To add a new outlet to a group of receptacles already in place, splice the new wires to one set of wires on one of the existing receptacles. In this diagram each receptacle is wired to the next using the terminals to pass the voltage along. To provide voltage to a new receptacle, remove the wires from one set of terminals on the existing outlet and splice in the new wires and a pigtail back to each terminal.
This circuit breaker wiring diagram illustrates installing a 20 amp circuit breaker for a 240 volt circuit. The 12/2 gauge cable for this circuit includes 2 conductors and 1 ground. A dedicated 20 amp circuit like this is used for heavy household appliances like an air conditioners.
The always-hot wire from the receptacle is spliced to the black wire on the fixture cable, and to a pigtail that connects back to the hot terminal on the receptacle. At the light fixture box, the black is spliced to the black from the switch cable. At the switch box the black wire is connected to the bottom terminal on the new switch.
This wiring diagram illustrates wiring a light switch to control an existing receptacle outlet. The source is at the receptacle and a switch loop is added to a new switch. The hot source wire is removed from the receptacle and spliced to the red wire running to the switch. The black wire to the switch connects to the hot on the receptacle.