This diagram illustrates the wiring for a circuit with gfci receptacles followed by a light and switch. By connecting the switch to the load terminals on the gfci, the light is protected against ground faults as well.
In this diagram, two receptacle outlets are wired in the same box with a separate 120 volt source feeding each. Three-wire cable runs into the box. The black and red wires are hot and each is connected to one of the receptacles. The white, neutral wire is splice to each outlet so they share the return path. This is appropriate for standard duplex receptacles, but should not be used for GFCI receptacles. GFCI’s must have dedicated neutral connections to work properly.
Here a gfci receptacle is added at the end of a row of duplex receptacles for single-location protection. The first outlet is connected to the source and 2-wire cable runs from box to box. All wires are spliced with a pigtail at the devices to pass current from one to the next. The load terminals on the gfci are not used and it does not protect the other receptacles in the circuit.
This diagram illustrates the wiring for a Cooper gfci/switch combo device wired to protect a garbage disposal. With this arrangement a receptacle, switch and disposal are protected with the ground fault breaker built into the device.