How to Replace Two-Prong Outlets With GFCI Outlets
Introduction
Replacing outdated two-prong outlets with GFCI outlets is an important electrical upgrade that can protect against electric shocks and electrocution. GFCI, or ground fault circuit interrupter, outlets have a built-in safety feature that cuts off power when it detects any abnormal current flow. Upgrading to GFCI outlets adds an extra layer of protection, especially in areas where water may be present like bathrooms, kitchens, laundry rooms, and outdoors.
While a GFCI outlet replacement project is totally doable as a DIY homeowner project, working with household electrical wiring does carry risks. Be sure to follow all safety precautions and consider consulting a professional electrician if you have any doubts about your abilities.
In this comprehensive guide, I'll walk through the complete process of replacing two-prong outlets with GFCI outlets, including the supplies you'll need, step-by-step instructions, and important safety tips.
Supplies Needed
Before getting started, make sure you have the following supplies on hand:
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GFCI outlets - Purchase new GFCI outlets that match the two-prong outlets you'll be replacing. Both 15 amp and 20 amp GFCI outlets are commonly available.
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Voltage tester - This is an important safety tool that lets you check whether the outlet is live before you work on it.
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Phillips and flat head screwdrivers - You'll need standard screwdrivers to remove the old outlet and install the new one.
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Needle nose pliers - Helpful for grabbing wires in tight spaces.
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Wire strippers - To strip away the insulation on electrical wires.
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Electrical tape - Used to cover exposed wires.
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Circuit tester - Used once the new GFCI is wired to confirm it's working properly.
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Flashlight - To illuminate the electrical box as you work.
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Safety gear - This includes safety glasses, work gloves, and electrical tape.
Turning Off the Power
The first step is to turn off the power to the outlet you'll be replacing. Here's how to do this safely:
- Go to your main electrical panel and locate the breaker that controls the outlet.
- Use a voltage tester to confirm power is running to the outlet. Plug it into the outlet and verify it's live.
- Once you've identified the correct breaker, switch it to the OFF position.
- Go back to the outlet and re-test it with the voltage tester to confirm power is OFF.
Working on an outlet that's live could result in severe electric shock, so always double check with a voltage tester. Never work on a hot outlet!
Removing the Old Outlet
With the power switched off, you can now safely remove the old two-prong outlet:
- Unscrew and remove the cover plate so you can access the outlet wiring.
- Unscrew the top and bottom mounting screws that hold the outlet in place. These screws are usually brass-colored and located on the left and right side.
- Carefully pull the old outlet out from the electrical box but leave the wires connected. Don't detach the wires yet!
As you pull out the outlet, pay attention to how the wires are connected and oriented so you can recreate these connections later.
Pigtailing and Connecting New Outlet
Here's how to make the wiring connections for the new GFCI outlet:
- The GFCI outlet will have hot/live, neutral, and ground wires attached. You'll be matching these up to the existing outlet wires.
- The neutral/white wires from the existing outlet get connected to the neutral silver screw on the GFCI.
- The hot/live wires, usually black, get attached to the hot brass screw.
- For grounding, you'll need to add 6" pigtails (short jumper wires) to connect the box grounding wires to the green ground screw on the GFCI.
- Twist the like-colored wires together securely using wire nuts and tighten these connections.
- Ensure exposed copper wires are fully inserted into the screw terminals so no copper shows. Tighten the terminal screws securely.
DO NOT disconnect any wires from the existing outlet yet. The pigtailing technique allows you to make new connections without temporarily killing power to other outlets.
Installing the New GFCI Outlet
You're now ready to securely install the new GFCI outlet into the electrical box:
- Carefully insert the new outlet into the box, matching the wires correctly.
- Tighten the top and bottom mounting screws securely to hold the outlet in place. Do not overtighten.
- Attach the cover plate and screw it into place.
- With the outlet fully installed, carefully push all the wires back into the box so they are not pinched.
Restoring Power and Testing
You're almost done! Follow these final steps to complete the GFCI installation:
- Return to the main electrical panel and switch the appropriate breaker back to the ON position to restore power.
- Go to the outlet and use a circuit tester to confirm power is running correctly to the GFCI. Look for the "correct wiring" indication.
- Press the "Test" button on the GFCI. This should immediately trip the outlet and cut power. If it doesn't, don't use the outlet and call an electrician.
- Pressing "Reset" should restore power to the GFCI outlet. Confirm with a circuit tester.
If the GFCI outlet is tripping and resetting properly, then it's wired safely and ready for use! Be sure to test GFCIs monthly.
Safety Tips
Replacing outlets comes with electrical risks, so safety should be your top priority.
- Never work on outlets with wet hands or wear wet shoes.
- Use a non-contact voltage tester to confirm the outlet is dead before working.
- Turn off power at the breaker, not just the light switch.
- Cap all wires with wire nuts when not connected.
- Only connect like-colored wires together (match hot to hot, neutral to neutral).
- Ensure electrical boxes remain deeply recessed and aren't protruding.
- Never leave exposed copper wires - always fully insert into terminals.
If at any point you feel unsure or unsafe, stop work immediately and call a qualified electrician. Safety first!
Conclusion
Upgrading two-prong outlets to GFCI outlets is one of the best investments you can make for home electrical safety. While it requires working carefully with household wiring, it's an achievable DIY project for many homeowners. Follow proper precautions, take it step-by-step, and you'll gain essential electrical skills. Just be sure to always put safety first given the risks involved.