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.
An isolated-ground receptacle makes use of an extra wire for a separate ground in the circuit. This is the red wire in the 14/3 cable used here which is marked and connected to the grounding terminal on the receptacle. The other cable wires are connected as with any other circuit except for the ground wire. The bare copper ground wire is NOT connected to the receptacle, instead it is connected to the grounding terminal inside the electrical box where the receptacle is housed.
This diagram illustrates some of the most common circuits found in a typical 200 amp circuit breaker box. The breakers are installed in a service panel so that contact is made with one of two hot bus bars that run down the middle of the box. The hot wire for a circuit is connected to the breaker by a set screw on the base.
The wiring in this diagram is for adding a new light fixture to a switched receptacle, i.e. one that is hot only when a switch is on. These are commonly used to turn a table or floor lamp on and off from a wall switch.