The research
- Why you should trust us
- Who this is for
- How we picked and tested
- Our pick: Klein NCVT-3
- Flaws but not dealbreakers
- Runner-up: Milwaukee 2203-20 Voltage Detector with LED
- The competition
- Footnotes
Why you should trust us
I’ve been writing about and reviewing tools since 2007, with articles appearing in Fine Homebuilding, This Old House, Popular Science, Popular Mechanics, and Tools of the Trade. I also spent 10 years in the trades as a carpenter, foreman, and job site supervisor working on multimillion-dollar residential projects. In 2011, I also gutted my 100-year-old farmhouse, which required a whole new electrical system.
For more information on non-contact voltage testers, I spoke with someone who uses them every day: Mark Tierney of Tierney Electrical out of Hopkinton, Massachusetts. Tierney has 20 years of experience and has run his own company since 2010.
Who this is for
A non-contact voltage tester detects electricity in a wire or outlet, just by getting near it.1 It is the size and shape of a fat Sharpie and the detection occurs at the probe tip, which, in many cases, is designed to be pushed into an outlet. Because electrical shocks are unpleasant at best and extremely harmful at worst, this tool is useful for even the lightest electrical work, like troubleshooting a thermostat or installing a dimmer switch.
Obviously, it’s a good tool for the DIY electrician, but even someone with zero electrical inclination can benefit from owning one. I commonly use one as the first stage of troubleshooting before calling a professional electrician.
A non-contact tester can also help map out your existing electrical system. I have yet to live in a house that has had anything close to a properly labeled panel, and if you have an old house or apartment, there is a strong chance that your electrical panel is mislabeled as well. It’s a time-consuming process to sort this out, but it’s possible. Shut down all of the breakers but one, then go around the house checking to see what’s live. Once you figure that out, label the breaker, and move on to the next one.
How we picked and tested
Most non-contact testers register only standard voltage. After reading what we could on the subject, we decided that a dual-range voltage tester would be better for the home toolbox. It still works the same for standard voltage, and there is the added benefit of low-voltage detection, which is useful for doorbells, thermostats, some AV equipment, irrigation, and some landscape lighting. Both dual- and single-voltage models fall primarily in the $15 to $25 range, so a dual-range unit makes sense as a one-stop tool for the non-specialist; it’s better to have the capability and not use it, than to need it and not have it.
In deciding which models to test, we researched units at Amazon, Home Depot, and Lowes. We also keyed in on reputable manufacturers of electrical tools. From that, we narrowed our list down to seven.
We ran a few tests to determine the overall usefulness and sensitivity of each tester. First, I shut off a single breaker at my electrical box and tried to discover which of the 35 wires coming out of it was the dead one. After that, I took a dead wire and saw how close I could get the tool to a live wire and still have the tester read negative. In addition to those structured tests, I used the testers as I wired some outlets, and installed some dimmer switches, a cooktop, a ceiling fan, and a few pendant lights.
Our pick: Klein NCVT-3
Our pick
Klein NCVT-3
The Klein detects standard and low voltage and is equipped with a handy flashlight—a nice touch for a tool you may need when the lights go out.
Buying Options
$16 from Home Depot
*At the time of publishing, the price was $24.
After researching the topic, talking to an electrician, and spending hours testing seven leading models, we recommend the Klein NCVT-3. The NCVT-3 has a very intuitive indicator light, a nice on/off button, and an onboard LED that works like a little flashlight. This is a great feature, seeing as the lights may not be working too well when you’re checking wires for voltage. It is also compatible with tamper-resistant outlets, now required by code. The NCVT-3 has a battery life indicator and a durable body that protects its sensitive electronics from a fall of up to 6½ feet.
Most of all, the NCVT-3 is very easy to use. It’s a dual-range unit, so it can detect standard voltage (outlets, regular wiring) as well as low voltage (doorbells, thermostats, irrigation wiring). Most testers detect only standard voltage. Unlike most other dual-range models, it switches between the ranges automatically without the use of a fussy sensitivity dial. An LED bar graph at the side of the tool indicates which voltage you’re dealing with. A low voltage detection lights up the lower two orange lights and standard voltage lights up one or more of the upper three red lights. Many companies sell separate high- and low-voltage detectors, but for the non-specialist, it makes sense to have them in a single tool, particularly if it works as easily as the Klein.
The LED flashlight is a high point of the NCVT-3. In my own basement, the wires are stapled to the ceiling above the fluorescent lights, so even with the lights on, it’s hard to work with the wires. Of the two models with an onboard flashlight, the NCVT-3’s is the only one that can be operated independently from the testing function, which is really nice. When the tester is activated, a series of beeps and blinking lights occur and it’s nice to be able to sidestep that if you’re just trying to use the flashlight. Our runner-up selection, the Milwaukee 2203-20 Voltage Detector with LED also has a flashlight function, but it comes on only when the tester is activated, so no matter what, you have to listen to the beeps and there is no way to shut the flashlight off, even if you’re working in a well-lit room. The NCVT-3 LED is also brighter than the Milwaukee.
The NCVT-3 also has a very durable feel to it. According to the manufacturer, it can withstand a fall of 6½ feet, so if you get a case of the dropsies, this model will give you a shot at survival. In addition, the buttons are all sealed and the cap of the battery compartment is gasketed, so the NCVT-3 can handle a little rain and dampness. Klein has a video of the tool where it looks like it’s under a steadily dripping faucet.
When we asked electrician Mark Tierney if there were any manufacturers he would recommend to a homeowner, he told us that the “the one that has been the most reliable is the Klein.” He also likes the models that come with the LEDs, saying that for a homeowner, “they would get two great features in one tool.”
For battery life, Klein says that the two AAA batteries will provide 15 hours of continuous tester use and six hours of continuous flashlight use. This is plenty for the occasional user, and like we said, it’s nice that there is a battery indicator light, so that you’ll know when it is getting low.
And we’re not the only ones that like the NCVT-3. Clint DeBoer, writing at ProToolReviews, says that the tool “is as close to a no-brainer as you can get if you even occasionally do electrical work.” He concludes his review with, “This is a well-designed tool that does what it’s supposed to and does it well. Pick one up. You won’t regret it.”
The NCVT-3 also gets generally positive owner reviews at Amazon and Home Depot. Most of the negatives at Amazon are from people who like the tool but are disappointed that it cannot be inserted into an outlet. As we described above, this is not an issue because it can still detect the current, only displaying it as low voltage (and making it compatible with code-required tamper-resistant outlets). To truly confirm standard voltage on an outlet, it’s easy enough to unscrew the cover plate and place the tip of the tool at the side of the outlet where the wires are.
Flaws but not dealbreakers
The NCVT-3 is unique because it cannot be inserted into an outlet. At first glance, this may seem like a problem, seeing as most other non-contact testers read power from an outlet only by being inserted into one of the openings. The reality is that because it can read low voltage, the NCVT-3 can still pick up the current from the outside of the outlet, which is essential when dealing with the tamper-resistant outletsnow required by electrical code. To insert a plug in one of these outlets requires equal pressure on both prong openings (it’s a safety issue for children). With these outlets, a traditional non-contact voltage tester doesn’t always work because it can read only standard voltage. As Bruce Kuhn, Klein’s director of product development, test and measurements products, told us, “If you make a tester like this sensitive enough to detect voltage on the ‘outside’ of a tamper-resistant outlet, it will be too sensitive in a crowded electrical box that contains several hot wires.”2 Because the NCVT-3 is designed to detect standard and low voltage, it picks up the standard voltage when placed at the openings of a live tamper-resistant outlet, but from a distance, displaying it as low voltage, still confirming that the outlet is live.
The NCVT-3 has the control buttons on the side, which is something Tierney told us to watch for. He warned that models with a side button easily turn on when they’re in a pocket, which is not only annoying, but also speeds up battery drain. One redeeming difference with the NCVT-3 is that the buttons are flush with the surface; most buttons like this stick out from the side of the tool and it’s easy for them to accidentally be activated. I spent a day with the NCVT-3 in my pocket, and it didn’t turn on once.
The NCVT-3 also has no mute option, but it’s quieter than other testers we looked at.
Runner-up: Milwaukee 2203-20 Voltage Detector with LED
Also great
Milwaukee 2203-20 10-1000V Dual Range Voltage Detector
Runner-up
This dual-voltage tester is similar to our pick in the most important ways, but some of its minor details are a bit more annoying.
Buying Options
*At the time of publishing, the price was $25.
If the Klein is not available, we recommend the Milwaukee 2203-20 Voltage Detector with LED. It has many of the same features as the Klein NCVT-3, but the flashlight isn’t as bright and can’t be used independently of the tester. It also makes an incredibly loud beep (no mute option). This could be beneficial on a noisy job site, but after I spent 45 minutes checking wires in my basement, the volume was enough to drive me a little nutty.
Still, the Milwaukee can detect the low and standard voltage, and there is no manual toggle between them, so it’s as simple to use as the NCVT-3.
The competition
In 2019, we noticed that Klein now has the NCVT-4IR. It looks to be the same as our pick, but also includes an infrared thermometer function. We don’t feel this is worth the added cost for regular home use.
We also noticed models from companies like Meterk, ToHayie, Taiss, and SOCLL. These are generic tools from little-known companies. We feel much safer recommending a tester from a proven manufacturer of electrical diagnostic equipment.
We tested the Klein NCVT-2, which is very similar to the NCVT-3. It’s also a dual-range model that automatically detects between the two ranges, but it doesn’t have the LED; the on/off button is proud of the case (so it is likely to turn on in a pocket); and the case doesn’t have as durable a feel.
The Greenlee GT-16and Sperry VD6505, which we also looked at, use a dial to select the sensitivity between low and standard voltage. During our testing, we found that when there were multiple wires in the area, those models would pick up the signal from other wires, making it difficult to know when we had the sensitivity dialed down enough to detect only the wire we wanted. It was tough to get the hang of the sensitivity dial and much preferred the simpler interface of the Milwaukee and Kleins.
The Greenlee TR-12Ahas a two-prong design, made specifically for use with tamper-resistant outlets, but it reads only standard voltage and not low voltage, so we feel the NCVT-3 is more useful.
The Klein NCVT-1detects only standard voltage. I’ve owned one for years and have always found it to be accurate and reliable, but it makes sense to get a model that can detect low voltage as well.
Footnotes
FAQs
How reliable are non contact voltage testers? ›
These devices are not 100% accurate, but they do a pretty good job. You simply hold the tip near a suspected circuit, and it'll tell you if there's current or not.
How do you test non contact voltage? ›To use a non-contact voltage tester you only need to touch the tip of the tester to the wire or, if you're testing an outlet, the tip of the tester needs to be placed on the faceplate of a smaller plug slot. Most testers will light up and/or make a sound to confirm voltage is present.
Can you test DC voltage non contact? ›Test quickly for energized circuits, detect AC and DC voltages with non-contact volt detectors available from Specialized Products. They are safe and allow you to avoid exposure to high voltage electrical shock or personal injury.
What is the most accurate device for measuring voltage? ›Multimeter Method
A common piece of test equipment is multimeter. The multimeter contains circuitry that allows it to be used as a voltmeter, an ammeter, or an ohmmeter. It is usually capable of measuring both AC and DC voltages of up to several hundred volts.
One of the easiest ways to know if a wire is live is to use a voltage checker or a current checker. These are simple devices that you can touch to any wire, and it will tell you if there is electricity running through it.
Can a non-contact voltage tester work through drywall? ›A: Yes. The instrument has two detection levels, one for low voltage and one for house voltage and above. If you want to check for wires behind walls, switch the instrument to low voltage detection mode.
Can a non-contact voltage tester give a false positive? ›Now that you have a better understanding of capacitors and how non-contact voltage testers work, it's important to understand that they can provide false positive results sometimes.
What are the three test instruments that can be used to verify no voltage is present in a de energized circuit before beginning work? ›If testing for the absence of voltage, that is, to verify there is no voltage present before beginning work, consider using a noncontact proximity tester (Figure 1), an electrical tester (Figure 2), or a multimeter (Figure 3).
How do you make a non-contact AC voltage detector? ›Building Your Own Non-contact AC Voltage Detector
Mount the components on the PCB and solder them one by one in the appropriate places as per the circuit diagram. Connect one terminal of the copper wire and to the base of the first transistor. The copper wire will act as an antenna.
A non-contact voltage detector is a device that can detect the presence or an electrical charge in a wire, cable, or piece of equipment without having to touch the object. Voltage detectors are primarily used by electricians and electrical technicians.
Do voltage testers work on DC? ›
The testers cannot work with DC voltages since the capacitors and transformers do not work with DC. The non contact voltage testers have limitations and do not actually measure the amount of voltage present.
Which is better fluke or Megger? ›The Megger MIT525 has a larger resistance range than the Fluke 1550C as well as better enclosure sealing, a better battery, larger internal memory, and greater test voltage accuracy.
What are the three types of tester? ›- Unit tests. Unit tests are very low level and close to the source of an application. ...
- Integration tests. ...
- Functional tests. ...
- End-to-end tests. ...
- Acceptance testing. ...
- Performance testing. ...
- Smoke testing.
- Best Value. Hillgrove Electrical Non Contact Voltage Detector/Teste... 3.9. (703) ₹239. ₹499. ...
- Inditrust Heavy Duty Three type Electric Tester 1pc Vol... 3.7. (1,095) ₹299. ₹600.
- ELEKTRON'S BLT 700 Digital Battery Tester. 4.2. (90) ₹7,499. ₹8,999. 16% off.
- KONVIO Non Contact Pen type Digital Voltage Tester. 3.9. (32) ₹349. ₹999.
Hence the correct answer is Rectifier meter has the highest accuracy in the prescribed limit of the frequency range.
What is better than a voltmeter? ›If you need to measure voltage, then you a voltmeter is sufficient, but if you want to measure voltage and other things such as resistance and current, then you are going to have to go with a multimeter.
Which type of multimeter is more accurate? ›The digital multimeter can be used to test various electronic components such as diodes, transistors, capacitors as well as measuring basic electrical quantities. Digital multimeters measure more accurately than analog multimeters.
Can you touch positive wire without getting shocked? ›You will receive a shock if you touch a live wire and are grounded at the same time. When a circuit, electrical component, or equipment is energized, a potential shock hazard is present.
What happens if live wire touches neutral? ›When live wire comes in contact with the neutral wire, then the insulation of wires is damaged or there is a fault in the appliance. In such a situation, the current in the circuit abruptly increases. This is known as short circuiting.
What happens if you touch 2 live wires? ›If you touch both cables at the same time, then your body becomes a conductor and the current of electricity will pass through your body. Also, if you touch a cable that has current flow and also touch an electric connection that is grounded, then you become the easiest path for electricity to go to the ground.
Is there a tool to detect wires in walls? ›
There are two kinds of stud finders that can help you find wires in a wall – magnetic and electric. A magnetic stud finder is used to detect metal nails in wall studs. Electronic stud finders produce a tiny electrical field that changes when the finder reaches a denser region in a wall.
Can a non contact voltage tester work through walls? ›They're called "non-contact", but that means no electrical contact (i.e. they don't have to touch the bare wire). You'll just about have to touch the tool to the insulation of a wire for them to work properly, so it's not likely you'll be detecting wiring within any type of wall with one of these tools.
How do I test a live wire in the wall? ›Use a quality cable detector.
A quality cable detector can help you to track buried cables before you start work and avoid the risk of an electric shock. If you dont have a detector a good tip is also to avoid any area horizontally or vertically from any switch or socket.
As you may know, ghost voltages occur when your test (which isn't receiving power) reads voltage from a nearby electrical source. Usually, this is due to extra and unused wiring in the conduit being tested as it runs along other wires that are receiving power.
Do voltage testers need calibration? ›The accuracy of electrical testing equipment can drop over time. To avoid safety issues or process failures, it is critical to ensure that any electrical testing equipment used within your business is regularly calibrated.
Which detector is specifically designed to ensure the absence of voltage? ›Make no mistake, the Absence of Voltage Tester (AVT) is a relatively new innovation. Unlike traditional voltage testers, the AVT is not portable and is installed in the equipment it is testing.
Which instrument can be used to measure unknown voltage? ›A potentiometer is an instrument for measuring voltage or 'potential difference' by comparison of an unknown voltage with a known reference voltage.
What device is specifically used to measure only voltage? ›voltmeter, instrument that measures voltages of either direct or alternating electric current on a scale usually graduated in volts, millivolts (0.001 volt), or kilovolts (1,000 volts). Many voltmeters are digital, giving readings as numerical displays.
How does a wireless AC detector work? ›The radiated AC line signals are received by this antenna. These signals are then amplified and fed to the LED blink circuit section. Hence when the LED starts blinking the person testing the wire can know that the wire is Live and hence should be played safe with!
What is an NCV detector? ›Built-in Non-Contact Voltage (NCV) Detector allows for quick detection of live voltage. Convenient LED flashlight illuminates dimly lit area.
What is the difference between Fluke 1AC and 2ac? ›
A: The 2ac is the newer model with an "always on" function. It has a button that is used only to ensure that it still has battery power. The 1ac is the older one that can be turned on or off. They both test for voltage presence the same way, but the 1ac has an audible alert function which the 2ac does not have.
How do you use a Fluke non-contact voltage tester? ›The portable 1AC II non-contact voltage tester from Fluke are easy to use – just touch the tip to a terminal strip, outlet, or supply cord. When the tip glows red and the unit beeps, you know there's voltage present.
How do you test non-contact voltage? ›To use a non-contact voltage tester you only need to touch the tip of the tester to the wire or, if you're testing an outlet, the tip of the tester needs to be placed on the faceplate of a smaller plug slot. Most testers will light up and/or make a sound to confirm voltage is present.
Can I use a multimeter as a voltage tester? ›Use a multimeter it to check the following electricity-related properties: AC voltage: Tested in items with electrical plugs. DC voltage: Tested in batteries or other items that hold a bank of electric power. Resistance: Measured in ohms.
What happens if you test AC with DC multimeter? ›AC will display as zero voltage on a DC setting, regardless of the polarity. Reversing the leads and still reading zero will distinguish this from DC with reversed polarity if the meter displays zero for reversed polarity DC.
Will a voltage tester work on low voltage? ›Most of all, the NCVT-3 is very easy to use. It's a dual-range unit, so it can detect standard voltage (outlets, regular wiring) as well as low voltage (doorbells, thermostats, irrigation wiring). Most testers detect only standard voltage.
Can you get a shock from ghost voltage? ›Since the “phantom” voltage is a physical phenomenon involving very small values of capacitance, it cannot energize a load or cause physiological damage to a person.
How many volts is phantom power typically? ›Alternatively (and most commonly) the DC power is provided by the pre-amp/mixer and delivered to the condenser microphone via the mic cable. This method is referred to as phantom power. The worldwide standard for phantom power is 11 to 52 volts of DC (typical studio mics run on 48v).
What is the common voltage for phantom power? ›Popular phantom voltages are 12 V, 15 V, 18 V, 24 V, and 48 V. 48 volt phantom is the most common and many microphones require 48 V for proper operation.
How do you choose a good voltmeter? ›Specifications: Accuracy and measuring range are the two main parameters to consider when buying a voltmeter (in both control panel and plug-in meters). However, if users are looking for a unit that can measure different parameters, such as current, voltage, and resistance, digital multimeters should be considered.
What's a good brand of multimeter? ›
As to the best multimeter brands, Fluke is the market leader and we have always gone with them, but some of the mid-level multimeter brands like Brymen and Amprobe also make solid devices.
Which multimeter is best for home use? ›Which multimeter is best for beginners? In our opinion, the Fluke 107 AC/DC Current Handheld Digital Multimeter is the best multimeter for beginners, as it's easy to use and has most of the functions a DIYer will need.
Should I get a voltage tester or multimeter? ›If you need to measure voltage, then you a voltmeter is sufficient, but if you want to measure voltage and other things such as resistance and current, then you are going to have to go with a multimeter. The most significant difference in both devices is going to be whether you buy a digital or analog version.
How much should I pay for a multimeter? ›Step 2: How Much Should You Spend on a Multimeter? My recommendation is to spend anywhere around $40~$50 or if you can maximum $80 not more than that. Now don't get me wrong for some people even $40 is also too much but trust me it will be worth it here is the reason.
What are two important things to remember about the voltmeter? ›The most important thing to remember is that the voltmeter should be connected in parallel with the light bulb. That means you can always connect the voltmeter last. You do not have to disconnect any circuit elements in order to properly add a voltmeter to a circuit.
Which is better analog or digital multimeter? ›Conclusion. Overall, digital multimeters are much easier to read and provide more accurate readings. These days many analog multimeters are a thing of the past, and many professionals choose to use digital multimeters.
Are cheap multimeters any good? ›The cheap meters are certainly good enough, even though you do get what you pay for, as you might expect. As long as you have a meter open, you might as well hack it to have WiFi. Or, if you prefer, a serial port.
Are Klein multimeters as good as Fluke? ›This is a difficult decision, but fortunately, both brands offer great features and performance. Fluke multimeters are renowned for their high accuracy and reliability, while Klein's models boast low prices and good overall performance.
Is Fluke worth the money? ›Fluke is for professional, if you look at the specs it is more accurate and over wider temperature. If you look inside, the Fluke will be made with more stable components keeping it higher accuracy longer. That's why it costs 10 times more. For most home users, buy the cheap meter, way more accurate than you will need.
What is the difference between CAT 3 and CAT 4 multimeters? ›CAT III is for distribution wiring, including main busses, feeders, and branch circuits with permanently installed loads. The highest is CAT IV, which is installation at the origin or at the utility level. Our devices are rated for 600V at CAT IV, for applications between 600 and 750V, they are CAT III rated.
What are the three types of multimeters? ›
There are different types of multimeters like Analog, Digital, and Fluke multimeters.
What should you not do with a multimeter? ›- Do not drop any meter.
- Do not overload any meter. ...
- Do not tamper with precision instruments. ...
- Before you connect a meter to a circuit, ensure that the range switch is set to an appropriate position.
- Carefully check circuit connections before applying power to meters.
That is there is a difference in potential of 12.6 volts between the batteries positive and negative terminals. Thus voltage, V is always measured across or in parallel with a circuit component.
Do electrical engineers use multimeter? ›Arguably the most indispensable tool in an electrical engineer's arsenal is a multimeter. Besides measuring voltage and current, a multimeter can also help you diagnose circuits, learn about existing electronic designs and even test a battery.
Why are multimeters not accurate? ›If your multimeter powers up but you aren't getting accurate measurements you may have faulty test leads. Set your multimeter to read resistance and touch the test probe leads together. It should read zero ohms.