Using a voltage tester, also known as a plug tester, on wall outlets and cords is an important way to check for dangerous voltage problems that could lead to electrocution or electrical fires. A voltage tester is a simple, inexpensive tool that allows you to quickly and safely determine if an outlet or cord is properly wired and free of voltage faults. Knowing how to properly use a voltage tester can help protect you, your family, and your home.
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What is a Voltage Tester?
A voltage tester, sometimes called a plug tester, outlet tester, receptacle tester, or line tester, is a small device used to detect electrical voltage in cords and wall outlets to check for wiring problems. There are two main types of testers:
Neon testers – These very basic testers have one or more neon bulbs that light up when voltage is detected. They confirm there is power but don’t provide any details about wiring problems.
Digital multimeter testers – More advanced digital testers have an LCD screen that displays details about the voltage being received and indicates specific wiring faults like reversed hot and neutral, missing ground, or crossed hot.
Why Use a Voltage Tester?
There are a few important reasons to use a voltage tester on your electrical outlets and cords:
- Detect voltage – Confirm power is flowing properly through cords and outlets.
- Identify wiring faults – Find potentially dangerous incorrect wiring that could lead to electrocution or electrical fire.
- Troubleshoot problems – Determine why an outlet is not working properly.
- Safety check – Verify grounding and polarity before using an electrical device.
- Prevent electrical damage – Catch wiring issues before they damage electronics and appliances.
Testing plugs and outlets with a voltage tester is a fast and easy way to diagnose electrical issues before they become larger safety problems.
How to Use a Voltage Tester on a Plug
Using a voltage tester on a plug involves very simple steps. Here is how to properly use a voltage tester on a plug:
- Turn off and unplug the cord you want to test from any outlet or device.
- Plug the cord into the electrical outlet you want to test.
- Plug the voltage tester into the other end of the cord.
- Turn on the outlet if it has a switch.
- Check the voltage tester for light or display readings. Refer to the user guide if needed.
- Make note of any displays or warnings indicating wiring faults.
- Unplug and switch off power when finished testing.
The voltage tester display will indicate if the outlet is properly wired or if there are any faults with the hot, neutral, or ground wires.
How to Interpret Voltage Tester Results
The meaning of voltage tester results will vary slightly depending on whether you have a basic neon tester or digital multimeter display. Here is how to interpret the results:
Neon testers
- No light – No power is flowing. Check breakers and wiring.
- Solid light – Power is flowing properly.
- Flickering light – Wiring fault likely. Further investigation needed.
Digital multimeter testers
- Digital display of voltage – Power is flowing properly.
- “Correct” or solid/lighted neutral and ground indicators – Wiring is correct.
- “Hot/Neutral Reverse” warning – The hot and neutral wires are flipped.
- No ground indicator – No ground wire detected.
- “Hot/Ground Reverse” – The hot and ground wires are reversed.
- “Open hot” – Hot wire is disconnected.
- “Open neutral” – Neutral wire is disconnected.
- “Open ground” – Ground wire is disconnected.
- “Hot and neutral crossed” – Hot and neutral wires reversed somewhere.
Any reversed wire or open wire warning indicates a serious safety issue that should be repaired immediately by an electrician.
Safety Tips When Using a Voltage Tester
Voltage testers are very safe devices, but you should keep these electrical safety guidelines in mind when using one:
- Unplug cords before testing.
- Don’t use if you have wet hands or if tester is wet.
- Turn power off and on only by the wall switch, not by unplugging.
- Never put tester contacts into the hot slots of an outlet.
- Keep children away when testing outlets.
- Only change electrical wiring if you are a qualified electrician.
- Replace any damaged electrical cords or testers.
Following basic electrical safety helps prevent shocks, electrocution, and other injuries when testing outlets and plugs.
Troubleshooting No Voltage Tester Reading
If your voltage tester is not displaying any results or lights, here are some steps to troubleshoot:
- Plug tester into a known good, working outlet to verify tester is operating correctly.
- Try different outlets in case just one outlet is no longer working.
- Reset or replace any tripped breakers supplying the outlet.
- Verify outlet is actually switched on.
- Try unplugging everything on the circuit then testing.
- Inspect all wiring connections on outlet for loose, disconnected, or damaged wires.
- Test wiring continuity with a multimeter if available.
- Call an electrician if wiring appears damaged or incorrectly connected.
A blank voltage tester that worked previously likely indicates an underlying electrical wiring problem needs to be addressed in the outlet or circuit panel.
Conclusion
Voltage testers provide a fast and easy way to check for proper voltage and catch potentially hazardous wiring problems in electrical cords and outlets. By understanding when to use a tester, how to properly operate one, and how to interpret the results, you can quickly diagnose and address electrical faults before damage or injuries occur. With the safety of your home and family in mind, every home should keep a basic voltage tester and use it regularly as part of routine electrical safety maintenance.
Frequently Asked Questions
What are the signs of a faulty electrical outlet?
Some signs of a faulty electrical outlet include:
- Frequently tripped circuit breakers
- Burning smell from the outlet
- Discolored outlet faceplate
- Cracked, damaged, or warm outlet cover
- Tingling feeling when plugging in a cord
- Lights flickering when using the outlet
- Loose outlet components
- Frequent shocks from the outlet
Can I get electrocuted from a voltage tester?
Properly using a voltage tester is very safe and you cannot get electrocuted from the testing probes. Just be sure to keep your hands dry, firmly insert the tester in the socket, only test plugs that have been unplugged, and only turn power on or off from the wall switch. As long as you use it according to the instructions, a voltage tester is a safe way to check for electricity.
What are some of the best voltage testers?
Some top-rated voltage tester models include:
- Klein Tools ET310
- Fluke 1AC-A1 II VoltAlert
- Ideal 61-035 Power Outlet Tester
- Klein Tools RT105
- Milwaukee 2277-20
- Amprobe ST-102B Outlet Tester
Look for testers that are UL listed and have automatic circuit shut off for safety. The best testers also include clear LCD displays explaining the detected wiring fault.
Should I test every outlet in my home?
It’s a good practice to periodically test a sample of outlets in your home to catch any potential wiring issues, especially outlets that are loose, damaged, or frequently used. However, you don’t necessarily need to check every single one. Test a variety in kitchens, bathrooms, bedrooms, and especially any outlets near water sources. Also test exterior outlets and those connected to major appliances.
What should I do if the voltage tester detects a wiring problem?
Any outlets where the voltage tester finds a wiring fault should immediately be switched off at the breaker panel. Do not use the outlet until it can be repaired or replaced by a qualified electrician. Severe faults like reversed wires indicate incorrect and dangerous wiring that poses a safety hazard if used.