A modern dryer that uses 125 volts for its controls and 250 volts to power the heating element plugs into a NEMA 14-30R. A NEMA 14-30R, a 30-amp 125/250-volt 3-pole 4-wire grounded receptacle, has a 2 1/8 inch diameter face and mounts in a standard residential electrical box. The plug that fits into a 14-30R has two straight-blade hot prongs, one L-shaped neutral prong (the bottom prong) and a horseshoe-shaped ground prong (the top prong).
Things You'll Need
Turn off the NEMA 14-30R's circuit breaker. This circuit breaker usually uses a "Dryer" label.
Remove and discard the last 3/8 inch of the insulation on the wires that will connect to the NEMA 14-30R with wire strippers. Some wire sets use four insulated wires, and some wire sets use three insulated wires and one without a coating.
Grip the middle of the striped end of a wire with a pair of pliers and bend it into a hook. Repeat this on each wire.
Find the NEMA 14-30R's terminal identification letters above each terminal. A NEMA 14-30R uses the letters "G," "W," "X" and "Y."
Loosen the NEMA 14-30R's four terminal screws with a flat-head screwdriver.
Hook the ground wire on the NEMA 14-30R's "G" screw. Tighten the screw with the flat-head screwdriver. The ground wire uses green insulation, green and yellow striped insulation or no insulation at all.
Hook the neutral wire over the NEMA 14-30R's "W" screw. Tighten the screw. Neutral wires have white colored insulation.
Hook the hot wire with black insulation on the NEMA 14-30R's "X" screw. Tighten the screw. Choose either black wire if the wire set contains two wires with black insulation.
Hook the last wire on the NEMA 14-30R's "Y" screw. Tighten the screw. The remaining wire, the second hot wire, has either a red or black covering.