For the most part, you don't need a new power supply cord when you're replacing an old dryer with a new one. Since most new dryers don't come with a power cord, the appliance salesman might recommend that you purchase a new one. However, so long as your existing power cord is in good condition and shows no sign of wear, then it should work just fine with your new dryer.
If you're switching out or upgrading your dryer for a new one, you don't necessarily need to purchase a new cord, provided that there's nothing wrong with the old one and it conforms to the most current electrical safety codes. In most cases, the dryer installer can detach the old cord from your existing dryer and reattach it to the new dryer without issue. In certain cases, an appliance salesman might tell you that it's absolutely necessary that you purchase a new power cord, but this isn't always the case. It's possible that he might try to squeeze more money from you. Use your discretion. Even if you think you need a new power cord, don't be afraid to shop around. It's possible to save a few dollars by buying the cord separately from another appliance retailer.
Replace Frayed Power Cord
Only reuse an old power cord for a new dryer when there's nothing wrong with it. Inspect it to make sure that no wires are visible and that the cord hasn't frayed or shows obvious signs of wear. If there are any problems with the cord, buy a new one. Most appliance stores sell power cords for dryers.
Update Three-Prong Power Cord
Sometimes you need to upgrade a dryer's power cord from a three-prong to a four-prong plug. When you relocate to a different residence, and purchase a new dryer you might discover that the old power cord doesn't fit the power receptacle in your new home. More recent safety measures have been instituted for larger 240-volt electrical appliances, including dryers, that provide for a fourth prong on a power cord that's tied to a new forth wire. The additional prong grounds the appliance as an added safety feature to guard against electrical shocks. If you go to plug your dryer into a four-pronged electrical outlet and the power cord is missing the fourth prong, purchase a new cord.
Importance of Grounding a Dryer
You must properly ground a dryer. Grounding reduces the risk of electrical shock by redirecting an electrical current away from the appliance in the event of an electricity surge. If you attempt to plug a new power cord into an outlet that hasn't been grounded, you risk short circuiting your electrical system and possibly the dryer if an electrical breakdown occurs. Only plug your dryer's new power cord into an outlet that meets local codes and ordinances. Don't risk using an old power cord that doesn't meet current safety standards.