You may have noticed that some of the outlets in your kitchen, bathroom or garage look different from the other outlets in your house. These outlets are shaped differently and have two small buttons in the center. Those special outlets are called ground-fault circuit interrupter or GFCI outlets. They are also known as GFI or ground-fault interrupter outlets. In this article, we’ll explain exactly what a GFCI is and how it works. Finally, we’ll examine some of the problems that might be causing your GFCI to shut off or “trip.”
Please know that for your safety, it’s best to call a professional when dealing with electrical issues. We do not advise doing these repairs yourself without understanding the risks.
What is a GFCI Outlet?
A GFCI outlet is wired directly into your home’s electrical circuits and is designed to monitor the current flowing through the circuit. Any interruption or surge that alters the current (such as dropping a hair dryer in water or plugging too many appliances into one circuit) will cause the GFCI to shut off or “trip.” By shutting off the electrical current, the GFCI protects you from electrical shocks and prevents fires caused by overheated circuits. Most states require the installation of GFCIs in areas near water sources, such as kitchens and bathrooms, as well as in all outdoor receptacles.
What Causes a GFCI Outlet to Trip?
Typically, the GFCI outlets in your home are wired in such a way that only a major electrical problem will cause them to trip. However, there are a few instances in which a GFCI will keep tripping regardless of what is plugged into it. If this is happening, that means there is an underlying problem that needs to be addressed immediately. A GFCI that is continually tripping is not working properly and exposes you and your home to the risk of electrical shock or fire from an overloaded circuit.
How Does a GFCI Outlet Work?
When an electrical current escapes or “leaks” out of its proper path, it is called a ground fault or leakage current. A GFCI outlet is designed to trip about one tenth of a second after it detects even a tiny amount of leaking current. Because the circuit that is being protected by the GFCI can span multiple rooms and have multiple appliances running on the same circuit, it can be difficult to determine the cause of a tripped GFCI, especially when nothing is plugged into it or it seems to trip at random times. These “ghost trips” are most often caused by:
- A ground fault somewhere in the circuit.
- Moisture invading the receptacle box.
- A faulty GFCI outlet.
The next section will explain each of these causes in more detail and show you how to fix the problem.
Fixing a Ground Fault in the Circuit
If you’ve reset a tripped GFCI but it keeps tripping when you plug appliances back in, then there is a ground fault or leakage current somewhere in the circuit. Until the ground fault is fixed, the GFCI will continue to trip.
To determine where the current is leaking:
1. Unplug all the appliances that are on that outlet’s circuit.
2. Push the reset button on the GFCI.
3. Plug in one appliance at a time until the GFCI trips. The last appliance you plug in/turn on is likely the source of the leakage or all of your appliances in combination are overloading the circuit. You can double check this by unplugging all the appliances that were on before the GFCI tripped, except for the last one you plugged in. If the GFCI still trips, you’ve found the source of the ground fault.
4. Replace or repair the faulty appliance.
Fixing Moisture Inside the Receptacle Box
If the problem GFCI is an outdoor receptacle or an indoor outlet that was exposed to water in some way, moisture inside the receptacle box could be causing the GFCI to trip. A wet GFCI will trip regardless of what is plugged into it and may continue to trip even if there is no visible moisture inside the box. Trapped moisture inside the box will cause the GFCI to trip until it dries up.
What to Do if There’s Moisture Inside the Receptacle Box:
1. Reset the GFCI outlet. You may have to wait several hours for the moisture inside the receptacle to dry. Removing the cover and using a hair dryer set on low to blow warm air into the box can help speed up this process.
2. Once you’ve reset the GFCI outlet, make sure you have a protective receptacle covering as required by the National Electric Code. When choosing a protective covering, make sure that the label lists the following:
- Extra duty
Note: Always make sure your weatherproof covering is closed over outdoor receptacles whether there are appliances plugged in or not.
Faulty GFCI Outlet
If you have a GFCI that won’t reset even if nothing is plugged into the circuit, you either have an issue with another outlet on that circuit or a faulty GFCI. Since a single circuit can span multiple rooms, there are likely multiple outlets wired into it and a problem in any one of them can cause the GFCI to trip. The other possible explanation is that the GFCI itself is faulty. A GFCI uses sensitive circuitry to detect ground faults and over time, this circuitry can become worn out. In this situation, the only solution is to replace the GFCI.
Both of these issues are major electrical repairs and you should call an electrician if you suspect that either of these is the source of your GFCI problems.
Every year, hundreds of Americans die from electrical shocks. In a typical 120 volt outlet, 2 seconds of exposure to a ground fault or electrical surge is enough to kill an adult. GFCIs are specifically designed to protect you and your family from the devastating effects of electrical shocks or fires; that is, if they are working properly. Make sure to test your GFCIs monthly and if you notice one that is not working as it should, call a professional electrician immediately.