Everyone should know a little about basic outlet wiring. The most common method of wiring involves a circuit with multiple joined outlets that begin at the main supply breaker box and end at an outlet, switch or light. Outlets use 120-volt circuits with romex 12/2, 12/3, 14/2 or 14/3 wire. Romex is the common name used for the electrical wire. The first number designates the gauge (the higher the gauge, the smaller the wire), and the second number designates the amount of wires inside (not including the ground wire). The larger wires do not heat up as easily, so they are used for larger appliances or loaded circuits.The 12 gauge is used more often for outlets than the 14 gauge. The circuit should have no more than 15 loads on it. Each outlet is one load. Using this information, a basic circuit can be described for wiring multiple outlets.
Turn off electricity before beginning a wiring project. Draw a diagram showing where each outlet will be located in the room It is best to do this on a floor-plan drawing which also helps to keep the lines straight and organized.
Install a junction box where each outlet will be located. These are typically plastic boxes that hold the wires behind the outlet, but in some cases, metal boxes are used.
Drill a hole in the center of each stud in the wall that the wire will run through. Check local codes to determine if a height is specified. Line up all junction boxes and holes in the studs at the same height for easier installation.
Run the romex wire from the breaker through the walls to the first outlet. The black hotwire is directly connected to the breaker, while the white wire and the ground wire (which is either copper or green) are connected to the bus bar.
Use an electrical stapler to secure the wire to the studs in areas where it is loose or hanging. You can tap the staple in place with a hammer. At the junction box, staple an 8-inch loop, then run the wire into the junction box, also allowing 8 inches of wire to hang out into the box.
Begin a new wire from inside the junction box, again allowing 8 extra inches. Then continue the wire out of the back of the box, through the holes in the studs to the next outlet junction box.
Run the wire to each junction box needed in the circuit. The last junction box will have only an incoming wire and no outgoing wires.
Purchase the amount of outlet receptacles needed for each junction box. If the outlets are going to be used in a bathroom, outside or in a kitchen, use ground fault circuit interrupter, GFCI, outlets, which are required in these areas based on the electrical code.
Strip the wire at each junction box (both the incoming and outgoing wire ends) 3/4 of an inch, exposing the copper wire.
Cut extra wire lengths of 6 inches to create pigtails to complete the circuit for each outlet. Strip the ends on both sides of these wires. The black, white and ground wires will all be separated for these pigtails.
Using the pliers, bend the ends of one side of the pigtail in a semicircle so it fits around the screws on the outlet.
For each outlet, gather all black wires: one each from the incoming wire, the outgoing wire and the pigtail. Keeping the exposed wires straight together, use the screw nut on the three wires and twist one to secure. Pull each wire lightly to make sure they are connected. Repeat for the white and ground wire.
Take the pigtail wires and place the semicircle end around the screw on the outlet. The black wire will go to the gold screw, the white wire to the silver screw and the ground wire to the green screw. Tighten the screw until secure.
Place the wires in the junction box and screw the outlet receptacle onto the junction box.