A dryer can be connected to a dryer outlet using either a 3-prong or 4-prong dryer cord, which should be wired according to the internal color coding. The cord's number of prongs and wires must match the number of prongs on the dryer outlet.
The dryer cord must be unplugged during installation and power to the dryer outlet turned off. A 3-prong dryer cord contains three individual wires, colored coded black, red and white. A 4-prong dryer cord includes a fourth wire, colored green, which acts as a ground. On the back of the dryer is an access panel; remove this using either an adjustable wrench or screwdriver. Under this panel are three terminals. Thread the dryer cord into this access compartment through the cord access hole.
Connect the white neutral wire of the dryer cord to the center terminal, using either a screwdriver or adjustable wrench to secure the connection. The outer terminals receive the hot legs, or red and black wires. Best practice is to connect the red wire to the right terminal and the black wire to the left terminal. If installing a 4-prong wire, connect the green wire to the green grounding screw or the dryer's case. For a 3-prong wire installation, bond the green grounding screw or dryer's case to the center neutral terminal using a ground strap.
Once all connections are secure, affix the cord to the dryer with the strain relief bracket and close the access panel cover. With the dryer outlet power still off, plug the dryer cord into the outlet. After turning the power on, test the dryer.