The Best Non-Contact Voltage Tester: Certified by 20 Years of Electric - knoweasy

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The Best Non-Contact Voltage Tester: Certified by 20 Years of Electrician Experience

May 08, 2024

The Best Non-Contact Voltage Tester: Certified by 20 Years of Electrician Experience

Using a non-contact voltage tester is the fastest and easiest way to safely check the current in wires, outlets, switches, or old lights that have mysteriously stopped working. It's a useful tool that every electrician carries. After talking to a veteran electrician with 20 years of experience and testing seven leading models for eight months, we found the Klein NCVT-3 to be the best choice.


The Best Non-Contact Voltage Tester


Klein NCVT3P

Klein detects both standard and low voltages and comes with a handy flashlight, which is a great choice for a tool you might need when the lights go out.

The Klein NCVT3P is a dual-voltage model, so it can record both standard voltage (indoor wiring) and low voltage (e.g., irrigation, doorbells, thermostats). And unlike some of the models we tested, it automatically distinguishes between the twoThis feature also makes it compatible with tamper-resistant outlets, which are now required by electrical codes. 

The controls on the NCVT3P are intuitive and displayed. When we tested it in a breaker panel full of fire and dead wires, it was sensitive enough to read dead wires from short distances without giving us false alarms from nearby fire wires. But the most useful feature is its bright LED flashlight, which can be operated independently of the voltage tester. This is a secondary but very useful feature for a tool that's often used in dimly lit basements or situations where the lights don't work, and the Klein was the only model we tested with this feature.

According to the company, the tool can also withstand drops of up to 6.5 feet, which isn't bad considering it's a precision piece of electronics. This model replaces our previous choice, the Klein NCVT-3, which has been discontinued. The two items are identical, except that the NCVT-3P has a slim nose for mounting into a socket.




Milwaukee 2203-20 10-1000V Dual Range Voltage Detector

This dual voltage tester is similar to our selection in the most important ways, but it has a few minor details that are a bit annoying.


If you can't find Klein, we also like the Milwaukee 2203-20 Voltage Detector with LED. It costs roughly the same and is similar to the Klein, which is important because it detects standard and low voltages and is easy to use.

But the flashlight isn't as brightand it can't be used separately from the tester. It also emits an incredibly loud beep and has no mute option.


Who it's for?


Non-contact voltage testers detect power simply by being close to a wire or outlet. They are usually the size and shape of a thick marker, and the detection occurs at the tip of the probe, which in many cases is designed to be pushed into the outlet. Since electric shocks are unpleasant at best and extremely harmful at worst, the tool is useful for even the most minor electrical work, such as troubleshooting a thermostat or installing a dimmer switch.


It's a great tool for DIY electricians, but even people with zero electrical inclination can benefit from owning one. We usually use it as the first stage of troubleshooting before calling a professional electrician.


A non-contact tester can also help map your existing electrical system. I have yet to live in a house that comes anywhere close to labeling its panels correctly, and if you have an older house or condo, then your electrical panels are likely to be mislabeled as well. Fixing this is a time-consuming process, but it is possible. Turn off all the breakers except one, and then check around the house to see what's going on. Once you figure that out, label the breakers and move on to the next one.


How do we pick and test

Most non-contact testers only record standard voltages. After reading up on the subject, we think a dual-range voltage tester is better suited for the home toolbox. It still works the same for standard voltage and has the added benefit of low voltage detection, which is useful for doorbells, thermostats, some AV equipment, irrigation, and some landscape lighting. Dual-voltage and single-voltage models are priced primarily in the $15 to $30 range, so for the non-professional, a dual-voltage model makes sense as a one-stop tool; it's better to have the capability but not use it than to need it but not have it.


List of non-contact tools tested:

  • Klein NCVT-3
  • Milwaukee 2203-20
  • Klein NCVT-1
  • Klein NCVT-2
  • Sperry VD6505
  • Greenlee GT-16
  • Greenlee TR- 12A

When deciding which models to test, we researched products from Amazon, Home Depot, and Lowes. We also focused on reputable power tool manufacturers. From there, we narrowed the list down to seven.


We ran a few tests to determine the overall utility and sensitivity of each tester. First, I turned off one of the circuit breakers in the distribution box and tried to find out which of the 35 wires leading out of it was disconnected. After that, I took an uncharged wire to see how close I could get the tool to a charged wire and still have the tester read negative. In addition to these structured tests, I used the tester to connect some outlets and install some dimmer switches, stoves, ceiling fans, and some chandeliers


Comparison Process


The Klein NCVT-4IR is similar to the one we chose but also includes an infrared thermometer function. It lacks a flashlight and dual range, so we prefer the NCVT3P as a dedicated power tool.

We tested the Klein NCVT-2, which is very similar to the NCVT3P. It's also a dual-range model that auto-detects both ranges, but doesn't have an LED; the on/off button is located on top of the housing (so it's likely to open in your pocket); and the housing doesn't have as durable a feel.

We also looked at the Greenlee GT-16 and the Sperry VD6505, which use knobs to select the sensitivity between low and standard voltage. During our testing, we found that these models picked up signals from other wires when there were multiple wires in the area, making it difficult to know when we had turned the sensitivity down enough to detect only the wires we wanted. It was hard to get the hang of the sensitivity knob and preferred the simpler interfaces of Milwaukee and Kleins.

The Greenlee TR-12A has a two-pin design designed for use with tamper-resistant outlets, but it only reads standard voltage rather than low voltage, so we found the NCVT-3 more useful.


Our Choice: Klein NCVT3P


After researching the topic, talking to electricians, and spending hours testing seven leading models, we recommend the Klein NCVT3P. The NCVT3P has a very intuitive indicator light, a nice on/off button, and an on-board LED that works like a small flashlight, which is a great feature because the light may not work properly when you check the voltage on the wires. It's also compatible with the tamper-proof sockets now required by code. The NCVT3P has a battery life indicator and a durable body to protect its sensitive electronics from drops of up to 6.5 feet. This is an updated version of our previous choice, the Klein NCVT-3, which has been discontinued.


Best of all, the NCVT3P is very easy to use. It is a dual-range unit, so it can detect both standard voltages (outlets, regular wiring) and low voltages (doorbells, thermostats, irrigation wiring). Most testers only detect standard voltage. Unlike most other dual-range models, it automatically switches between ranges without the need for a cumbersome sensitivity dial. The LED bar graph on the side of the tool indicates the voltage you are dealing with. Low voltage detection illuminates the two orange lights below, and standard voltage illuminates one or more of the three red lights above. Many companies sell separate high-voltage and low-voltage detectors, but it makes sense for the layman to have them in one tool, especially if it's as simple as the Klein.


The ED flashlight is a great addition to the NCVT3P. In my basement, the cord is nailed to the ceiling above the fluorescent lights, so it's hard to use the cord even when the lights are on. Of the two models with onboard flashlights, the NCVT3P is the only one that can be operated independently from the test function, which is nice. When the tester is activated, it emits a series of beeps and flashing lights, which is nice to be able to avoid if you just want to use the flashlight.


Our runner-up choice, the Milwaukee 2203-20 Voltage Tester with LED also has a flashlight feature, but it only comes on when the tester is activated, so you have to listen for the beeps anyway, and there's no way to turn off the flashlight even if you're working in a well-lit room. The NCVT3P LED is also brighter than the Milwaukee.


The NCVT3P also has a very durable feel to it. According to the manufacturer, it can withstand a 6.5-foot drop, so if you develop puffiness, this model has a good chance of survival. Additionally, the buttons are all sealed and the battery compartment cover is gasketed, so the NCVT-3 can withstand a little rain and moisture. Klein has a video of the tool that looks like it's under a constantly dripping faucet.


When we asked electrician Mark Tierney if there were any manufacturers he could recommend to homeowners, he told us "The most reliable is Klein." He also likes models with LEDs and says that homeowners, "they'll get two great features in one tool."


Flawed but not a deal-breaker

The NCVT3P is notable for having controls on the side. Tierney warns that models with side buttons are easy to open when placed in a pocket; this is annoying and accelerates battery drain. One redeeming difference with the NCVT3P is that the buttons are flush with the surface; most buttons like these protrude from the side of the tool and can easily be accidentally activated. I left the NCVT3P in my pocket for a day and it didn't turn on once.


Runner-up: Milwaukee 2203-20 Voltage Detector with LEDs


If Klein is not available, we recommend the Milwaukee 2203-20 Voltage Detector with LED. It has many of the same features as the Klein NCVT3P, but the flashlight isn't as bright and can't be used independently of the tester. It also emits an incredibly loud beep (no mute option). This can be useful on a noisy job site, but after I spent 45 minutes checking the wires in my basement, the volume was enough to drive me a little crazy.

Still, the Milwaukee detects both low and standard voltages, and there's no manual switching between them, so it's just as easy to use as the NCVT3P.


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Author: Leb
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