Changing a Dryer Cord

As explained elsewhere on our site, an electric dryer uses a 120/240 volt circuit to power it. That requires a special appliance cord or 'pig tail'. Originally dryer cords only had 3 wires with 3 corresponding prongs at the plug. Later a 4-wire cord which had a dedicated ground wire was introduced for use in mobile homes. That 4-wire system has become standard in most new home construction.

If you have a dryer with an older 3-wire cord, it is usually possible to install a new 4-wire cord onto it if your wall outlet is also a 4-slot type or vise versa. It is usually best to change the cord rather than downgrade the outlet to the older 3-wire outlet type although that may be an option as well (check local building and electrical codes). It is not usually possible to upgrade a 3-slot wall outlet to the newer 4-slot outlet without also changing the wiring from the fuse box to the outlet.

The above image shows a 3-wire cord connected to the dryer's main terminal block. The neutral wire of the cord is connected to the center terminal of the block which is in turn connected to the cabinet via a 'grounding strap'. Each of the two remaining wires of the cord is connected to one of the outside terminals.

The above image shows a 4-wire cord connection. Notice the grounding strap has been disconnected from the main power terminal block. A separate green ground wire from the cord is attached to a green colored screw on the cabinet, effectively grounding the cabinet. The white wire of the cord is connected to the center terminal of the terminal block, the red wire to one of the outside terminals and the black wire to the other outside terminal. It does not usually matter which side terminal the red and black wires from the cord attach to as long as they are not connected to the same one, or the center one the white from the cord attaches to. Trying to keep them color coordinated with the dryer's wiring would be a good practice, though not absolutely critical.

There have been several different types of dryer main terminal blocks used by the various manufacturers over the years. The one on your dryer may differ in design from the one shown in the illustrations above. They all serve the same purpose though. On newer dryer models you may however need to order the proper replacement dryer cord which is specifically designed for your particular dryer model due to the way it might secure to the dryer cabinet.

Always make sure the cord is securely fastened to the cabinet in some way to prevent it from being pulled out by mistake, which could lead to shorting and the possibility of a shock hazard. When dealing with laundry equipment which are in close proximity to water, electrocution is a major risk and precautions should not be taken lightly!