This diagram illustrates a switch and receptacle in the same outlet box located in the middle of the circuit. This wiring allows the electricity to continue from the receptacle, on to any other outlets in the circuit and it provides a switch to control a light fixture or other load, such as another receptacle or a fan.
The hot wire to the fan in a fan/light kit will usually be black and the light wire will be blue. The white wire is usually the neutral which is always connected directly to the source neutral, either at the source or through a splice in the switch box. The white wire may also be used to carry current when necessary.
Here one ground fault circuit interrupter protects multiple duplex receptacles coming after it, known as multiple-location protection. Two-wire cable runs from the gfci to all the following receptacles. The line terminals on the gfci are connected to the circuit source and the load terminals are connected with a pigtail splice to each of the following receptacles. This keeps each duplex connected directly to the gfci.
This gfci wiring provides protection to a duplex receptacle. By connecting the load terminals on the last gfci, the receptacle is protected and can be used just as if it were one of the gfci receptacles. One ground fault circuit interrupter at the beginning of the circuit can be used in the same way to protect multiple, subsequent receptacles as illustrated in the diagram below.