How to Wire a GFCI Outlet When Replacing a 2-Prong Outlet

Replacing an old 2-prong outlet with a GFCI outlet is a great way to add safety and protection from electrical shocks in your home. While it may seem daunting, wiring a GFCI outlet is easier than you think if you follow some basic steps.

What You’ll Need

Before getting started, make sure you have the following materials:

  • GFCI outlet
  • Wire strippers
  • Needle-nose pliers
  • Phillips screwdriver
  • Electrical tape
  • Voltage tester

Turn Off Power at the Breaker

Safety should always come first when working with electrical wiring. Locate the circuit breaker that controls the outlet you’ll be replacing and switch it to the “OFF” position. Double check that the power is off by using a voltage tester on the outlet.

Remove the Old Outlet

Use a Phillips head screwdriver to remove the cover plate screws and pull the outlet from the electrical box. Carefully disconnect the wires attached to the outlet and detach it completely.

Connect the Wires

GFCI outlets have five wires – a line hot, line neutral, load hot, load neutral, and ground. The line wires bring power into the outlet, while the load wires send power out to other outlets in the circuit.

Connect the black LINE hot wire to the darker copper terminal, the white LINE neutral wire to the lighter terminal, and the bare copper GROUND wire to the green screw. Cap off the LOAD neutral and hot wires separately if there are no other outlets connected downstream.

Install the New GFCI Outlet

Gently stuff the wires into the electrical box, secure the GFCI outlet, and install the cover plate. Make sure no wires are pinched or crushed.

Restore Power and Test

Turn the circuit breaker back on. Press the “TEST” button on the GFCI outlet to confirm protection is working properly and reset it. Test your outlet with a voltage tester to make sure there’s power.

Important GFCI Outlet Safety Tips

  • Never install a GFCI outlet near water sources without a proper in-use cover.
  • Test GFCI outlets monthly to ensure they trip when needed.
  • Avoid overloading GFCI outlets with too many appliances.
  • Only reset the GFCI if you are certain it tripped for a safe reason.
  • If a GFCI trips repeatedly, it likely indicates an unsafe wiring issue.

Replacing a 2-prong outlet with a GFCI outlet provides an extra layer of protection from dangerous electrical shocks. Following proper safety procedures keeps you and your home safe. With a bit of care and some basic wiring knowledge, upgrading to a ground fault circuit interrupter outlet is a DIY project anyone can tackle.

Frequently Asked Questions About Wiring a GFCI Outlet When Replacing a 2-Prong Outlet

How do I identify the line and load wires?

The line wires that bring power into the GFCI outlet are usually the black (hot) and white (neutral) wires that were connected to the old outlet. The load wires that send power to other outlets are usually tucked into the back of the electrical box.

What is the purpose of the GFCI LINE vs LOAD terminals?

The LINE terminals power the GFCI outlet itself. The LOAD terminals protect and control power to additional outlets downstream in the circuit.

Can I use the old 2-prong outlet wires for the GFCI?

Yes, the standard black and white wires from the old outlet can connect to the LINE terminals on the GFCI to power it directly.

What if I don’t have a ground wire?

For 2-prong outlets without a ground wire, you’ll need to install a GFCI outlet with no equipment grounding conductor. Make sure it is properly labeled.

Why won’t my GFCI reset after testing it?

If a GFCI outlet won’t reset after testing, it likely means it is functioning properly and detected a ground fault somewhere in the circuit wiring. This should be inspected by an electrician.

How often should GFCI outlets be tested?

Experts recommend testing GFCI outlets monthly to ensure they are working correctly and will trip when needed to prevent shocks.

Can I install a GFCI outlet outdoors?

Yes, GFCI outlets installed outdoors must be rated for weather-resistance. Make sure the GFCI outlet has a waterproof cover.

How do I safely replace a GFCI outlet?

Always turn off power at the breaker, use a voltage tester to confirm it’s dead, match all wires correctly, install the outlet securely in the box, and test the outlet before turning power back on.

Why choose a GFCI over a normal outlet?

A GFCI outlet provides protection from lethal electric shocks by detecting ground faults. This extra safety measure greatly reduces the risk of electrocution or injury.


Installing or replacing a GFCI outlet is a wise upgrade to protect your home from electrical hazards. Pay close attention to connecting the LINE and LOAD wires properly. With the power turned off and wires handled safely, it’s a straightforward project that homeowners can tackle themselves. Always follow precautions like testing GFCI outlets regularly. A small investment in this added safety measure can prevent huge risks from electrical shocks.