How to Test a GFCI Outlet

A GFCI outlet.
  • 1 hours
  • Beginner
  • N/A
What You'll Need
Lamp (or other appliance)
GFCI outlet
What You'll Need
Lamp (or other appliance)
GFCI outlet

Ground fault circuit interrupt outlets or a GFCI outlet are very popular electrical outlets used in homes all around the world. Although this technology has been around ever since the 1970s, it's only recently starting to become a popular addition to many homes. These GFCI outlets are commonly fitted to high-risk areas of your home, including any damp or wet areas. If any outlets are installed in kitchens, outdoors, or in bathrooms then a GFCI will often be the safest and easiest way to accomplish this.

The idea of a GFCI outlet is to compare the current going out on the "Hot" leg with the current returning on the "Neutral" leg. If there is any difference as little as 5 milliamps between them, it will trip the circuit. This difference in current can only be caused by current taking another route. It can be caused by passing through someone else.

These outlets are safety devices and so it's important to check that they are in good working order. You should be checking their condition every couple of months to ensure that they will be able to save your life if they are ever needed.

Step 1 - Plug in the Lamp

A lamp is very practical for testing the outlet as it makes it very easy to identify when the circuit has been tripped and has stopped supplying power. Any other appliance is suitable for use, however, it will be much simpler when using a lamp because it's easy to move it around and it will also trip instantly.

Once the lamp is plugged into the GFCI outlet, turn it on and make sure that it's functioning as it should be. If there is no power being received by the outlet then you should check that the outlet hasn't already been tripped by something.

Try pressing the reset button to see whether that restores power to the outlet. If there is still no power, check the circuit breaker and reset it. If that didn't correct it, however, there's a good chance the GFCI is defective, then you will need to consult an electrician to replace it or find out what's wrong.

Step 2 - Test the Outlet

The GFCI outlet will have two buttons on it, normally these are color-coded. Press the test button on the front of the outlet and the power should immediately be switched off. Check that the lamp which is connected to the outlet has turned off. This works because the test button simulates a short circuit which will trip the circuit and stop any current being supplied.

If the power doesn't switch itself off and if the lamp doesn't turn off then the socket could be faulty or wired up incorrectly. You must contact an electrician to help sort this out, because at the moment it is doing nothing to protect you and your family.

Step 3 - Restore Power

Assuming the power has been cut properly then you can restore it again by pressing the reset button. This should reset the outlet and restore power. Check that the light comes on properly. If the GFCI outlet keeps on tripping continuously then this could be due to a defective outlet or to a wiring fault that will need the attention of an electrician.