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Outdoor GFCI Electrical Outlet Installation

If you use outdoor electrical outlets for holiday lights or other things that need a plug (karaoke machine anyone) then a GFCI outlet is a must. House electrical wiring needs GFCIs in kitchens, bathrooms, and anywhere outside.

Ground-fault circuit interrupters are special electrical outlets. If there is a ground fault the GFCI will trip (like a circuit breaker) and quickly stop electricity from flowing through a person’s body to get to the ground.

Put another way, GFCIs are a part of your home’s nervous system. They take care of electrical safety issues without you having to give much thought.

But you should test them monthly to make sure they work. Who wants to be shocked while singing their rendition of Elvis Presley’s Blue Suede Shoes in front of their friends and neighbors. This would be bad, real bad.

At the end of this post, you’ll have the ability to replace an old electrical outlet with a GFCI outlet and test your work for correctness.

Supplies for GFCI Electrical Outlets

Here are the supplies you’ll need:

  • GFCI Outlet
  • Voltage Tester or Detector
  • Electrical Tape
  • Rubber-Grip Screwdrivers
  • Combination Stripper
  • GFCI Receptacle Analyzer

I replaced an outdoor electrical outlet that wasn’t a GFCI because my daughters are getting older and plugging electrical devices like iPods into outlets themselves. I love them and their safety is super important.

If you feel the same way about your family and friends then what I have to share will ease your fears of electrical shock.

Let’s dive in.

How to Identify the LINE & LOAD Cables for an Outdoor GFCI Electrical Outlet

Turn off the power to the old outdoor electrical outlet at the service panel (unless you like to live dangerously). Check that there’s no electricity running to it with either a voltage tester or detector.

Remove the cover plate with a rubber-gripped screwdriver then test all the wires for power. Even test the wires you’re not working with because they might have electricity running to them. Confirm the voltage tester is working by inserting it in to a live receptacle.

Again,  test the power by touching the probes of your voltage tester to a hot wire and a grounded box, to a hot wire and a neutral wire, or insert them into the neutral & hot slots in the outlet.

I used my handy dandy voltage detector a second time for this step. Getting shocked wouldn’t please my insurance agent or my wife?

Outdoor GFCI Electrical Outlet-Test for power

In order to understand how to install GFCI outlets, you need to understand LINE vs. LOAD cables.

A typical electrical cable has 2 or 3 wires. A bare copper wire is the ground. The white wire is the neutral. And finally, the black wire is Darth Vader, it’s the hot evil wire that will kill you. Think of yourself reaching in and BAM! The Darth Vader wire shocks your right hand.

Hey, consider yourself lucky. Luke Skywalker got his hand cut off. Moral of the story: be careful and work on wires with the electricity off.

Anyhow, LINE cables deliver power from the service panel to the electrical outlet or GFCI in this case. If you’re lucky there will only be one cable entering the electrical box and it’s the LINE cable. It should be connected to the GFCI’s LINE terminals.

LOAD cables deliver power from the outlet (GFCI in this example) to another outlet in the circuit. This cable needs to be connected to the GFCI’s LOAD terminals.

Here’s a video that shares more information on LINE vs. LOAD as wells as how to safely remove old outlets.


The directions to the Pass & Seymour GFCI I used stated not to install it in an electrical box containing more than 4 wires (not including the ground wires) or with cables that have more than two wires (not including the ground wires). The latter case would be a cable that has a white, black, and red wire. You’ll need to call an electrician for these instances.

My outdoor electrical outlet had two cables entering the electrical box. The proper way to test LINE and LOAD cables is to disconnect one cable’s white and black wires. Cap each wire separately with a wire nut, i.e. one nut on the white neutral wire and one nut on the black hot wire. Just make sure the wires are from the same cable.

Next, re-install the outdoor electrical outlet into the electrical box, replace the faceplate, and turn the power on at the service panel.

Test to see if power is running to the outlet. If you have power in the outlet the capped wires are the LOAD wires. If power isn’t running to the outlet the capped wires are the LINE wires.

Turn the power off at the service panel and immediately label the LINE and LOAD wires. The next person will thank you and think you’re a genius-which you are, right!

How to Install an Outdoor GFCI Electrical Outlet

Once the electrical cables are labeled LINE and LOAD you can easily install an outdoor GFCI  electrical outlet.

I used emery cloth to clean up the old copper wires. This helps create better contact between the copper and GFCI terminals.

Outdoor GFCI Electrical Outlets-Use emory cloth to clean up old copper wires

Connect the bare copper ground wire to the green terminal screw on the GFCI. Then connect the white LINE wire to the silver LINE terminal and the white LOAD wire to the silver LOAD terminal. Do the same procedure for the black LINE and LOAD wires only this time connect them to the brass terminals on the GFCI.

If you have a wire that was wrapped in electrical tape inspect the tape for wear and tear. If the old tape is in poor shape (think Jabba the Hutt) replace it with new electrical tape. I had to do this for about 3-inches of the white neutral wire.

Push all the wires to the back of the electrical box. Keep the bare ground wire away from the white and hot terminals on the GFCI.

Go ahead and screw the outdoor GFIC outlet to the electrical box then attach the faceplate.

Now is the time to test your work. Are you a true GFCI Jedi Knight? To help you with your training Yoda and I put together this video.

Testing an Outdoor GFCI Electrical Outlet 

You should test the GFCI outlet because if it’s mis-wired it may not protect someone from a ground fault, aka electrical shock.

Go ahead and turn the power on at the service panel.

Press the RESET button. It should stay in the GFCI.

If the button doesn’t stay in the GFCI you’ll need to visit the troubleshooting section of your directions.

If the button does stay in you should plug a lamp into the GFCI to verify there is electricity running to the outlet. If the lamp doesn’t light up you’ll have to visit the troubleshooting section (sorry for the bad news).

Now press the TEST button to trip the GFCI.

This will shut off the lamp because the flow of electricity has stopped. The RESET button should pop out.

If power remains on you haven’t wired the GFCI correctly and again need to visit the troubleshooting section (it’s like going to detention).

If the power remains off you’ve installed the GFCI the right way and deserve a drink (away from electrical devices I might add). Restore power by pressing the RESET button. The light will come back on.

Here’s a bonus video that shares how to install an exterior GFCI outlet cover, which comes in handy when you have lights plugged in during the holidays.

If you’re using any kind of outdoor accent lights for the holidays or a party please make sure they’re plugged into a GFCI protected outdoor electrical outlet. Again, the last thing you want is for someone to be sipping their favorite drink then get shocked by faulty wiring. It’s a huge bummer (and liability).

What’s Next

Don’t forget, GFCIs are also required in bathrooms by electrical code – our detailed tutorial shares how to install them step-by-step.

If you’re doing a bathroom remodel and need help, join one of our online courses – they’ll make your bathroom renovation much easier!

Let me know if you have any questions and I’ll do my best to help.



Exterior GFCI Installation