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.
Use this wiring when the power source originates at the switch and you want to control both the fan and light from there. The hot source is connected directly to the bottom terminal on the switch. Two-wire cable runs from there to the ceiling fan.
The source hot is spliced to the red wire which is connected to the bottom terminals on the switch at the other end. The black wire is connected to the top terminal on the switch which runs power back to the fan where it is spliced to both the black and blue fan wires.
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.