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.
In these cases, it should be wrapped with electrical tape to mark it as hot. The ground wires will be green and/or bare copper. The ground should be spliced with a short piece of wire and connected to each device and outlet box that has a grounding terminal. In these drawing the brass colored terminal represent the hot side of the device and the silver colored terminal represent the neutral. Ground wires and terminals are in green.
This page contains wiring diagrams for two outlets in one box. Included are arrangements for 2 receptacles in one box, a switch and receptacle outlet in one box, and 2 switches in the same box. In this diagram, two duplex receptacle outlets are wired using pigtails spliced to connect the terminals of each to the source wires.
This page contains several diagrams for 2 or more receptacle outlets in one circuit. Wiring for multiple ground fault circuit interrupters (gfci) and standard duplex receptacles are included with protected and non-protected arrangements.