the wires with the help of electrical tape and screw the outlet on the outlet box.
Step 5 – Now, we will install the switch for the garbage disposal.
Wrap the green ground wire around the ground nut and tighten the screws. On the switch, there will be two copper screws. On the top one, you have to connect the red wire which is coming from your garbage disposal. Insert the wire with the help on pliers and tighten the screws. Similarly, insert the black wire in the bottom screw and tighten the screw with the screwdriver.
Install the switch on the outlet box. Make sure it is facing in the right direction. Generally, to identify the direction, you can find a small gold metal plate on the top of the switch.
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I took out my kitchen and took some photos of the “old” kitchen’s garbage disposal wiring:
As you can see, it has 2 black lines connected but only one white line connected, while one is capped off.
I know the main purpose is to use the switch to control one of the outlets BUT isn’t this is the right way to wire it?
I am a bit confused about the two setups and differences.
The thing is I tried to follow the diagram above and couldn’t get the switch to control the outlet and it was ALWAYS ON.
2 Answers 2
There’s not quite enough information here to answer your question. But we can try after making a couple assumptions.
From what I gather the picture is of the outlet box and the garbage disposal plugs into the top outlet. Presumably the cable exiting at the top of this box is from the supply (or else the disposal would never run). The rest of your question implies that there is a switch box as well so I assume the cable exiting to the right leads to a 2-pole switch? You’re trying to understand how to wire this switch such that the top outlet in the outlet box can be switched.
If my understanding of your question is correct then the switch is on a switch loop and the diagram you have posted does not apply. Instead wire as follows. Connect supply black to switch loop black. Re-identify the switch loop white cable as black and connect it to upper outlet hot. Leave the supply white connected to neutral outlet. With the hot tab jumper in place this will get you a switched outlet (both receptacles).
If you wish to switch only the top receptacle break the hot tab on the receptacle and connect supply black to the bottom hot side of the outlet. Use a pigtail since supply black is now feeding the switch loop and the lower receptacle.
We moved into a new house last week. I was greeted with a faulty garbage disposal switch in the kitchen. The switch works intermittently depending on how hard it’s pressed.
The second issue was the GFCI duplex receptacle on the right of the switch, was not working at all. A reset did nothing.
So I figured I’d replace the GFCI duplex with a new one from the hardware store. After installing that, the new GFCI would not turn on either, despite 120v power to the line terminals (as tested with my meter).
So I disconnected the load wires (pictured on the bottom), and the GFCI started working. The garbage switch continued to work (albeit just as flakey as before). Obviously the downstream receptacle (on the left) that was connected to load (on the right), wont work if it’s disconnected.
So I’m wondering should I just replace the switch combo and wire it the same? Or maybe the thing is not wired correctly to begin with. Unfortunately I’m unable to ask anyone about what occurred here.
For reference this is a 2-gang box with 4 wires coming in (actually 5 if you include the ground on the left).
As they say though, a picture is worth a thousand words 🙂 Any help would be great!
Electrical Wiring Diagram for a Garbage Disposal and Dishwasher
How to Install and Wire a Garbage Disposal
These wiring diagrams show typical connections.
The diagram above shows the power entering into the circuit at the switch box location, then sending one power line for the dishwasher and a switched leg for the garbage disposal.
The diagram below shows the power entering the circuit at the grounded outlet box location, then sending power up to the switch and a switched leg back down to the outlet.
Notice that these outlets have the tab removed from the “hot” side or Brass side of the outlet which allows the top half of the plug to be controlled only from the switch while the bottom end of the outlet remains “hot” all the time. This is shown in the pictures below.
Disposal Wiring Diagram #1
Disposal Wiring Diagram #2
The Process for Wiring a Switched Garbage Disposal with an Optional Dishwasher
Instruction Manual for a Garbage Disposal
Identifying the Wires of a Disposal Cord
George, from Austin, Texas asks:
I want to connect a power source to a garbage disposal and however, the power source cable does not have a white cable as instructions state, instead has two black cables, one soft and other rugged or with lines. Which wire represents the white? Any help is greatly appreciated.
Great website – Very complete and helpful!
Disposal Cords often have the same color insulation for all of the wires so it ca be very difficult to tell which wire is which, however there is one way to know which wire is for the hot and which is the neutral:
The smooth wire is for the hot or connects to the Black wire of the disposal.
The wire with lines is used for the neutral and connects to the White wire of the disposal.
The center wire is typically the ground and in most cases the ground wire, and with some cords the ground wire has green insulation.
Be sure to use a two screw cord connector when attaching the cord to the disposal.
Kitchen Disposal Wiring
You saved me a lot of headache!
Your Welcome Steve!
I’m glad this helped you with your kitchen disposal wiring.
Disposal Wiring Made Easy
Excellent article and diagram Dave.
If I didn’t know better I would think I was an electrician.
Well thank you very much, Nelson!
Many Handymen and Handy women are Fine Basic Electricians with a great deal of potential.
I’m glad this disposal wiring diagram was helpful for you.
More about Wiring a Disposal Switch
Garbage Disposal Electrical Wiring Diagram
How to Wire a Switch and Outlet for a Garbage Disposal: Disposal wiring diagrams with pictures for wiring the outlet.
Kitchen Disposal Switch Wiring
How to Electrical Wiring for a Kitchen Disposal Switch
Electrical Wall Switch Variations
How to Wire Switches for a Light and Garbage Disposal – Either Leviton or Lutron will have a switch that will take care of your application. Another option would be to purchase an Insinkerator switch package.
Learn more about wiring a disposal switch
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