ECN Forum
Posted By: trode non-contact voltage testers - 05/18/05 10:28 PM
Would anybody trust a non-contact voltage tester? (such at the Fluke 1AC-A1, the pen shaped testers that glow in the presence of voltage and fit in your pocket) Would you trust it enough to touch a bare wire or terminal strip that nomally has 600 vac. on it if the "volt pen" showed no presence of voltage? This has became a recommended practice here at the mill. I think you need a contact type tester in this situation.
Comments? Thanks
Posted By: Alan Belson Re: non-contact voltage testers - 05/18/05 10:40 PM
I wouldn't touch a 600v conductor if every piece of equipment in town said it was dead unless I had the fuses in my pocket or the key to a locked-off disco. Get the mug with the non-contact doo-hickey to do it!
Posted By: plcnewbie Re: non-contact voltage testers - 05/18/05 10:54 PM
I agree with Alan I would have to have my lock on and test the circuit myself with a meter that was tested on a known hot circuit to verify that it works.
Posted By: iwire Re: non-contact voltage testers - 05/18/05 11:07 PM
What is it's purpose if not to check for voltage?

I always check that it is working either with a known live circuit or simply rubbing it on my sleeve. It will light if it's operational. I have never had it read dead on a live circuit, it will sometimes give a false live reading.

I carry the Fluke non contact tester and a Fluke T5-1000 Multimeter. I am not sure which is more reliable, they both rely on electronics to produce a correct reading.

Bob
Posted By: Tom Re: non-contact voltage testers - 05/18/05 11:20 PM
I've never known the Fluke Volt Alert to give a false "dead" reading. I test mine the same way that Bob does.

BTW, if you want to be thourough, you should also test your meter on a known live circuit after you use it to check for voltage on a circuit you want to work on. You never know exactly when your meter will quit working.

Tom
Posted By: chipmunk Re: non-contact voltage testers - 05/18/05 11:23 PM
I agree with iwire, test by either using a known AC voltage source, or by rubbing on your sleeve or other part of your clothing, before AND after checking the terminal in question. If there is any chance it may be falsely registering no voltage, for example due to a preponderance of grounded metalwork, I would revert to a contact voltmeter of some kind. But generally, I have found the non contact kind very reliable if treated well. I was always taught that the 'prove your tester actually works both before and after testing an unknown conductor/terminal' routine, and it makes sense to do so with both non contact and traditional testers.
Posted By: Electric Eagle Re: non-contact voltage testers - 05/19/05 02:49 AM
I've found them much more likely to give false positives than a false "dead" reading. They have their place, but they aren't a substitute for a good meter or volt con.
Posted By: u2slow Re: non-contact voltage testers - 05/19/05 03:16 AM
I have the Fluke pen-shaped tester. Its a standard-issue item in our company.

347V or 600V lights the thing up from several inches away... and gives a false positive when you have other live conductors in the same conduit.
Posted By: gfretwell Re: non-contact voltage testers - 05/19/05 03:44 AM
After I have used my tester, removed the fuses or whatever else I need to do to be sure it is dead, I am still grounding that wire before I touch it. Wear your safety glasses ;-)
Posted By: IanR Re: non-contact voltage testers - 05/19/05 11:23 AM
"I am still grounding that wire before I touch it. Wear your safety glasses "

Yeah, wear your safety glasses. While it's a definately reliable way to make sure it's dead, what a fireworks show, guess it's still better than being dead though. Be careful!
Posted By: JFLS41 Re: non-contact voltage testers - 05/19/05 11:48 AM
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.
Posted By: trode Re: non-contact voltage testers - 05/19/05 02:49 PM
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.
Posted By: macmikeman Re: non-contact voltage testers - 05/19/05 06:25 PM
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?
Posted By: iwire Re: non-contact voltage testers - 05/19/05 08:33 PM
Quote
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?

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. [Linked Image]
Posted By: Alan Belson Re: non-contact voltage testers - 05/19/05 09:11 PM
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
Posted By: richard Re: non-contact voltage testers - 05/19/05 10:14 PM
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.
Posted By: resqcapt19 Re: non-contact voltage testers - 05/19/05 10:34 PM
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
Posted By: chrsb Re: non-contact voltage testers - 05/20/05 05:13 PM
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.
Posted By: NJwirenut Re: non-contact voltage testers - 05/20/05 08:24 PM
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.
Posted By: Redsy Re: non-contact voltage testers - 05/20/05 09:18 PM
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).]
Posted By: iwire Re: non-contact voltage testers - 05/21/05 12:11 PM
Great link Redsy, it was interesting.

I think Bjarney's post in that thread bares repeating.

Quote
Use *any* voltage tester with an clear understanding of the device's limitations, and when it is likely to give false readings (or no reading). Experience is a good teacher. The concept is valid and used just about everywhere—a lot of utilities use devices like Modiewark testers at 230kV+. There are no absolutes in this world. We take risks every day, but mostly they are ‘informed’ risks—there may be consequences. The non-contact tester increases job safety, but know when to question its readings—where another type of tester may do a better job.

While I do use my non-contact tester to verify things are dead I am also aware of it's limitations.

Bob
Posted By: Larry Fine Re: non-contact voltage testers - 05/22/05 01:18 AM
In my opinion, the main advantage of a non-contact tester is that it doesn't depend on a grounded return conductor. The tester tells us that there is potential compared to earth, which is the body's return.
Posted By: golf junkie Re: non-contact voltage testers - 05/23/05 09:41 PM
I have had problems with non-contact testers in the past. I found that if I clipped it inside the top of my t-shirt during the summer, by noon it would fail to work. Leave it out overnight and the next day it was fine.

My conclusion was that they don't like heat and humidity. Be careful and check yours on a known live circuit.
Posted By: ianh Re: non-contact voltage testers - 05/27/05 11:26 AM
I would never use my non-contact tester to prove a circuit dead. I would not trust my voltmeter or my Martindale neon-voltage indicator either unless I have proven it against a known live circuit or with my tester box first.

I will also prove it again afterwards just to make sure.

Ian
Posted By: chrsb Re: non-contact voltage testers - 05/30/05 12:12 AM
http://www.osha.gov/dts/hib/hib_data/hib19911218.html
Posted By: e57 Re: non-contact voltage testers - 05/30/05 12:38 AM
The other day, I saw that Fluke has a new model that senses proximity, and contact? 40-600VAC it also has an LED flashlight on it. It was also very small, so if you had to get close to a conductor, you would have you knuckles against it too. I saw it on the counter at a supply house, but they don't have it on thier website yet.

I thought to myself about it, if you have a flashlight with a dead battery, don't you also have a non-contact tester with a dead battery.
Posted By: DougW Re: non-contact voltage testers - 05/31/05 05:29 PM
I saw those Flukes up at the supply house the other day.

About $20 or so. Neat idea. It get brighter / changes color the closer you get to a voltage carrying conductor.... looks like with practice you could tell the difference between line and neutral with it.

e57 - think of it this way... if the flashlight is dead, at least you have confirmation that your tester is teats-up... [Linked Image]
Posted By: mullet Re: non-contact voltage testers - 06/01/05 01:01 AM
All test equipment performance relies on the skill of the operator.I have been in the electrical trade for 30 years and the no contact testers are one of the most valuable tools I own. Common sense being most important. The testers can tell you much with proper interpretation. Given there are limitations.
They will show a hot even if the is no neutral. They will sometimes give a false positive due to inductance. They will not read through wet romex. (This condition is fully disclosed as a warning with the tester I currently use). They can fail just as any other battery operated device.
I always test on a known live circuit or rub the tester briskly on my sleeve to see if it is working.
I have used many types of these testers and have settled on the one osha uses. In my opinion it is the best.
There is no switch to malfunction and no external metal parts.The tester I use is a santronics. http://www.santronicsinc.com/
These testers are also very tuff.
I also second the warning posted by chrsb since the voltstick is made of metal.
Posted By: William Runkle Re: non-contact voltage testers - 06/01/05 01:58 AM
What is the beef? If you don't trust the taster don't have one or use one. Just don't go knocking the guys who do Have and use them it is their choice. For the record I have one and use it on a regular basis.
Posted By: mullet Re: non-contact voltage testers - 06/01/05 03:00 AM
Hello William, no beef but, If your reply is directed at me and if you’re talking about the voltstick Just want to say that I personally am not “ knocking it (The voltstick) or the guys that use them
The voltstick may be the best thing since sliced bread, but when I find a legitimate warning, which in my opinion is merited, I feel it would be very complacent of me not to share the warning. Isn’t that one thing this forum is for, to promote safety and improvement? And I also wanted to share the option of trying the santronics tester, which I feel is also a very good tester and a useful tool.
. I have used many other testers but never the voltstick.
The warning posted is not my opinion, but the findings of a government agency that is in place to protect the consumer.
If you are talking about no contact sensors in general. Sorry about the missunderstanding.
Posted By: Trumpy Re: non-contact voltage testers - 06/01/05 04:54 AM
To answer the original question:
Quote
Would anybody trust a non-contact voltage tester? (such at the Fluke 1AC-A1, the pen shaped testers that glow in the presence of voltage and fit in your pocket) Would you trust it enough to touch a bare wire or terminal strip that nomally has 600 vac. on it if the "volt pen" showed no presence of voltage?
In a nutshell, no I wouldn't.
Batteries can go flat at any time.
I'd only touch a wire that was shown to be dead by a non-contact tester, after having re-tested it with a reliable contact type tester.
Non-contact testers use a Hall-effect sensor in the tip to detect the changing magnetic field from the AC voltage in the wire, the batteries are used to drive either an LED indicator or a small piezo unit or in some cases both.
Having had experience with non-contact testers up to 66kV level, the importance of having good, well looked after test gear and the need to constantly check the testers integrity, really sinks in.
To have a tester fail at these kinds of voltages, would be devastating. [Linked Image]
Posted By: The_Judge Re: non-contact voltage testers - 06/01/05 11:20 AM
Quote
JFLS41 wrote:
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.

I agree, I've found the Greenlee testers to lie like crazy. If you don't like the indication it's giving you, shake it for the opposite answer. [Linked Image] I went through three defective ones in the course of about a week, and pitched it in favor of a Fluke pen tester. I've found the Fluke to be very reliable. [Linked Image]
Posted By: derater Re: non-contact voltage testers - 06/02/05 12:37 AM
I like the GB nc tester (it's red)down side is hearing aid type batts.;expensive,not found everywhere;upside is self testing,push the clip and it chirps when batts. are ok,then known live,then suspect wire.
Posted By: gfretwell Re: non-contact voltage testers - 06/02/05 01:01 AM
I too have the Greenlee. It is handy for diagnosing 3 way loops and such but it will never be the end all "this wire is safe to touch" tool for me.
Posted By: William Runkle Re: non-contact voltage testers - 06/02/05 01:09 AM
No mulet it was not at you at all It is from the start of this post which is now getting to for and against and I stated use what you are comfortable with if it is any testing equipment anyone using this forum is more than qualified to use it. Remember this is The Electrical Contractor Network and usually to be an Electrical Contractor takes a four year apprenticeship and hold a Journeyman License two years to become a Master Electrician also included into it testing and a passing grade for both Journeyman and Master. And yes I relize other than just Electrical Contractors are on this forum But I try to post to the Electrical Contractor so again what is the beef? You use it and you like it fine if you ddont't like feel unsafe and don't trust it and wouldn't use it that is fine. Again use what you feel is safe and adequate for you not because someone else would or wouldn't use one. I have a non-contact, a Fluke amprobe an Amprobe amprobe and multimeter and also a Digital multi-meter and somewhere an ols Simpson 260 VOM that I am not even sure that still works and I use them all at different troubleshooting service jobs I get but I always use what I am comfortable with that I know it is safe.
Posted By: William Runkle Re: non-contact voltage testers - 06/02/05 01:15 AM
No mulet it was not at you at all It is from the start of this post which is now getting to for and against and I stated use what you are comfortable with if it is any testing equipment anyone using this forum is more than qualified to use it. Remember this is The Electrical Contractor Network and usually to be an Electrical Contractor takes a four year apprenticeship and hold a Journeyman License two years to become a Master Electrician also included into it testing and a passing grade for both Journeyman and Master. And yes I relize other than just Electrical Contractors are on this forum But I try to post to the Electrical Contractor so again what is the beef? You use it and you like it fine if you ddont't like feel unsafe and don't trust it and wouldn't use it that is fine. Again use what you feel is safe and adequate for you not because someone else would or wouldn't use one. I have a non-contact, a Fluke amprobe an Amprobe amprobe and multimeter and also a Digital multi-meter and somewhere an ols Simpson 260 VOM that I am not even sure that still works and I use them all at different troubleshooting service jobs I get but I always use what I am comfortable with that I know it is safe.
Posted By: livetoride Re: non-contact voltage testers - 06/02/05 04:12 AM
I do service work on every thing from single family to 12kv and use the touch less all the time. I was taught to work everything as if it was hot all the time. I had a GB for years and liked the chirp to test feature, but it gave more false positives than the fluke pen I use now. I just bought a new fluke light/touch less two days ago and the one thing I don't like so far is no audio alarm and the LED is harder to see. If you work safe and know the limitations of the tools you are using all will be well, get careless and you will be toast no matter what tester you use. Rod
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