How to Wire a Dishwasher

It was at the 1893 World's Fair that a small, wealthy woman from Shelbyville, Illinois won the highest award for her invention. Her name was Josephine Cochrane and her invention was the automatic dishwasher. The rest, as they say, is history.



The dishwasher is one of modern society's most beloved appliances. No longer do people have to say, "I don't do dishes." While truly ingenious in their design, dishwashers are really quite simple to install. Here is how to wire a dishwasher.

Difficulty: Moderate

Instructions

Things You'll Need:

• Screwdrivers
• Wire strippers
• Needlenose pliers
• Voltage tester
• Wire connectors
• Electrical tape
• 20-amp breaker
• 12-2 NM cable
• Electrical wire connector
• Electrical wire stripper

1. The first thing you will have to realize is that your dishwasher will need a dedicated circuit. Meaning, it has to have its own power supply and not one that is being shared with other devices. If you are replacing an existing dishwasher, then you already have one there. But if you are installing your first dishwasher, then you will have to run a line of 12-2 NM cable from the electrical panel to where you are installing the dishwasher. At the panel, you will need a 20-amp breaker specifically for the dishwasher.
   
   URGENT -- It does not matter if you are replacing an existing dishwasher or installing an original, the circuit breaker needs to be OFF before you handle any wires. Use the voltage tester to ensure the circuit is OFF. Plus, turn off the water supply to the existing machine before you remove it!

2. You should leave a coil of about 2 to 3 feet of NM cable behind the dishwasher so you can easily pull it back out if maintenance or troubleshooting ever needs to be performed on it.

3. On the backside of the dishwasher, near the base, you should see a metal junction box. Remove the screw holding the cover in place and pull off the cover.

4. Inside, you should see one black wire, one white wire and either a green ground wire or a green ground screw. Use your needlenose pliers and remove the knockout on the side of the junction box.

5. Insert your electrical wire connector into the knockout hole and secure it with the lock nut. Be sure to keep the clamp screws easily accessible for your screwdriver. Loosen the clamp screws but do not remove them entirely.

6. Use the electrical wire stripper to cut and remove the outer sheath of the NM cable. About 6 inches should suffice. Next, use the wire strippers to remove about 3/4 inches of the insulation from the exposed wires.

7. Slide the wires through the electrical wire connector and into the junction box. Tighten the clamp screws on the connector to hold the cable in place. Be sure the clamp is tightening over the sheathed section of the cable, NOT the exposed wire.

8. Connect the ground wire from the NM cable to either the ground wire or ground screw on the dishwasher. If it is wire to wire, use a wire connector to secure the wires.

9. Twist the white wires together and secure them with a wire connector. Then, do the same for the two black wires. For a bit of extra safety, tightly wrap a strip of electrical tape around each wire connector at the point where it meets the wire.

10. Replace the junction box cover. Connect the hoses for the water feed and drainage and push the dishwasher back into position, being careful not to crimp or cut the coil of slack NM cable behind the machine. Once it is in position, secure it as per the manufacturer's instructions. Turn the water supply back on.

11. Open up the dishwasher and make sure there is nothing inside the washing compartment. Then, turn the circuit breaker back on and try a test run. That's it!