Using a used electric dryer power cord as a replacement can work, as long as the old power cord conforms to current safety codes and there is nothing wrong with the cord itself. But you must replace the cord if it shows any signs of wear, so check it carefully for any fraying, kinks or other signs of damage.

You might be unable to reuse the electric old dryer power cord if you’re faced with a new power outlet. If you move to a new home, you may find that the outlet for the dryer may not fit your old cord. In this case, you will need to purchase a new cord. 

A 3-prong dryer cord was the standard prior to 2000, at which point the National Electrical Code required 4-prong dryer outlets in all new home construction. Existing homes may still use 3-prong outlets.

The switch to a 4-prong outlet was due to a flaw in the 3-prong outlet design. In a 3-prong outlet, the ground and neutral wires are contained in the same prong. This has the potential to allow a current to find its way onto the ground wire. The 4-prong dryer cord is comprised of two hot wires, a neutral wire and a ground wire. This creates a separate return path for unused current. Dryer cords are usually a maximum of six feet long as the code requires that an outlet be within six feet of the connected appliance. 

• Before you begin, turn off the power to the dryer at the circut breaker. 

• Almost all manufacturers sell dryers without a cord attached, preferring to let you choose the cord you need to match your prong outlet. Check to see if the cord will be installed for you after your purchase.

• When removing connection screws, a magnetic nut driver can save you time by preventing screws from falling inside the machine.

• Before you begin, turn off the power to the dryer and unplug the unit.
• Open the access panel where the cord enters the back of the dryer.
• Use pieces of masking tape to label which colored wire attaches to each terminal. The wires are typically color-coded with a black wire on one end, a white wire in the middle, and a red wire on the other end.

• Loosen the connection screws holding the wires in place.
• Disconnect the ground wire or strap that connects the center terminal to the case.
• Use pliers to hold the strain relief bracket in place while loosening the bracket's screws.
• Remove the old cord.

Tip: When replacement cord wires are color-coded, simply match the colors of the new cord’s wires to those on the terminal block. Consult the dryer wiring diagram in the user manual.

3-prong cord

• Attach the middle or groundwire to the center terminal, one of the outer wires to the right terminal, and the other outer wire to the left terminal.
• Attach the grounding strap or wire that runs from the center terminal to the dryer case.

4-prong cord

• Attach the white wire to the center terminal, the red wire to the right terminal with the red wire installed, and the black wire to the left terminal with the black wire installed.
• Attach the green wire to the green grounding screw or dryer case.
• Remove the masking tape labels.

Consider the following when shopping for new appliances:

• 3-prong plugs are used for homes build before the year 2000. 
• 4-prong plugs are used for homes built after the year 2000. 

When you add professional installation to your new appliance purchase from The Home Depot, a compatible cord is required. The delivery agent carries both types of cords to make sure your home is covered.

When you purchase a new appliance from The Home Depot without professional installation, a 4-prong cord is sent by default. If your home is equipped with a 3-prong outlet, you will need to purchase a 3-prong cord or connector adapter separately. 

• Fit the strain relief bracket into the cord access hole and evenly tighten both bracket screws firmly onto the cord. This is important as the bracket protects the connections and helps avoid a possible short if the cord is yanked.
• Replace the access panel on the back of the dryer.

• Double check that the power to the dryer outlet is turned off.
• Plug the dryer into the outlet.
• Turn on the power to the outlet and test your dryer.