Circuit Requirements for a Dryer
How can I wire a 4wire 240volt dryer cable? How to Identify The Wiring Connections for Your Electric Clothes Dryer.
Wiring an Electric Clothes Dryer
Electrical Question: How can I wire a 4wire 240Volt dryer cable?
- I recently acquired an old Maytag clothes dryer (Model # LDE 482, Serial # 222849 BF).
- The name plate on this unit states: “120/240VAC 3 wire 60Hz 5600 W”, which I have assumed means that the dryer was built for either a 120VAC or 240VAC supply.
- Because of the existing wiring (described below) I believe this dryer is currently wired for a 120VAC supply, via a 3-wire cable and connector.
- I need to convert this dryer for use with a 240VAC supply, via a new 4-wire cable and connector to a 4-socket 240VAC receptacle.
- Unlike your photo for a 3-wire hookup, wherein the red and black leads are connected to different terminals with the white wire connected to the middle terminal, the existing wiring in this dryer is currently terminated as follows: the black and red leads are co-connected to the same upper terminal; the 2 white leads are currently connected to the middle terminal; and a green lead is currently connected to the lower terminal.
- Also, a metal strip connects the middle (i.e white lead) terminal to a ground screw located just to the right of the middle terminal. Because the black and red leads are co-connected to the upper terminal, I believe this dryer is currently wired for only a 120VAC supply.
- So, to convert to a 240VAC supply, via a 4-wire cable, connector and receptacle, I assume the following is required:
- Remove the metal strip connecting the middle terminal to the adjacent grounding screw
- Reconnect the dryer-side green lead to the ground screw where the metal strip was previously connected prior to its removal
- Separate the black and red leads (currently connected to the same upper terminal), wiring one or the other to the lower terminal, where the green lead used to be connected.
- This should prepare the dryer for connection to a 240VAC supply via the new 4-wire cable, connecting: red-to-red; black-to-black; white-to-white; and green either to green, or to a grounding screw mounted on the rear of the metal cabinet.
Please advise your views ASAP. Thanks!
This electrical wiring question came from: John, a Homeowner from Parachute, Colorado
Thanks for your electrical wiring question John.
How to Wire a Dryer and Understand the Circuit Voltages
Application: Wiring Connections for an Electric Clothes Dryer.
Skill Level: Intermediate to Advanced – Best performed by a licensed electrician.
Tools Required: Basic Electricians Pouch Hand Tools and Voltage Tester or Continuity Tester.
Estimated Time: Depends on experience and level of problem solving skills.
Precaution: Testing live wires is dangerous and should be done by an experienced individual only. Additional testing using a continuity tester should only be made after the circuit has been identified and turned OFF and Tagged.
Understanding Equipment Labels and Circuit Voltage
When a dryer label states 120/240 this indicates that the device has both voltages present. In this case 240 volts is comprised of two lines consisting of 120 volts each and when testing Line-1 to Line-2 the voltage will be 240 volts, but when testing Line-1 to ground or neutral the reading will be 120 volts, and the same is true for line-2. Some clothes dryers have 120 volt controls, such as the timer, however the motor and heating elements are 240 volts.
This Dryer Question Specifically
- From what has been mentioned in the question, this clothes dryer may be a dual voltage dryer that can be wired for 120 volts or 240 volts.
- My concern here is that if this dryer truly is dual voltage then the nameplate should show two different watt ratings, one for 120 volt and another for 240 volt. If the dryer will require the same amount of watts at at 120 volts then it will require a 50 amp 120 volt circuit, which seems highly irregular and will cost a lot to run at that voltage.
- I would believe that the nameplate states both 120/24o because the control timer and buzzer is most likely 120 volts, and the heating elements and the motor are 240 volts, and this may be causing your confusion. If this is true, then the dryer should be wired for the standard 30 amp 240 volt connection and no alterations should be made to the internal wiring aside from the ground and neutral configurations, if allowed by the dryer.
- If this dryer is really dual voltage then the key to converting it would be to locate the wiring schematic or wiring diagram that should be attached to the dryer showing both voltage connection wiring assignments.
- The wiring assignments will involve moving internal wires of the terminals from one position to another to obtain the voltage that you have available.
- You must keep in mind that the voltage that you are wiring for must be the voltage that is at the receptacle that the dryer will be plugged into, and the cord wiring assignments must be configured correctly as well.
- If the wiring connections are not correct throughout then you risk a direct short which would trip the circuit breaker.
More about Wiring a Dryer Cord
- Wiring a Dryer
- See an electric dryer installation with a typical 220 Volt electric power cord wiring system. You may find yourself with either a 3-wire or 4-wire electric dryer, or a 3-wire or 4-wire outlet. Lets look a how the electric dryer is wired and what to do if your cord does not match the plug.
- Electrical Wire for the Home
- Complete listing of electrical wire types and parts used for home projects with electrical code information serves as selection guidelines.
Be Careful and Be Safe - Never Work on Energized Circuits!
Consult your Local Building Department about Permits and Inspections for all Electric Wiring Projects.
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