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 Post subject: Wiggy/Solenoid-type voltage detectors
PostPosted: Tue May 22, 2012 2:54 pm 
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Does anyone know any reference in OSHA documents (formal interpretations, etc.) of Wiggys and similar types of voltage detectors being banned? I have heard this often but cannot find any hits on OSHAs web site that offers any kind of proof. I know that many companies have banned them due to people not honoring the on/off time ratio (1:16 on Wiggys and 1:40 on VoltCons) but do not have any proof to back up the claims that OSHA has banned the testers. Just curious if anyone knows...

Ken


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PostPosted: Tue May 22, 2012 8:59 pm 
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No OSHA "ban" per se. It would be a best practice...falling under the general duty clause just as arc flash does.

They also don't meet "Category" rating requirements (IEC), not valid for "absence of voltage testing", and zap solid state devices when they are removed and the collapsing magnetic field generates a damaging transient spike. Other than those issues, perfectly safe.


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PostPosted: Wed May 30, 2012 8:42 am 
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I would not use them for verification of absence of voltage with respect to a Lockout Tagout operation. May I cite some Electrical Standards, starting NFPA 70E ’12 Article 110.4 (formerly Article 110.9 in ’09) dealing with Test Instruments and Equipment:

110.4 Use of Equipment.

(A) Test Instruments and Equipment.

(1) Testing.Only qualified persons shall perform taskssuch as testing, troubleshooting, and voltage measuring within the limited approach boundary of energized electrical conductors or circuit parts operating at 50 volts or more or where an electrical hazard exists.
(2) Rating.Test instruments, equipment, and their accessoriesshall be rated for circuits and equipment to which they will be connected.
Informational Note: See ANSI/ISA-61010-1 (82.02.01)/
UL 61010-1,Safety Requirements for Electrical Equipmentfor Measurement, Control, and Laboratory Use – Part 1: General Requirements, for rating and design requirements
for voltage measurement and test instruments intended for use on electrical systems 1000 V and below.
(3) Design.Test instruments, equipment, and their accessoriesshall be designed for the environment to which they will be exposed and for the manner in which they will be used.

Typically Test Meters are rated for category of use (voltage ranges ) CAT I-IV at or under 600VAC as follows:
[font=Times New Roman]Digital meters are rated into four categories based on their intended application, as set forth by IEC 61010 -1 [url='http://en.wikipedia.org/wiki/Multimeter#cite_note-23'][24][/url] and echoed by country and regional standards groups such as the[url='http://en.wikipedia.org/wiki/European_Committee_for_Standardization']CEN[/url]EN61010 standard.[url='http://en.wikipedia.org/wiki/Multimeter#cite_note-24'][25][/url][/font]
  • Category I: used where equipment is not directly connected to the mains.
  • Category II: used on single phase mains final sub-circuits.
  • Category III: used on permanently installed loads such as distribution panels, motors, and 3 phase appliance outlets.
  • Category IV: used on locations where fault current levels can be very high, such as supply service entrances, main panels, supply meters and primary over-voltage protection equipment.
Each category also specifies maximum transient voltages for selected measuring ranges in the meter.[url='http://en.wikipedia.org/wiki/Multimeter#cite_note-25'][26][/url][url='http://en.wikipedia.org/wiki/Multimeter#cite_note-26'][27][/url] Category-rated meters also feature protections from over-current faults.[2

From ANSI -61010-1:
Conformity is checked by the following test:



During and after the tests, noHAZARDshall arise.
Multifunction meters and similar equipment are to be tested by changing the Function/Range Selector to all possible settings while connected to the maximum rated source.”
NOTE If test probes are provided with the equipment being tested then they are to be used for the test.
Compliance is checked by testing to verify no hazard occurs when switching selector settings.


Hope this info helps. Also, you should reference a previous Arc Flash Forum Posting on this subject, as follows:

[url='http://www.arcflashforum.com/threads/2203/#post-10496']http://www.arcflashforum.com/threads/2203/#post-10496[/url]


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PostPosted: Sat Jun 02, 2012 3:25 am 
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One note: Get a copy of the actual testing specs for the so-called "Category" rating system. For each "rating" in the system (consisting of a Category and a voltage), the standard specifies a transient overvoltage test that the meter has to pass. The "Category" has nothing to do with usage in an area and the "voltage" is unrelated to the meter's maximum intended use voltage. For instance, the standard does not specify any sort of moisture resistance nor does it specify a maximum use rating. It doesn't even specify physical characteristics of the meter probes. The only thing the standard specifies is a transient overvoltage test.

HOWEVER, everywhere you look, you will see the chart and/or word descriptions of the "intended use" areas and NOT the actual testing requirements. My advise is: ignore everything except the testing requirements. Choose a meter according to the maximum transient overvoltage for your operation. Do not continue to promolgate the "category" as if it has anything to do with intended use. The intended use descriptions apply to RESIDENTIAL electricians only.

IEC gives a table for that. CAT III/1000 V and CAT IV/600 V ratings are IDENTICAL. The meter for those ratings must withstand an 8000 volt transient. Most industrial facilities are just specifying the highest rating (CAT III/1000 V OR CAT IV/600V). Specify both because some meters have one and others have the other. Last I checked, there is no CAT IV/1000 V standard.


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PostPosted: Sat Jun 02, 2012 3:38 am 
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One note: Get a copy of the actual testing specs for the so-called "Category" rating system. For each "rating" in the system (consisting of a Category and a voltage), the standard specifies a transient overvoltage test that the meter has to pass. The "Category" has nothing to do with usage in an area and the "voltage" is unrelated to the meter's maximum intended use voltage. For instance, the standard does not specify any sort of moisture resistance nor does it specify a maximum use rating. It doesn't even specify physical characteristics of the meter probes. The only thing the standard specifies is a transient overvoltage test.

HOWEVER, everywhere you look, you will see the chart and/or word descriptions of the "intended use" areas and NOT the actual testing requirements. My advise is: ignore everything except the testing requirements. Choose a meter according to the maximum transient overvoltage for your operation. Do not continue to promolgate the "category" as if it has anything to do with intended use. The intended use descriptions apply to RESIDENTIAL electricians only.

IEC gives a table for that. CAT III/1000 V and CAT IV/600 V ratings are IDENTICAL. The meter for those ratings must withstand an 8000 volt transient. Most industrial facilities are just specifying the highest rating (CAT III/1000 V OR CAT IV/600V). Specify both because some meters have one and others have the other. Last I checked, there is no CAT IV/1000 V standard.


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PostPosted: Sat Jun 02, 2012 7:16 pm 
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Good info and great responses...Thanks. I do fully understand the category rating system and in fact teach this in my classes. I also instruct students to READ the instructions that come with their meters for intended use as well as all of the other safety requirements listed in the meter's instructions (which normally get thrown away).

The key I think is what Paul stated...use of any electrical test instrument MUST be IAW its designed and intended use but only use a meter with the maximum transient overvoltage available (correct me, Paul, if I have misunderstood your comment).

I have heard so many instructors say that they are OSHA banned, but like I said, I cannot find any such ban in the OSHA electrical standards. The biggest reference is to use electrical equipment in accordance with the manufacturer's or listing and labeling instructions.

As I understand it, the IEC 6-1010-1 is where the table is for the category ratings as well as the specifications for the transient voltage ratings.

Here is the ANSI standard and here is a good article from OSHA referencing the requirements to follow ANSI standard:

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=MOU&p_id=239

ANSI/ISA—61010-1 (82.02.01)

"16.2 Multifunction meters and similar equipment

Multifunction meters and similar equipment shall not cause a HAZARD in any possible combination of rated input voltages, and settings of function and range controls. Possible hazards include electric shock, fire, arcing and explosion.
Conformity is checked by the following test . The maximum rated voltage specified for any function is applied to each pair of TERMINALS in turn, in every combination of function and range controls. The test source connected to the
equipment measuring TERMINALS during this test is limited to 3.6 kVA for measurement category I or measurement category II. For measurement category III or measurement category IV, the test circuit has to be capable of delivering 30 kVA. During and after the tests, no hazard shall arise.

Multifunction meters and similar equipment are to be tested by changing the Function/Range Selector to all possible settings while connected to the maximum rated source.”
NOT E : If test probes are provided with the equipment being tested then they are to be used for the test.
Compliance is checked by testing to verify no hazard occurs when switching selector settings."


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PostPosted: Sun Jun 03, 2012 4:26 am 
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Quote:
The key I think is what Paul stated...use of any electrical test instrument MUST be IAW its designed and intended use but only use a meter with the maximum transient overvoltage available (correct me, Paul, if I have misunderstood your comment).


Not sure where you quoted your text from as this is new to me. For one thing in an industrial environment, a 30 kVA transformer is very small. My guys are routinely working on transformers that are 10 times that and I'd hesitate to say that their meters are under-rated.

Meters that pass IEC 61010 (and all of the derivative standards including UL) are tested with 20 repetitions of a transient at a given voltage and with a given impedance in the source. There is a table of these values located at the bottom of the article on the web site here:
http://www.ni.com/white-paper/5019/en

Note that just a couple years ago, "CAT IV/1000V" did not exist. It does now, rated for a 12 kV transient from a 2 ohm source. Plus, the voltages on that table are supposed to be line-to-ground voltages whereas U.S. practice is to specify line-line voltages as the nominal system voltage if it is unspecified. Also note that CAT IV ratings are identical to CAT III ratings except that every entry is "one up" from the CAT III ratings.

IEEE Std. 516 gives guidance on what size of transient overvoltage to expect for a given system based on the grounding if you don't know for sure. 516 is the basis for the shock protection tables in NFPA 70E, CSA Z462, OSHA (subchapter R and S), and others. But I'd recommend a very specific approach. For one thing, you don't know (if you are troubleshooting) that you don't have a loose ground and thus you may be going into an ungrounded system. Second, much higher transients have been measured in practice in industrial ungrounded systems than specified in IEEE 516 (which is for overhead lines). I'd recommend using a p.u. value of 8 times.

So, for a 480V L-L system (277 V L-G), the maximum transient overvoltage is 3480 V. Typical system impedances for industrial systems are only a couple ohms. So a CAT III meter rated for a 4 kV transient is the minimum, or CAT III/300 V.


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PostPosted: Sun Jun 03, 2012 1:26 pm 
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Hmmm.... confused. What I quoted is from page 112 of this document:
ANSI/ISA—61010-1 (82.02.01)
CSA C22.2 No. 1010.1
ANSI/UL 61010-1
Formerly ANSI/ISA-82.02.01-1999 (IEC 61010-1 Mod)

I had a copy of it on my hard drive...is this outdated or the wrong doc altogether? This same article references the 12 kV transient and 2 ohm source for the cat IV rating but says 10 reps instead of the 20 that you mention.. the quote above is specifically addressing multimeters. This may be an outdated copy. I will check in to it.

Again, great info, Paul - it is much appreciated.


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PostPosted: Sun Jun 03, 2012 7:32 pm 
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Kenneth Sellars wrote:
Hmmm.... confused. What I quoted is from page 112 of this document:
ANSI/ISA—61010-1 (82.02.01)
CSA C22.2 No. 1010.1
ANSI/UL 61010-1
Formerly ANSI/ISA-82.02.01-1999 (IEC 61010-1 Mod)

I had a copy of it on my hard drive...is this outdated or the wrong doc altogether? This same article references the 12 kV transient and 2 ohm source for the cat IV rating but says 10 reps instead of the 20 that you mention.. the quote above is specifically addressing multimeters. This may be an outdated copy. I will check in to it.

Again, great info, Paul - it is much appreciated.


The 20 repetition information I have is from Fluke that quoted this part but not the complete table. I don't have access to the actual standard (and IEC is very pricey with nearly everything they sell). There are two versions of the UL/ANSI version that I'm aware of. There is an even older version of 1010-1 and references to it still exist prior to the IEC document that 70E references. Note also something very screwy about the CAT IV rating. The older version of IEC 61010 defined the usage category but gave no testing data for CAT IV. The testing information came from other parallel documents. In the newer B version CAT IV testing is now supposed to be included.

My interest in the spec is purely in getting to the heart of what it actually means. You'd be amazed at what some standards and specifications out there actually say when you read them. I always pay particular attention to the actual testing requirements because lots of equipment standards turn out to be not what one expects when taking the testing standards into account, and 61010-1 is definitely one of them.


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