For many years, the standard 220-volt outlet was a three-pronged socket shared by all appliances needing that power level. For safety reasons, the outlet clothes dryers were changed by the National Electric Code to be a four-pronged outlet. All new construction and any remodeled construction must meet the new code for a laundry room. Both old and new dryers are easily converted to the best electrical power cord, sometimes called a pigtail, which fits the outlet.
A dryer with the new four-pronged pigtail does not fit a standard three-prong range outlet. If the dryer is bought new and you know that it requires the older style pigtail, request that it be converted at the store, which they do at no charge. If you are doing it at home, it requires a minimal amount of skill with tools, and a knowledge and experience with electrical repair.
Remove the back cover over the dryer’s electrical casing. Follow following the four-pronged pigtail where it is screwed into four locations inside the dryer. Remove them, but take note of which wire colors go where. Somewhere just above the center screw post where the white connected is a flat, copper strap with a hole in it. Place this strap over the center post using the hole in the strap before adding the new pigtail.
Place the connections for the pigtail’s white and green wires over the center screw post covering the copper strap. Screw the connectors firmly into place. Place the red and black connectors to each side on the screw posts and firmly attach them. It doesn't matter which of the colors go where. Place the cover back on, and the dryer now uses a standard, three-prong outlet. If you are using the dryer in the kitchen, be sure it exhausts properly preventing too much dust and moisture in the area.