ECN Forum Forums General Topics of the Trade General Discussion Area non-contact voltage testers

I trusted a Greenlee voltage pen once and my dikes have a jagged wire stripper built in now. These voltage testers chirp when you shake them. I don't trust them for nothing.

Let me get this right. Most you people would stick your hand on a 600 volt motor starter or whatever as long as the volt pen said it was de-energized. And your sure it worked because you rubbed it on your shirt?
I hope your insurance is paid up.

I am not sure what causes it but one really wierd thing I have seen more than once is that my non contact voltage testers when used in old houses with knob and tube or old two wire romex sometimes will give me continuous voltage readings off the wooden walls, door jambs or whatever else in the house I touch them near. I figure that this must be inductance or capacitence, from how they used to wire three ways with two wire cables for travellers and the hots and neutrals for same on different circuits. Anybody else ever see this or know why?

The answer to your question for me is yes, without a doubt.

I ask again, what is a non-contact voltage checker for if you can not use it to check for voltage.

I also would like an explanation why some feel a typical digital or analog multimeter is a more reliable method to check for power?

In my mind the most common problem with meters is broken leads. Not a problem with a non contact tester.

Next we have complexity, the more complex an item is the more likely it is to break.

I can see no reason to 'trust' a multimeter more than the non-contact tester for simple "is it on or is it off" type use.

Do you all 'trust' your amprobe?

It is a non-contact device that is very reliable.

Macmikeman,
Very interesting point. Even when fully kiln-dried, timber contains about 6% moisture, not far off ONE AND A HALF PINTS PER CUBIC FOOT in pine! In older houses in summer it might rise to 12%-15%, falling to perhaps 6-10% in the heating months, but in older damper houses it might be as high as 20%, and has to be this high for fungus attacks to proceed. The water is 'locked' into the twisted cellulose fibres of the wood, takes considerable energy to remove, and there is a gradient rising toward the centre. Larger, particularly oak, timbers never dry out fully, and on a big beam, such as in an old church, the core will be as wet as the day the tree was felled, perhaps as high as 50%! So if these pens are very sensitive, they may well detect stray currents in a quite dry-seeming to the touch timber structure with K&T. As an aside, wood also moves dimensionally when moisture content changes, so a woodworker has to allow for it in every object he makes, ( hence panels in doors), an unwanted complication!
Alan

I think the "tic tracer" is a great tool, and use it all the time, but I carry a wiggie with me when I am working, and use it as well.

All testers must be tested on a known live circuit both before and after testing the circuit to be worked on. If you are using the noncontact tester on a bare terminal, it will be ok, but there are cases where they will tell you the conductor/cable is dead when it is infact live. This can occur in tightly twisted conductors, or in cables like NM or SO that have paper inside the outer jacket if the paper is wet. I have even seen this with single conductor USE in wet earth.
PS: I only use my wiggy to test anything that I will be touching with my hands or tools, and I test it before and after on a known live circuit of the same voltage.
Don

I have had my volt tic fail working of roofs of tall buildings. It was a moist day and I was 10 stories up, tested a couple duplexes, got the cutters out and now they are retired. I had this happen a couple times after that, but learned my lesson the first time.

I have never had my noncontact probe (a Fluke, FWIW) show a false negative, but false positive indications are pretty common, especially in proximity to other energized circuitry above 120V to ground.

I have converted a pair of dikes into a wirestripper by relying on (somebody else's) voltmeter, though. Open conductor inside the insulation of one of the test leads....

In addition to the pre-use check on a known energized circuit, a periodic check of the meter's leads using the continuity beeper is recommended.

See this:
https://www.electrical-contractor.net/ubb/Forum1/HTML/000133.html

Note the date of the initial topic.
Has anything changed?

[This message has been edited by Redsy (edited 05-20-2005).]