A GFCI outlet tester is an important tool for homeowners and electricians to check that ground fault circuit interrupter (GFCI) outlets are working properly. GFCI outlets help prevent electric shocks by shutting off electricity when a ground fault is detected. Using a GFCI outlet tester is a quick and easy way to make sure your GFCIs provide protection.
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What is a GFCI outlet?
GFCI outlets monitor electricity flowing in a circuit and detect any imbalance between the hot and neutral wires. This imbalance is sometimes called a “ground fault” and can result from damaged wires, shorts, or current leaking through a person’s body to ground. When a ground fault is detected, the GFCI cuts off power within a fraction of a second to prevent electrocution.
GFCIs are now required in bathrooms, kitchens, laundry rooms, basements, garages, pool areas, and many outdoor outlets. Older homes may need GFCI outlets added to become compliant with modern electrical codes.
Types of GFCI outlets
There are two main types of GFCI outlets:
- GFCI receptacles – Replace a standard outlet with a GFCI outlet for protection at that location.
- GFCI breakers – Install at the breaker box to protect all outlets on the circuit.
Why test GFCI outlets?
Testing GFCIs is important for several reasons:
- Make sure new GFCI installations are working properly.
- Periodically check that GFCIs have not been damaged and are providing protection.
- Diagnose why an outlet has lost power.
- Ensure GFCIs can trip when a ground fault occurs.
- Verify that the TEST and RESET buttons function correctly.
The National Electrical Code requires that GFCIs be tested after installation and at least once a month thereafter. More frequent testing is a good idea in damp or dangerous locations.
How a GFCI outlet tester works
A GFCI outlet tester is a device with three prongs that plug into an outlet like an ordinary plug. Indicator lights on the device report details about the type of outlet and its status.
The tester checks for:
- Correct wiring: It verifies the hot, neutral, and ground connections are hooked up properly.
- GFCI protection: It detects if the outlet is on a GFCI-protected circuit.
- GFCI functionality: It tests whether the GFCI can trip when a ground fault is simulated.
This information helps identify wiring errors and malfunctioning GFCIs that could leave users vulnerable to shocks.
How to use a GFCI outlet tester
Using a GFCI outlet tester is very simple. Just follow these steps:
- Plug the tester into the outlet and observe the indicator lights.
- Check that the wiring is correct.
- Press the “TEST” button to trip the GFCI.
- The reset button may need to be pressed to reset the GFCI and power on the outlet again.
- Repeat steps for each outlet.
Here are more details on the process:
1. Plug in the GFCI outlet tester
Insert the device into the outlet slots just like an appliance plug. The tester does not need to be grounded to work properly. The lights may initially all be off if the outlet is not powered.
2. Check for proper wiring
There will be three indicator lights labeled “correct”, “open ground”, “hot/ground reversed”, or similar. The meanings are:
- “Correct” = The outlet is wired correctly with separate hot, neutral, and ground connections.
- “Open ground” = No ground wire is connected to the outlet.
- “Hot/ground reversed” = The hot and ground wires are reversed in the outlet.
For safe operation, the “correct” light should be lit. The other lights indicate improper wiring that needs to be fixed. An open ground may make the GFCI function intermittently.
There will be a “TEST” button on the GFCI outlet tester. Press and hold this button down.
If the outlet is on a functioning GFCI circuit, pressing TEST will break the circuit and shut off power to the outlet. This proves the GFCI is working.
You may hear an audible click from the outlet when the TEST button is pressed as the contacts open. The indicator lights can verify the power is off.
If pressing TEST does not trip the GFCI, then the outlet is likely on an unprotected circuit.
GFCI outlets have a RESET button that reconnects power after testing. The GFCI needs to be reset before the outlet will work again.
Check for a RESET button on the tester or outlet. Press it to restore power so you can safely unplug the tester.
If an outlet doesn’t reset, then the GFCI may be faulty and the circuit will need repair.
5. Repeat for each outlet
You need to test every GFCI outlet to make sure each one provides protection. Repeat the steps above for every outlet, one at a time.
It’s a good idea to test bathrooms first since they have lots of water risk. Also test outdoor outlets which get exposed to moisture.
If you have any outlet that fails the test, call an electrician to inspect and fix the issue.
What do the indicator lights mean?
Here is an explanation of the common indicator lights on a GFCI outlet tester and what they indicate:
Power Light
The “power” or “hot” light shows that the outlet has electricity flowing to it and is powered on.
- On = Electricity detected
- Off = No power to the outlet
GFCI Protected Light
This indicates if the outlet is on a circuit protected by a functioning GFCI. It should activate when the TEST button is pushed.
- On = GFCI protection present
- Off = No GFCI protection
Open Ground Light
An open ground means the ground wire is not properly connected to the outlet.
- On = Open ground detected
- Off = Good ground connection
Hot and Ground Reversed
This light indicates the hot and ground wires are reversed in the outlet box.
- On = Wiring error
- Off = Wires connected properly
Correct Wiring Light
This indicates that the hot, neutral, and ground wires are connected correctly to the outlet.
- On = Wiring is correct
- Off = Incorrect wiring
What if the GFCI won’t reset?
If a GFCI outlet won’t reset after testing, there are a few possible causes:
- Faulty wiring – May need an electrician to troubleshoot and repair.
- Moisture got into the GFCI – Allow it to dry out thoroughly.
- Bad GFCI – Replace the GFCI outlet if it is old or damaged.
- Tripped breaker – Check the breaker box for a tripped GFCI breaker.
- Multiple GFCIs – Make sure all GFCIs on the circuit are reset, even in remote locations.
Try pressing the RESET button firmly and holding for 10+ seconds. If it still won’t reset, contact an electrician to investigate.
GFCI outlet tester tips
Follow these tips when using a GFCI tester:
- Plug into outlets before turning any lights or appliances on. This provides a clean test.
- Double check the indicator lights – verify the outlet is labeled correctly.
- Try out the tester on a known working GFCI first to learn how it works.
- Reset GFCIs immediately after testing so they are armed and ready to protect.
- Some testers have an audible alarm that sounds when the GFCI trips.
- If you have outlets in remote areas like garages, make sure you test them.
- Test outdoor outlets which are prone to moisture damage.
- Don’t use if there are any cracked, scorched or broken areas on the tester.
How often to test GFCI outlets
The National Electrical Code requires testing GFCIs at installation and once per month thereafter. However, you may want to test more frequently in certain circumstances:
- High-risk areas: Test every week in bathrooms, kitchens, laundry rooms, etc.
- Outdoor outlets: Every 2 weeks for decks, patios, pool equipment.
- Rarely used outlets: Test before each use in basements, garages, sheds.
- After electrical work: Test immediately after any electrical repairs or wiring changes.
- Following repairs: Test after plumbing, flooding, or ground shifting that may affect wiring.
- Older homes: Test more often in older houses with aging wiring.
Mark your GFCI testing schedule on your calendar so it becomes a regular maintenance routine.
Can you use an outlet tester on a GFCI?
Yes, standard 3-light outlet testers work well for testing GFCIs. Look for testers clearly labeled as compatible with both standard and GFCI outlets.
A GFCI outlet tester has the added TEST and RESET buttons to check the GFCI’s protection. The indicator lights verify hot/neutral/ground wiring and show if pressing TEST successfully interrupts electricity.
Conclusion
Testing GFCI outlets takes just a minute and is essential to verify this important safety device works properly. Use a dedicated GFCI tester and follow the steps to check wiring, trip the circuit, and reset it.
Look for indicator lights signaling “correct” wiring, GFCI protection present, and successful tripping when you hit the TEST button. If anything seems amiss, hire an electrician to investigate and fix issues.
Test all GFCI outlets in your home monthly or more often in high-risk areas. This provides peace of mind that your electrical system is safe and works as intended to prevent shocks.