If you have a 4-prong dryer outlet and only three wires, it means you have an older wiring setup that does not include a dedicated ground wire. In this situation, you have a couple of options:
Upgrade the wiring: The best and safest option is to upgrade the wiring to meet current electrical code standards. This typically involves running a new 4-wire circuit from the electrical panel to the dryer outlet. It requires the expertise of a licensed electrician to ensure proper installation and compliance with local regulations.
Use a 3-prong cord: If you don't want to upgrade the wiring, you can replace the 4-prong dryer cord with a 3-prong cord that matches your existing outlet. Keep in mind that this option is not recommended as it does not provide the same level of safety as a dedicated ground wire. However, if you choose to proceed, here's how to wire a 3-prong cord to a 4-prong outlet:
a. Unplug the dryer from the power source. b. Locate the terminal block on the back of the dryer. It is typically covered by a metal plate held in place by screws. c. Remove the plate to access the terminal block. d. Identify the three wires: black (hot), white (neutral), and green or bare copper (ground). e. Connect the black wire to the terminal labeled "L1" or "X". f. Connect the white wire to the terminal labeled "N" or "Neutral". g. Connect the green or bare copper wire to the metal chassis of the dryer using a grounding screw or a grounding strap if provided. h. Replace the metal plate covering the terminal block. i. Plug the dryer back into the power source.
Please note that while this method may allow your dryer to operate, it is not up to current electrical code requirements and may present safety risks. Upgrading the wiring to include a dedicated ground wire is the recommended approach for long-term safety and compliance.