How to Wire a Split Duplex Receptacle

Duplex receptacles are used in homes, apartments and businesses to supply electrical power to various appliances and devices. A split-duplex receptacle appears like any other with the exception that it is wired from two power sources rather than one. One of the two plug-ins may operate a refrigerator while the other provides power for a microwave oven. Both appliances would draw power from their own dedicated circuit breaker using ROMEX® 12-3 grounded cable. Wiring a split duplex receptacle can be done with a few tools, materials and basic electrical knowledge.

Things You'll Need

• Voltage tester
• Utility knife
• Wire strippers
• Needle-nose pliers
• Flat screwdriver
• Phillips screwdriver

Instructions

1. Turn the power off at the main panel for the two circuits to be worked on. Tag or otherwise mark the panel to alert others of the work being done.

2. Test the 12-3 ROMEX® at the duplex box with a voltage tester to verify that there is no power. Touch one probe to the tip of the black hot wire and the other to the white neutral. Also test the hot red wire and the white neutral.

3. Cut 4 inches of sheathing from the ROMEX® 12-3 grounded cable using a utility knife.

4. Strip 3/4 inch of insulation from the white, red and black wires with wire strippers.

5. Bend the ends of the stripped wires and the bare copper ground into open end loops using needle-nose pliers.

6. Remove the tab between the two brass terminal screws on the duplex receptacle. Some receptacles have a break-point between the two brass screws. This tab can be removed by pulling it off with the jaws of the needle-nose pliers.

7. Connect the bare copper ground wire to the green ground post screw. Tighten clockwise using the appropriate screwdriver.

8. Connect the white neutral wire to either of the silver terminal screws. Tighten the screw clockwise.

9. Connect the black wire to the upper brass terminal of the duplex receptacle. Tighten the screw clockwise.

10. Connect the red wire to the lower brass screw and tighten the screw.

11. Wrap several rounds of electrical tape around the receptacle terminals.

12. Push the wiring and the receptacle into the electrical box. Secure the receptacle bracket screws to the box with a screwdriver. Tighten clockwise.

13. Install the box cover and tighten the cover screw with a screwdriver.

Tips & Warnings

• The black hot wire and the red hot wire are connected to their own individual 20 ampere circuit breakers in the main box. The bare copper ground and the white neutral are both connected to the neutral/ground bus in the panel.

• Be sure to keep the open end of the wire loops facing to the right when tightening the terminal screws.

• Ensure that the tab between the two brass terminal screws is completely removed before connecting the black and red wires.

References

• InspectAPedia.com: Multiwire Branch Electrical Circuits and Split-Wired Receptacles
• "The Complete Guide to Home Wiring;" The Editors of Creative Publishing International, Inc.; 2001
• "Residential Construction Academy;" Gregory W. Fletcher; 2004