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 is similar to the one above, but with the electrical source originating at the fixture. Three-wire cable runs from there to the controllers. The neutral wire from the source is spliced directly to the white wire on the fan/light. The hot source wire is spliced to the white on the 3-wire cable and then spliced to the input wires on both controllers at the other end.
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.
Here GFCI’s are wired to a double-pole circuit breaker with the source split to provide 120 volts to two sets of receptacles. The neutral from the source is shared by both sets. Single-location protection is provided by each receptacle.