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.
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.
Here the exhaust fan is controlled by a timer instead of a switch. There should be two hot wires and a ground coming out of the timer casing, splice one of these to the hot source. Spice the second to the black, cable wire running to the fan. Splice the source neutral to the white cable wire and the ground to the ground wires. At the fan splice the wires, matching the colors of each.
In this diagram wall outlets are wired in a row using the terminal screws to pass voltage from one receptacle to the next. In this diagram, multiple receptacles are connected together using the device, instead of a pigtail splice as shown in the next diagram. Using this method, any break or malfunction at one outlet will likely cause all outlets that follow to fail as well.