Wiring a double outlet can be done from a single circuit using a parallel design. This allows the other outlet to continue working if the other one fails and balances the electrical load evenly between the two. Working around electricity is extremely dangerous if you don't turn the power off at the source first. Less than one amp of power will stop the human heart and an outlet circuit has 15 amps. Have your local building authority inspect your installation before using the outlet.
Turn off the power for the wires you are working on at the home's distribution panel. Confirm the power is off by touching a non-contact voltage detector to the wire's insulation.
Strip 3/8 inches of insulation off the three conductors coming from the distribution panel.
Cut two sections of 14/2 gauge wire to go between the source wire and the outlets. Strip 3/8 inches of insulation off the conductors on both ends of the wires.
Twist together the source black wire with the two black wires for the outlets with pliers. Install a twist-on wire connector on top. Repeat this process to connect the three white wires and three green or bare wires.
Loosen the two grounding terminals in the back of the outlet's electrical box. Wrap one green wire around each terminal and tighten them down.
Loosen the brass and silver terminals on the outlets with a screwdriver. Wrap one of the black wires around one of the outlet's brass terminals and tighten it down. Wrap the same wires (white conductor) around the silver terminal and tighten it down. Repeat this process to wire the other outlet.
If your are wiring kitchen outlets, you will need 12/2-gauge wire to accommodate the 20-amp receptacles.