How to Replace an Electrical Outlet
If an outlet (commonly called a receptacle) no longer holds a plug snugly, it should be replaced. The procedure for replacing a duplex (two-outlet) wall receptacle is similar to that of replacing a switch. The only difference is that, depending on where the receptacle is located in the wiring scheme of your house, it may have more wires attached to it than you find attached to a light switch.
Look closely at the terminal screws of the new duplex receptacle. On each side of the receptacle is a pair of terminal screws. The upper screw is connected to the upper outlet, and the lower screw services the lower outlet. A thin, metal break-off tab connects these screws. This tab enables you to attach a single wire to either screw and feed electricity to both outlets of the receptacle. If the tab is broken off, you can connect the upper and lower outlets to separate wires and control them independently.
If the receptacle is wired to the end of a series of receptacles, it usually has only two wires, and possibly a third ground wire. If it isn't the last receptacle, two additional wires may be connected to it in order to carry current to the next receptacle. Just rewire the new receptacle the same way the old one was wired.
You may also wire the receptacle so that a switch controls the upper outlet and the lower outlet is on, or hot, all the time. In this case, you need to remove the break-off tab connecting the two sets of like-colored terminals on each side of the receptacle. Otherwise, the tab remains intact, and you can see a metal bridge connecting the terminals.
The important point to keep in mind is that hot (black or colored) wires attach to brass screws and neutral (white) wires attach to silver screws. If the unit is back-wired, the colored wires are located in the holes behind the brass screws and the white wires in the holes behind the silver screws. If you attach a white wire to a brass screw or a colored wire to a silver screw, you may see fireworks.
To replace a standard duplex receptacle, follow these steps:
Turn off the power to the receptacle from the main fuse or circuit panel.
Unscrew and remove the cover plate; then use a voltage tester to make sure that the circuit is dead.
Unscrew the receptacle from the electrical box and pull it out with the wires still attached.
Note where the white and black wires are attached to the old receptacle.
Remove the wires.
Carefully inspect the old receptacle to see if the break-off tab connecting the two sets of terminals on each side of the receptacle is broken off. If it is, remove the corresponding tabs from the new receptacle.
To break off the tab, grip it with long-nose pliers and bend it back and forth until it breaks off.
Attach the wires to the terminals of the new receptacle.
If the wiring has a green ground wire, attach it to the green terminal on the receptacle or to the electrical box.
Push the new receptacle back into the electrical box and screw it in place.
Screw on the cover plate and then turn on the power.