Larger appliances, such as clothes washers and driers, freezers, ovens, and some electrical heaters, require a 220-volt electrical outlet for adequate power. Although these outlets are designed to withstand more stress from larger power cables and prongs, they do wear down over time and must be replaced. There are two types of 220-volt outlets: Those that use four wires and those that use three. It's best to remove the old outlet first, then purchase a replacement that uses the same number of wires in your home's walls for ease of installation.
Turn off power to your 220-volt outlet circuit at the circuit breaker. Close the door to your circuit breaker box and install a lock onto the door, if your breaker box has a lock lug, to prevent others from accessing the switches while you're working on the outlet.
Test the outlet to ensure the correct switch was turned off. This may be done with a digital multimeter set to measure 220 volts AC, or a lighted test probe designed to measure up to 240 volts AC. To use a multimeter, turn it on to measure 220-volts AC and insert the black-handled metal test probe into the left (negative) outlet slot, and insert the red-handled metal test probe into the right (positive) outlet slot. If the meter reads zero volts, it's safe to work with the outlet. A lighted test probe lights up when there is power. Simply connect the alligator clip to the metal mounting screw of the outlet and insert the sharp probe tip into the right (positive) slot of the outlet. If the light doesn't activate, it's safe to work with your outlet.
Remove the exterior mounting screws of the 220-volt outlet casing. Gently pull the outer cover off of the outlet to reveal the interior.
Remove the interior mounting screws of your outlet that attach the metal outlet frame to the wall.
Pull the outlet out from the wall gently and slowly, letting the wires stretch as you pull. Be careful not to pull the outlet too rapidly--you don't want the wire ends to break off of the mounting screw posts.
Observe the orientation of the outlet and how the wires are connected to it. If necessary, draw a basic diagram on a piece of paper showing which wire colors mount to each of the three or four screws of your outlet. Then use a screwdriver to loosen all the wire mounting screws until fully unscrewed. Use a pair of needle-nosed pliers to disconnect the wire ends from the screw posts.
Orient the new outlet in the same way the old one appeared, and connect the wires from the wall to each of the screws. Double-check your wire colors to be sure they are connected to the correct screws. Looking at the new outlet, each screw will be colored, or the name of each screw post will be molded into the plastic near each screw. Four-wire outlets connect as follows: Black goes to negative, red goes to positive, white goes to common, and green goes to ground. Three-wire outlets connect as follows: Black goes to negative, red or white goes to positive, and green goes to ground.
Tighten all of the screws firmly onto the wire ends with a screwdriver, then gently fold the wires back into the wall much the same as they were folded in the wall with the old outlet. Press the new outlet mounting "rabbit ears" firmly against the wall or metal chassis so the mounting holes line up. Insert the mounting screws and tighten fully. Place the outer cover over the outlet and screw it on.
Turn on the power, at your circuit breaker, to your newly installed outlet and test it with your multimeter or lighted test probe to see if power is present. Use the same multimeter settings and multimeter/light probe procedure used in Step 2. If using a multimeter, the reading should show between 235 and 240 volts.