We use the "touch lite" units for a quick reference....but we check with a "wiggy". I use a "tic-tracer" that "beeps" as a helper to locate cb's if I'm alone. It don't take coffee breaks, sick days, or complain! John
I remember back at the tech I was in the co-op program. On the job one of my 1st days there was this veteran electrician who they called the human wiggy. I asked why, so they introduced me to him and he showed me how he checks for live ckts with his two fingers! I couldn't believe it, so I checked with a voltage tester sure enough it was live. Then he said to me it was initiating time! I was considering running at that instance, but he just laughed and said, gohead it won't hurt u it just runs between your two fingers. Never touched it. That was 20 yrs ago, every once in a while I still run into the ole human wiggy, wondering if he's lost a few brain cells over the years.
Sven: The "touch lite" tester is an item made by Fluke, Amprobe, Gardner-Bender, TIF, etc. It's similar in size to a magic marker, or a "fat" pen. Operation is: You touch the tip on a "live" conductor and the tip illuminates. Some models have a audible tone additionally. The concept is that you can have an indication of potential (voltage) in a conductor without having to open any splices, or "skin" the conductor. The tip of the Fluke model is capable of fitting into the "hot" slot of a receptacle.
They are a great tool for a fast indication of voltage.....BUT they do not "indicate" what the voltage is. Voltage ranges of 24 to 1500/122000 volts are available, DEPENDENT on the unit you buy. The hi-voltage TIF model requires a hot stick adaptor. Price range is $15 to $125.00.
I use a Fluke. I used to use a cheaper one, I beleive it was a GB. The problem with the cheaper ones (and it can be a problem with the better ones too) is that when going inside an enclosure to check for hot wires, a cheaper one will light up as soon as you get close and you cannot determine what is hot and what is not. These testers are not the final say for me either but can be valuable to seperate circuits etc.
I think they are the "cat's meow"! If knowing whether or not a circuit with "hazardous" voltage is present it is great. Obviously it can't let you know exact voltages. I found one that worked 0-24 volts. It was great for tracing fire alarm circuits.