A dryer adapter connects the wiring inside the dryer to the wall outlet. These adapters consist of a cord that joins the leads on the dryer and ends at the wall outlet. Since 2000, the National Electrical Outlet has required new homes to have four-prong dryer outlets.
Moving from a house with a three-prong outlet to one with a four-prong outlet does not mean having to buy a new dryer, thanks to the adapter. Simply changing to a four-prong cord allows the owner to keep the dryer. Even though code requires four-prong outlets in new homes, it is acceptable to change to a three-prong adapter when moving into a house that already had a three-prong outlet before the code change.