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 shows the wiring for multiple receptacles in an arrangement that connects each individually to the source. All wires are spliced to a pigtail which is connected to each device. This wiring allows for voltage at each device independent of the other outlets in the circuit.
This wiring diagram illustrates the connections for dual controls, a speed controller for the fan and a dimmer for the lights. The source is at the controllers and the input of each is spliced to the black source wire with a pigtail. From the controllers, 3-wire cable runs to the ceiling outlet box.
Here 3-wire cable is run from a double-pole circuit breaker and split to supply 120 volts to two sets of receptacles. The neutral wire from the circuit is shared by both. This wiring is commonly used in a 20amp kitchen circuit where two appliance feeds are needed, such as for a refrigerator and a microwave in the same location.