How to Wire a 30 Amp Dryer Circuit

Electrical wiring is not exceptionally difficult. However, it takes on another level of difficulty when the step is made from 110/120 volt to 220/240 volt circuits. Most clothes dryers require a 30 amp 220/240 volt circuit to operate. A 220/240 volt circuit is comprised of two 110/120 volt circuits that share a common ground. Wiring in a 30 amp clothes dryer requires beginning the process in an open circuit box where physical harm can occur in the blink of an eye if proper care is not taken.

• 1

  Go to the main circuit box that you will use to provide the power for the clothes dryer. Open the door and either pull the main fuses or turn off the main circuit breakers. These are large fuses or breakers that are usually at the very top of the box. Fuses will have a handle that you can safely grip to pull the fuses from the box. The breakers will be much larger than any other switches in the box.

• 2

  Use a screwdriver or wrench to remove the screws or bolts that hold the cover of the circuit box in place. When the cover is off, replace the screws part of the way into their places to store them until you need them later. Set the circuit box cover aside. You should see two rows of breakers running down the middle of the circuit box. The black wires coming out of the breakers are the hot wires. The white wires that are connected to the metal plates along the sides and bottom are the ground wires.

• 3

  Locate the next open socket for a breaker to be inserted inside the panel. These panels are generally filled from top to bottom, but not always. Any open socket large enough to accommodate the 30 amp 220/240 volt breaker will be acceptable. Breakers that carry 220/240 volts will be twice as thick as the 110/120 volt breakers. They are designed to plug both of the 110/120 volt circuits inside the box at the same time. Instead of one black wire attaching to them, they will have two.

• 4

  Insert one end of the new 220/240 volt cable with three wires into an opening in the box at either the top, side, or bottom in the box. This may require you to punch out a piece of metal that covers the new opening. For a new opening, you will need a clamp that fits inside the hole and can be tightened around the wire to hold it into place. If you can use an existing opening, you will need to loosen this clamp to slip the wire through it.

• 5

  Separate the three wires by using a wire stripper to remove the outer insulation and exposing the two black and one white wires. Strip each wire back about 1/2 inch. Insert the two black wires into the breaker and tighten the screws with a screwdriver. The breaker will then plug into the box. Make sure it clicks into place. Attach the ground wire to an open screw on the ground plate. If the wire is 10/4 instead of 10/3, it will have 4 wires. The last wire is a second ground and will attach to the same ground plate as the third wire. Tighten the clamp where the wire exits the box to complete the wiring inside the box. Replace the cover on the circuit box.

• 6

  Run the wire from the box to the location of the dryer plug. The dryer plug will have a cover that will come off when the screw is removed that holds it in place. Under the cover will be three screws. Two will be located near the top and one at the bottom. Strip the insulation from the three wires about 1/2 inch. Insert each black wire under one of the two top screws. The white wire will go under the bottom screw. If you are dealing with a 4 wire configuration, consult the instructions for the specific dryer plug that you are using for the connection of the fourth wire. Using the screws that come with the dryer plug, attach it to the wall near where the dryer will sit. Replace the cover and tighten it into place.

• 7

  Turn the power back on at the circuit box by replacing the main fuses or flipping the main breakers on. Make sure that the breaker leading to the dryer is on. Label it on the door of breaker panel. Turn on the dryer and make sure that it heats up and runs to complete the job.