Greenlee GT-16 Adjustable Non-Contact Voltage Detector, 5V - 1000V AC,Green, Greens

I have used a Greenlee detector of this sort that was not adjustable and some other brands, a $3 cheapie and a screwdriver that alerted when you were working on a hot outlet without disconnecting it, after all, I am a gadget geek :-). They worked simply. You touched (or neared, the probes were insulated) the probe to the wires that you were interested in - if the device alerted, the circuit might not be safe. Every time you used it, the instructions warned you to check it on a known hot circuit to insure that it would alert so that you could be sure that if it did not alert the circuits were not hot. While the instructions told you to do it every time you turned it on, most people would probably do it at the beginning of each job phase if they were paranoid (you know, the sort who lives around wires that might be live) and once every couple days if they were not.But they did not have a high degree of discrimination. Stick the probe into a plug that was attached to a hot socket, and it would alert - on both sides, hot and neutral. It was set to error on the overly sensitive (more alerting) side - so any energy in a wire in the household voltage range kicked it off. One of the devices was worse, it would alert if an adjacent wire in another box was hot even if this circuit was not hot. Sigh, that was a bit too sensitive, but I used that screwdriver to tell me that I had to be extra careful putting this outlet in hot.Now, this device is actually more interesting. For example, you can adjust the sensitivity to alert when it is "plugged" into the hot side of the plug (again, no actual contact is made, the probe is near the hot conductor insulated by plastic), and not when it is "plugged" into a neutral - pretty simple to adjust it that way. When the sensitivity is all the way up, your one year old can plug it into her belly button and when it flashes and beeps she will giggle because somehow she gets that it is a big game that she has "juice" in her belly button (but not in her ear, because you slide the sensitivity down. Then she learns that with the sensitivity all the way up she can play a simple tune (one note rhythm) by grabbing it differently when the sensitivity is set to max. And it can tell you that the wire from your USB charger is hot.There is only one control on the device. At one extreme (rolled toward the heel of the device) it clicks to turn the device off. Rolled toward the nose, it clicks to turn the device on. The device starts at max sensitivity. As you continue to roll the control to the nose, the sensitivity decreases. To set it, you have two possibilities, well, three. Possibility one is that you turn it down about an 1/8th turn from "most sensitive" and it will probably be OK, so long as you check it to see if it alerts at all. Possibility two is that one is for looking at clearly hot wires and wire breaks. Stick the probe into the hot side of an outlet and roll the control forward until the alerting stops, then back towards the heel until the alert starts again. It should alert continuously when in the hot side of an outlet and not alert when the probe is stuck in the neutral side of the outlet. Simple, no? Set this way, you should be able to use it to find broken wires, as per the instructions.As a safety probe, I like it a bit more sensitive. Do the same thing, to start with, but then stick it in the neutral side and continue to roll the control toward the heel until it alerts again. The device should alert when stuck into either side of the outlet, and not alert in the air away from wires. Check it on a live extension cord, it should alert.This takes a few seconds, and it is not quite as convenient as just turning it on. But if you believe the instructions and if you believe that you can't trust the absence of indication as an indication of safety, you are gonna test your probe when you use it no matter whether it is adjustable or not. To adjust it adds 15 seconds to the setup and allows you to set the sensitivity and alerting the way you want it, and that will save you time on the other end of the job.I like these devices. IMHO, no one who is working on household circuitry should not have one.By the way, first time I saw one, the man using it used the probe first and then, if the probe did not react, he checked the circuit again with a multimeter. Why? His logic was that he wanted a fully insulated tool for the first probe in case there was some huge voltage leaking in, and then he wanted to use a different tool that used a different measuring scheme to back that first tool up, because he really did not want to get shocked, burned, or killed.A few months later he was hospitalized. He wired something in a house up hot, not just an outlet, a subpanel on an existing branch circuit that someone did not want to have disconnected. It took a few seconds lapse and he spent quite a while in the hospital and didn't return to work for a year.These safety tools only work if you pay attention to them.

It is very good dependable.

Very easy to use. Can't go wrong.

It does what it says it will do. I like being able to adjust sensitivity. The alarm is nice and loud. Could the on/off/sensitivity switch be better, yes. It's a bit lightweight. Maybe a better design for a separate way to turn off/on and sensitivity that was not combined. Until then, like the broad voltage range and very handy.

I am by no means an electrician and frankly hate working with electricity. However in my office job, I saw a guy doing some work and he had an older version of this tool and I talked to him about it. I thought it was pretty cool (even if I never used it seriously) to be able to track down live wires so I bought one (actually bought 3 - other two as gifts).So figuring I might never use it, this past weekend I noticed my lamppost was not working outside. Also some low voltage lights on the same circuit were out. Because the installation of that line was done in the garage and after the house was built, the lines were in plastic conduit and not in the wall but on the surface. There were two conduits, one going into a ground fault receptacle and one coming out. The problem was, I didn't know what breaker to throw to shut off the power to replace the receptacle and then it occurred to me to try the tool.It worked perfectly as I touched it to the outside of the conduit coming in, it flashed and made noise and when I touched it to the one going out, it did nothing. What amazed me was the two conduits were an inch apart so it was sensitive enough to not pickup "overflow" from one to the other. I was able to throw breakers until the incoming conduit stopped flashing and blinking...worked like a charm exactly as it should have. Love it. May never need it again, but who knows.

I bought this after seeing comparisons to other voltage detectors on You Tube. I like that it has an on/off button (I believe it shuts off automatically after 5 minutes of non-use anyway), that it does self checks for proper operation, that it blinks 1/second so you know it's working and it has a lifetime warranty from a U.S. company. I would buy it again. I read some reviews that the battery cover is difficult to remove. It's not. All you have to do is grab the battery compartment cover near where the on/off switch is and pull it straight back. You don't pinch the sides of the cover. To protect this instrument I made a case from 1 inch (inside diameter) PVC about 6 3/4 inches long. I cemented a PVC slip cap to one end. There is enough room for the two AAA batteries plus the voltage detector. (I remove the batteries from the detector when I'm not using it). Once it's in the case I slip another PVC cap on the other end. Doing this protects it from damage in my tool box. t works well at detecting hot wires as it should. I haven't had occasion to use it in a crowded box.

I have been using this device on and off but last year the screws that were securing the metal washer to the cap broke off!! I was forced to use Electric Tape to secure the cap which was a hassle when replacing the battery.The problem is that the plastic nipples for the screw holes (inside the cap) are fragile. They bascially chipped away (broke off) one after the other! I would suggest better injection molding for this part. And now the actual device does not detect voltage and it just beeps!! The LED light has stopped working and the device simply beeps; but does not detect.I was not planning on buying a new one of these every few years so I suspect I would need to look for a better made device and can't recommend it.