Extech DV25 Dual-Range AC Voltage Detector with Flashlight

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.

I have lots of diagnostic tools, but none is as easy to use as this for tracing the actual flow of current in a circuit I can't see. I found the DVA30 easy to use. I used it successfully to trace 120VAC and low voltage AC wiring behind drywall and under cellulose insulation. I could follow 12VAC landscape lighting wiring in yard and under shallow dirt. The separate adjustable sensitivities for BOTH voltage and current detection are very useful to find a signal and narrow down exactly where it is. The strength of beeps and LED flashes varies in proportion to the strength of the signal (not the actual voltage).To get 5 stars I'd like a better quality power switch, more protected sensitivity adjustment wheels and more rugged construction. I haven't had any problems, but those areas could use some improvement. Replacement batteries can be bought inexpensively online and kept in the 'fridge.Really glad I bought it.

I have used low cost voltage detectors for several years to find faults, but was excited to try this more expensive detector out on a dead outlet where my problem likely was going to be in a junction hidden behind drywall. The sensitivity was excellent, but not consistent or repeatable when I did some testing at a breaker panel. I discovered that I was getting readings on all the L1 side breakers of the standard 220 volt split phase panel, but not on the L2 side breakers. Very strange - the tester would read voltage on alternating breakers in the panel and dead on the L2 side ,with no change in the sensitivity adjustment. Checking further down the line of Romex feeds, I got the same type of readings. I double checked L1 and L2 with a good voltmeter, and both legs read exactly the same voltage. All circuits but one were actually good and the problem was down the line from the panel. All circuits tested good at the panel. Since a device that doesn't work all the time is worse than none at all, I decided to return it. Maybe you will have better luck, but I will go back to my tried and true (if not sensitive) voltage detectors.

I use this tester every day...

Voltage is not enough. Need to know if current is flowing. This device is a simple way to determine if current, above 200maAC is flowing. If a circuit has detectable voltage, but it is not drawing current, it has an internal problem, like a heater element in a hot water tank (if switches are closed)Dropped mine. They sent a new one at no costs.