How To Add An Outside Outlet To Your Back Porch

Posted on: 17 February 2017

You have been wanting to add an electrical outlet to your back porch for a long time, but never had enough incentive to do it. However, Valentines Day is approaching, and what better way is there to add a little bit of magic to the evening than to install multiple strands of small LED "fairy" lights to surprise your Valentine?

You can power an exterior outlet from a nearby interior outlet without too much effort and a minimal amount of tools or electrical skills.

What do you need to install an exterior outlet?

  • GFCI outlet: A GFCI (ground fault circuit interrupter) outlet is used in potentially wet locations and shuts off when improper grounding is detected.
  • Open face plate: This is the cover that hides a GFCI outlet
  • Outdoor single gang box and plastic cover: This is a metal box that hangs on the wall to hold the outlet. You can buy the gang box with a flip down cover to protect it from rain and wind, or install a separate cover.
  • 1/2" EMT conduit, with fittings and connectors: Conduit is thin metal tubing through which your wire will run. You will need enough conduit to run from your source outlet indoors to the proposed location of the exterior outlet. You will also need fittings to change the direction of the conduit, such as 90 degree elbows, as well as connectors that attach the conduit to both gang boxes.
  • Hacksaw for cutting conduit
  • Hammer drill with 5/8" SDS bit: You'll need to drill through the exterior wall to run the 1/2" conduit, but you can rent a hammer drill from your local home improvement store.
  • Screwdrivers (flat and Philips head)
  • Wire

Check the breaker that controls the flow of power to your source outlet to determine the gauge of wire needed. You will need a three wire sheath of 14 gauge wire for a 15 amp line (breaker is stamped "15"), and 12 gauge wire for a 20 amp line. Wire length requirements will be found by measuring the intended path between the two outlets and adding several feet to the length for connection purposes.

Removing the interior source outlet

You'll need to remove and replace the interior outlet, so you must turn off the breaker to the source outlet. When this is done, you will unscrew the cover plate and the two securing screws for the outlet, then loosening the diagonal screws that hold the gang box inside the wall.

Next, pull the outlet from inside the gang box and  disconnect the three wires from the screw terminals. Remove the gang box from the wall, then push out the punch out tab in the back of the gang box and replace the gang box inside the wall.

Use a marker to mark the location of the punchout hole in the back of the gang box on the inside wall, then remove the gang box and use the hammer drill to drill through the exterior wall at the mark.

Replace the gang box and measure the distance from the exterior wall to the back of the gang box, then cut a piece of 1/2" conduit to that length.

Pull out the gang box and twist a conduit connector into the hole,then connect the piece of cut conduit and push the conduit through the wall while replacing the gang box. Secure the gang box inside the wall.

If you simply want the new outlet in the same approximate location as the source outlet, you can connect a 90 degree elbow to the end of the conduit and cut another piece to the height desired for the new outlet. If you want it in another location, you will need to cut additional pieces of conduit and add multiple connectors.

You will finally attach a connector to the end of the conduit, punch out a tab on the bottom of the new gang box, then attach the gang box and screw it into the exterior wall.

Gang box: Connecting the wiring to the old outlet

You will begin by stripping 3/4" of insulation from the ends of each of the three wires in the sheath,then begin to run the wire sheath from the new location through the new gang box and each piece of conduit, making connections as the sheath passes through, until the wire ends reach the interior source gang box.

Pull the wires through, then connect the black wire to the lower brass terminal, the white wire to the lower silver terminal, and the green wire to the top green terminal. Push the outlet inside the gang box and tighten the screws, then restore the cover plate.

Wiring the exterior outlet

Cut the wire sheath at a distance of 6 inches from the gang box and strip the ends of the three wires, then connect the black wire to the top brass terminal, the white wire to the top silver terminal ,and the green wire to the single green terminal on the GFCI outlet.

Push the outlet into the gang box, then place the open cover plate over the outlet so the two connecting screws go through both the plate and the outlet.

If you have a separate plastic cover, install it according to directions, turn on the breaker, push in the rest button on the GFCI outlet, and you're ready to fill the porch with starlight.


Talking About Electrician Services

Hi all, I’m Josiah. Welcome to my site about electrician services. When I was living in a home built in the 1940s, I came across a number of troublesome wiring issues. The wiring was old and in a state of serious disrepair. When I plugged in more than three electronics on the power strip, the breaker would blow and shut down my entire system. I had the entire home rewired to rectify this problem once and for all. My site will cover all sorts of electrician upgrades and repairs. I invite you to visit often to learn about upgrades to use for your own home.