Attaching 2 Electrical Outlets in Parallel

In order to have an alternative access of electricity and also reduce the usage of extension cords, you can simply add an additional outlet inside your room or even garage area. You can do wiring of an outlet in parallel by wiring a new outlet onto an existing outlet or it is also known to some electricians as “daisy-chain” wiring. The outlet needs to be wired together by using standard 14-2 gauge romex cable. This romex cable comes with two insulated wires and a bare ground wire.

What you need to do:

  1. Screwdriver
  2. Measuring tape
  3. Pencil
  4. Keyhole saw
  5. 1 roll, 14-2 gauge romex cable with ground wire
  6. Wire cutters/strippers
  7. Electrical outlet box
  8. 110-volt electrical outlet
  9. Non-contact voltage tester
  10. Two duplex electrical receptacles
  11. Razor knife
  12. Adjustable wire strippers
  13. Needle-nose pliers
  14. Black, plastic electrical tape

Electrical Outlets


  1. Firstly, you must ensure and double check that the circuit breaker has been turned off at your main service panel which is supplying the power to your outlet. Always take this safety precaution whenever you are dealing with electricity.
  2. The next step is to remove the screw that holds the cover plate of your outlet and place it in a safe place so that it is easier for you to re-assemble them later.
  3. Then, remove the two screws on top and bottom that holds the outlet onto the outlet box before slowly sliding the outlet out of the box. Make sure that you leave the existing wiring still connected to each other. After that, you need to use your screwdriver in order to punch out one of the knock-out holes that can be found at the back of your electrical box.
  4. Determine the area that you want to install your new outlet and measure the space up from the floor 18 inches. You need to mark your measurement on the wall and line up the top of your new electrical box in-line with the mark.
  5. Then, you have to trace along the outside of the box in order to trace the size of your box onto the wall area. Next, you have to cut out the trace that you have done using the keyhole saw so that you would be able to make a hole, which is large enough to slide the box into it.
  6. After that, put one of the knock-out holes you see at the back of your new outlet box using the screwdriver and slide the box into the wall. Make sure that you secure its screws accordingly using your screwdriver.
  7. Then, you have to run the new 14-2 electrical cable from your existing outlet box to the location of your new outlet box and pull at least 6 inches of cable from each box so that you would be able to wire to the outlets.
  8. Next, you need to strip at least 3 inches of the outer sheathing off the end of the cable that you see coming out from the new outlet box. You will find three separate wires inside the outlet where two of them are for the insulated and the other one is for the bare wires.
  9. Then, you must strip at least 1 inch of insulation off from the two insulated wires and repeat the same step, but this time for removing the sheathing and insulation off the end of the cable that you see coming out of the existing box.
  10. After that, you have to attach your new outlet to the wiring at your new outlet box where the bare wire needs to be attached to the green screw, the white wire to the silver screw, while the black wire needs to be attached to the brass screw. In order to hold all the wires in place, you need to tighten each of the screws down on the wires. Once you finish securing the screws, you must attach the outlet onto the outlet box by using the included screws and ensure that it is tight and secured before attaching the box cover plate.
  11. Next, you need to attach the wiring onto your existing outlet before tightening its screws. Then, you have to attach the bare wire onto the green scew, white wire to the bottom silver screw and as for the black wire; it needs to be attached to the bottom brass screw. Once finished, you need to attach the outlet back onto the outlet box before replacing the cover and tightening its screws.
  12. Finally, you have to turn back on the power at your service panel and do some simple testing to see whether your installation is workable or not. For example, you can plug in a lamp onto the new outlet and test its operations.

Image Credit:

Flickr CC

Additional Reading:

How to Wire Electrical Outlets, Switches, and Lights (Home Care Guide)

Wiring Simplified: Based on the 2008 National Electrical Code