Screw Terminal vs. Push-Fit Connections
Electrical outlet receptacles come with two means of making the wire connections: they have push-fit openings on the back of the receptacle, as well as screw terminals on the sides of the receptacle body. Either method can be used to make the circuit wire connections.
While DIYers often favor push-fit connections because they are very easy to make (you simply strip off about 1/2-inch of insulation from each wire and push it into the connection opening), professionals and knowledgeable DIYers almost always use the screw-terminal connections on the side of the receptacle.
The reason? Push-fit connections usually hold the wire with a inner spring-metal arm that can lose its resiliency over time, causing the wire to loosen. Because professionals want to avoid call-backs to repair their work, they almost always use screw-terminal connections. The same is true for any DIYer who has experience with home wiring repairs.
Granted, screw-terminal connections are a little harder to make, but when correctly done, they create very durable wire connections that are not likely to loosen. The technique is fairly easy to learn, and it involves stripping the wires, bending the bare wire into a C-shaped loop to fit around the screw terminal, and tightening the screw down to grip the wire.
Anatomy of an Outlet Receptacle
Standard outlet receptacles will have a total of five screw terminals: two silver-colored screw terminals for attaching neutral circuit wires, two bronze or copper-colored screw terminals for the hot circuit wires, and a green screw terminal fixed to the strap of the receptacle, which is used for the bare copper ground wire or a green ground pigtail wire. For each of these screw terminals, the connections are made exactly the same way.
Tools and Supplies You Will Need
- Combination tool or wire stripper
- Needlenose pliers
Loosen the Side Screws on the Receptacle
Loosen each screw terminal you will be connecting on the outlet receptacle to its full length. Screw terminals that won't be used should remain fully tightened down. Having the screw at its full length will make it easier to loop the wire around the screw.
Strip the Wire
Next, you must strip off the insulation from the circuit wire. An electrician's comination tool or wire stripper is the best tool for this. Most receptacles have a wire gauge printed or stamped into the plastic body of the receptacle, which will indicate how much insulation needs to be stripped off.
Insert the wire into the appropriate hole on the wire stripper or combination tool, and lever the handles to remove the insulation from the tip of the wire. Make sure to use the correct gauge for the wire gauge; using the wrong hole can damage the wire.
Bend the Wire
Next, the exposed end of the wire needs to be bent into a C-shaped loop to fit around the screw terminal. Bending wire for side wiring a receptacle is both a craft and an art. Experienced electricians or do-it-yourselfers learn to do this step quickly since each outlet may have as many as five screws that need wire connections. There are several tools that can be used for this.
Some screwdrivers have a little nub parallel to the screwdriver's shaft that allows you to bend the wire into a loop. Place the wire between the nub and the shaft, then turn the screwdriver until you have formed a loop in the wire. This is the method of choice for most electricians, sine there are no flat surfaces to distort the wire, and the screwdriver shaft forms a perfectly smooth loop in the wire.
You can use the very end of a pair of needle-nose pliers to create a C-shaped loop on the wire. Grab the tip of the wire with the plier jaws, then twist the tool to create a loop.
Most wire strippers will have holes of different gauges built into the handle meant for bending the wire. This tool works differently from the screwdriver and pliers, as it is more difficult to form a C-shaped loop. Some wire strippers have gripping jaws that let you bend wire just as you would using needle-nose pliers.
Connect the Wire
To make the wire connection, first place the bare loop of the wire around the shaft of the terminal screw, with the loop positioned in a clockwise direction. Done this way, the screw head will force the wire loop to close as it tightens down onto the wire. (If the wire is looped counterclockwise, the screw may cause the wire loop to open up as it tightens down.
As the head of the screw just touches the wire, examine the loop. If it is not quite closed, you may be able to force it closed using the tip of a screwdriver or needle-nose pliers. Ideally, the entire wire loop should be covered by the screw head, and the insulation on the wire should just touch the screw, with no bare wire showing. (In this demonstration photo, a generous amount of insulation has been removed in order to show the wire loop. In practice, the insulation should just touch the screw.)
Complete the connection by tightening the terminal screw slightly further, but take care not to strip the screw threads or flatten the wire. Tug firmly on the wire while gripping the receptacle to make sure the wire connection is secure.