Wire an Electric Dryer

Modern appliances require 4 conductor cord sets (separate conductors or wires for line 1, line 2, ground and neutral). Generally, this setup is safer, because the current-carrying neutral is not connected to the dryer case. However, it is useless if the wall receptacle does not have a separate ground slot. In that case, you'll have to do the very simple procedure of converting a 4-wire dryer to a 3-wire setup. Conversion of these appliances in the U.S. is prohibited by the NEC (National Electric Code). The receptacle and wiring should be modernized to a 4 conductor arrangement instead.

Steps

  1. Verify the electrical requirements of the dryer. Most sold for use in the U.S. and Canada require a 240 volt / 30 amp supply.
  2. Check that any existing dryer receptacle has this same rating and note number of slots (either 3 or 4 slots).
  3. Obtain a cord set with the same electrical rating and number of slots as the receptacle. If purchasing a cord set by matching the electrical rating of the receptacle; remembering the slot pattern will not matter, as they are standardized. Most hardware stores and nearly all home supply centers offer cord sets for electric ranges and dryers with a choice of either 3 or 4 conductors for under $25 or so. These cord sets may look similar, but are not interchangeable due to different electrical ratings. Dryer cord sets are 240V/30A and range cord sets are 240V/40A for use in the U.S. & Canada.
  4. Connect the cord set to the terminal block at the rear of the dryer. The cord set selected should have only 3 wires (line 1, line 2 and neutral; no ground wire). The center wire of this cable is the neutral wire and the outer wires are the "hot" line 1 and line 2 wires. These hot wires connect to the outer 2 connections the power terminal block of the dryer, does not matter which is which as long as one hot is connected to each of the outer terminal connectors.
  5. Notice that the center wire (neutral wire) of the cord set goes to the center connector. Since in this case the neutral serves as a neutral and a ground connection, a jumper conductor (ground strap) is also connected to the center terminal and to the frame of the dryer. A green wire could also be used to connect the center connector to the frame of the dryer.
  6. Understand color coding of conductors in the cord set. If the dryer cord does have colored wires, white is the neutral wire to the center connector, the red and black wires are the hot line 1 and line 2 wires which connect to the 2 outer connections of the dryer terminal block. Don't forget the ground strap or green wire jumper from the center connector to the dryer frame.

Tips

  • Securely tighten the wires under the terminals.

Warnings

  • Always make sure any electrical appliance is UNPLUGGED before working on it!
  • While an acceptable practice some years ago, as stated in the opening, this practice has been banned in the U.S. by the NEC. The only safe, legal way to connect 4 wire ranges and dryers is with a 4 wire cord set to a 4 wire receptacle fed by a four wire circuit. Adapters and 3 wire cord sets used to connect these appliances are not permitted. A new, four wire circuit and receptacle is the only safe, legal and accepted method to connect these appliances.
  • It is illegal in Canada to work on any 240V circuit unless you are a licensed electrician. If you start a fire, your insurance can be voided.
  • These instructions only apply to a centre-tapped 120/240V supply as found in the US and Canada; do NOT use them in other configurations. In particular, using neutral as ground will prevent ELCBs (earth leakage circuit breakers) or RCDs (residual current devices) from operating and hence present an electrocution hazard.

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