Top pick
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.
After researching the topic, talking to an electrician, 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 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 NCVT3P 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 NCVT3P 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 NCVT3P. 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 NCVT3P’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 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 fall of 6½ feet, so if you get a case of the dropsies, this model has a good 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 of the tool where it looks like it’s under a steadily dripping faucet.
Klein is a reputable company for electrical tools. 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.”