Who makes the best volt-pen, in your opinion ?
The instructions with all of those devices say something like the following:
When using the Tester, if tip does not glow, voltage could still be present. (Fuke)
If no indication, voltage could still be present. (Klein)
Do not assume that no voltage indication means the circuit is de-energized. (Ideal)
That's another good thing about the Amprobe it uses plain old AAA.I like the type that use a more standard battery. I hate having to find a specific battery for those type of devices
Other types of test equipment can be tested using the live-dead-live method. Because of the way that non-contact testers work, you really can't do that with them. If the conditions on the known live source are not EXACTLY the same as the conditions on the circuit being tested, you have not really done a live-dead-live test.The same caution should be used when using any type of test equipment.