Extech DV30 Non-Contact Adjustable AC Voltage Detector

I actually have both this DV30 and the DVA30 which detects both voltage and current. Both these tools are excellent, even indespensible, if you do any electrical work which might include tracing wires through walls. There are very few adjustable sensitivity voltage dectectors in this price range and the adjustment control is needed since these units are very very sensitive (which is what you want!) If all you are doing is checking to see if an exposed wire or terminal is hot, these tools are probably overkill and too sensitive. Better to get one where you are have to touch the wire or terminal like one of the Southwire or other units. Sometimes more is not better. However, if you want to detect or trace hot wires through walls, these units are the way to go and to do better you would have to spend much more (like one of the Amprobe tracers, which I have, which can be very expensive although when you need it, you need it.). These Extech units are good for interior use, detecting through sheetrock walls, etc., but not necessarily best for tracing wires underground (although they would work in some circumstances). In addition, the wires have to be hot (although you could impress, say a 24 ac voltage, for detection purposes if you are comfortable doing that sort of thing. DV30 only detects voltage, which is likely all you need, where the DVA30 can also detect current flow which is useful in special situations since the current detection is even more sensitive (but current has to be flowing which requires a complete circuit, not just have voltage present which just needs a hot wire). I personally like the DV30 since the control dial is easier to use and it has a pilot light to tell you that it is on. I have left on my DVA30 too many times only to find the batteries dead when I go to use it. They need to add a pilot light to the DVA30. In addition, both testers should have an led light at the tip to illuminate your work (although you could tape a small penlight to the sides, not elegant, but ok). Lastly, I'm an EE and have been using various electrical instruments for over 50 years, so I know a good one when I see one.

Products like this act like a Geiger counter. You turn the sensitivity up/down while away from voltage and test against known sources to get into calibration for your present environment. You will also need to recalibrate occassionally as you use it. You can then listen for increased sound around voltage and current runs. You also need to be cognizant of static electricity, don't rub it against wals or otherwise subject you or it to static. I was successful behind 3/4 old style 60 year old concrete style drywall, similar to 2 layers of cement board. I could trace out circuits behind walls well. I just solved a difficult problem thanks to this tool. Again there is some trial and error and recalibrate on. There is no renovation/remodler style product that exists that will achieve tracing wires behind walls without this kind of trade off in calibration and trial and error as you run it across walls. If you are uncomfortable with that process, your only option is to open the wall up or somehow guess at it-- this and any other product like it will not satisfy you. In my opinion the product is in fact better than the cheaper ones-- it is more adjustable, built a bit better, and it has current sensing which does work well and is innovative. In my opinion the product is underrated and deserves more reviews from people that understand it.

As an electrician for over 30 years, good testing tools are a necessity. This tester has the best combination of features I've ever seen and in a compact size that's easy to carry. BUT, the damn thing doesn't last. I've owned 3 of them and they all failed for no apparent reason, just stopped working. This is NOT some cheap knock off, and for this amount of money I damn well expect it to hold up. I have two Fluke meters that have been in service for 15-20 years and they still work flawlessly. Horrible situation! I'm going to replace this with the Fluke T5600.

Adjustable sensitivity lets you distinguish between voltages in multiple wires in a raceway, and the same thing with current. If you question a circuit and can load it up with more current, it is easily detected. If the current is dumped, it will detect it instantly. A really nice time saving tool. I have been using these for around 20 years and would never be without one. If you always turn it off, the batteries last a long time. Love you long time, sucky sucky! Lol

great price, I have 5 of these, however the white sensor breaks off. I have had this happen on 4 of the 5. I just purchased a more known name brand that cost $40 because of this problem.

WOW! For the price, you cannot beat the sensitivity range of this NCAVD. Beware, if you are in RF flooded enviroments, it can easily latch on to those signals. You will have to lower the sensitivity to unlatch from the RFI. But, it can be used as a RF source detector, it works great, I have tried it to locate a bug I made. My wife hid it and I found it with this tool. Plus you can use it to detect voltage on each "hole" on a wall outlet to ensure you don't have a reverse bootleg ground situation.

Es muy bajo el sonido cuando checas continuidad y le falta cuando menos otras funciones

I can't say enough . This is the ONE you buy . I know, I'm a contractor and this works for me every time. I love it. Throw the others in the garbage.

Funziona ma è troppo sensibile se ci sono diversi cavi ravvicinati suona sempre e non si distingue quale sia il neutro.

I have gave it a quick check on my furnace. Since it can detect 12 to 600v, it has no problem to detect furnace control wires, make it easy to pin point the problem.You first dial it all to least sensitive. Then find a 24v live wire as reference, touch with this pen and dial it back about 15 degree until the beep turn fast. Then compare no powered wire get yourself confident on the signals.Good brand and great quality.

Excelente calidad y diseño, superior al Klein Tools que ofrece su modelo similar, también el precio es mejor.El botón de cambio de rango es muy útil para aumentar la sensibilidad en casos de tratar de detectar energía en tubería conduit.