Products > Test Equipment
Multimeter CAT II Rating Discontinuation
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Someone:

--- Quote from: bdunham7 on July 27, 2023, 03:15:53 am ---
--- Quote from: Someone on July 26, 2023, 01:28:47 am ---Otherwise you end up with an impossible to meet standard that covers a soaking wet gorilla probing a socket outlet outside in the rain, which is connected back to the poles with some obscure 120mm2 cable, during lighting strike on the nearest pole.... and the meter needs to continue operating perfectly afterwards despite being on current mode and connected across the phases.
--- End quote ---
My contrived example was based on things that I've either seen and handled myself or that I'm actually sure exist and are reasonably common.  I understand the need for some simplicity and that they don't want to require a complete fault current analysis signed off by a PE before anyone can ever connect a meter to anything.  That doesn't mean there isn't room for improvement and if what you insist about the standard is correct, there's some pretty low hanging fruit there IMO.
--- End quote ---
The standard 61010, is only about product safety and communicating its safety limits, not about how/where to use the device. That standard divides the product specifications into Measurement Categories for the purposes of confirming to their different safety tests, nothing more, and describes the typical situations they expect those (broad and simple to define) categories apply to.

In real world that maps to use the majority of the time. But a learned/educated user knows what the different CAT ratings mean in voltages and current, so they can be confident where a CAT II could be safely used on some part of the permanent wiring. But only because they have measured or calculated things like the prospective fault current and know there is a lightning arrestor etc. In the absence of that extra information the simple explanations are a good start but not infallible, local workplace safety laws then come in and say how you should actually choose an appropriate rating (which in Australia lines up directly the 61010 standards delineations).

I think the 61010 standard are a good balance of simple delineations and realistic limits that aren't too hard to achieve. That may not work in other countries with their specific electrical codes.
bdunham7:

--- Quote from: Someone on July 27, 2023, 06:18:52 am ---The standard 61010, is only about product safety and communicating its safety limits, not about how/where to use the device. That standard divides the product specifications into Measurement Categories for the purposes of confirming to their different safety tests, nothing more, and describes the typical situations they expect those (broad and simple to define) categories apply to.

--- End quote ---

That seems reasonable and understandable to me.  But if the language you posted is simply a description of typical examples then it is just dicta (explanation) and not actually part of the standard's requirements per se.  That doesn't seem to mandate a universal bright line rule that the border between CAT II and CAT III is alway exactly at the wall socket body.  If certain jurisdictions adopt a policy that does match that (hopefully adding the 'single phase' part) then that becomes your rule.  That doesn't make it universally clear for everyone and I don't think that policy has been adopted here in the US.
Someone:

--- Quote from: bdunham7 on July 27, 2023, 07:44:05 pm ---
--- Quote from: Someone on July 27, 2023, 06:18:52 am ---The standard 61010, is only about product safety and communicating its safety limits, not about how/where to use the device. That standard divides the product specifications into Measurement Categories for the purposes of confirming to their different safety tests, nothing more, and describes the typical situations they expect those (broad and simple to define) categories apply to.

--- End quote ---
That seems reasonable and understandable to me.  But if the language you posted is simply a description of typical examples then it is just dicta (explanation) and not actually part of the standard's requirements per se.  That doesn't seem to mandate a universal bright line rule that the border between CAT II and CAT III is alway exactly at the wall socket body.  If certain jurisdictions adopt a policy that does match that (hopefully adding the 'single phase' part) then that becomes your rule.  That doesn't make it universally clear for everyone and I don't think that policy has been adopted here in the US.

--- End quote ---
Pretty much, the 61010 standard makes a Measurement Category delineation as an example and not as some golden rule that must be implemented by installations, other equipment, and working practices, the standard is just defining safety compliance tests of measurement equipment. The categories being models that are used to motivate the tests. But if you see a 61010 Measurement Category specified on a meter/product then you know what voltages/current is claims to survive, and it is a quick way to ask as one example "will this meter be safe under a 5kA fault?" which is roughly the worst case we would see on a socket outlet (3 phase 50A outlet at a 1% droop).

The 61010 standard clearly says their definition of Cat II vs Cat III is either side of the socket outlet. Other standards/practices (as in Australia) have adopted that. Noisy posters continuously question that in obnoxious fake concern and without basis.

Measurement Categories are defined by 61010 (and some other standards) no-one gets to redefine them locally/personally and claim the 61010 standard is wrong, that's inventing some other new categories of some other different standard. If you want to talk CAT xx then refer to the standard that's defining it and there is zero room for variation/misunderstanding/confusion (that some posters seem intent on pushing/persisting).
bdunham7:

--- Quote from: Someone on July 27, 2023, 10:58:49 pm ---the standard is just defining safety compliance tests of measurement equipment. The categories being models that are used to motivate the tests. But if you see a 61010 Measurement Category specified on a meter/product then you know what voltages/current is claims to survive....

--- End quote ---

I'm good there--there's a table of voltage and surge test levels for each catetgory.  The CAT rating of a meter is based on or verified by which tests and inspections it can pass.


--- Quote ---The 61010 standard clearly says their definition of Cat II vs Cat III is either side of the socket outlet.

--- End quote ---

That directly contradicts what you just said above.  A CAT II (xxxV) meter is one that passes the stated surge test (and other requirements of course) and CAT III meter is likewise one that passes its respective tests.  The standard mentions that an example of a CAT III environment is the wiring behind a wall socket.  But that in no way 'defines' what a CAT III meter is and you have just said that the CAT ratings are related to the capabilities of the meters and not definitive statements about where the meters are used. 


--- Quote ---Noisy posters continuously question that in obnoxious fake concern and without basis.

--- End quote ---

You can disagree all you want if you think the two lines you've quoted without context (not that I'm expecting you to provide it) are the final authority, but questioning peoples motives and claiming the counterarguments are 'without basis' is a bit much.  The information Fluke publishes on the matter directly contradicts what you are claiming and I'm not willing to write them off as badly misinformed idiots just yet.  That and their interpretation or explanation makes a lot more sense. 
Someone:

--- Quote from: bdunham7 on July 27, 2023, 11:59:17 pm ---
--- Quote from: Someone on July 27, 2023, 10:58:49 pm ---The 61010 standard clearly says their definition of Cat II vs Cat III is either side of the socket outlet.
--- End quote ---
That directly contradicts what you just said above.  A CAT II (xxxV) meter is one that passes the stated surge test (and other requirements of course) and CAT III meter is likewise one that passes its respective tests.  The standard mentions that an example of a CAT III environment is the wiring behind a wall socket.  But that in no way 'defines' what a CAT III meter is and you have just said that the CAT ratings are related to the capabilities of the meters and not definitive statements about where the meters are used. 

--- Quote ---Noisy posters continuously question that in obnoxious fake concern and without basis.
--- End quote ---
You can disagree all you want if you think the two lines you've quoted without context (not that I'm expecting you to provide it) are the final authority, but questioning peoples motives and claiming the counterarguments are 'without basis' is a bit much.  The information Fluke publishes on the matter directly contradicts what you are claiming and I'm not willing to write them off as badly misinformed idiots just yet.  That and their interpretation or explanation makes a lot more sense.

--- End quote ---
Again with your vague/non specific references to "something". Please quote if you think something specific is incorrect.

To make this blindingly obvious I'll keep quoting in context:

--- Quote from: Someone on April 26, 2023, 11:03:53 am ---Fluke isn't following the standard from which those categories are defined (61010) and would be misleading in typical installs in Australia and the UK (and probably other countries that I am less familiar with).

61010 measurement categories are really simple:
"CAT III is for measurements performed in the building installation"
"CAT II is for measurements performed on circuits directly connected to the [mains] voltage installation"

As mentioned in the other thread(s), its very very simple: something that plugs into a socket outlet is immediately CAT II, unless you are on the other side of safety isolation/insulation and then its up to you to know what the range of voltages/currents could be (perhaps use a more modern standard to help) and check that the multimeter/measurement tool has suitable withstand and/or breaking capacity.
--- End quote ---
Those are word for word quotes [editor rewording in bracket] from AS61010-1:2003
which I have a licensed copy of, and its currently in force and up to date:

--- Quote from: Someone on July 24, 2023, 08:01:26 am ---Wow, another round of disinformation.
--- Quote from: Fungus on July 24, 2023, 07:03:37 am ---
--- Quote from: CosteC on July 24, 2023, 06:27:28 am ---CAT I was removed some time ago too.
--- End quote ---
"CAT I" is useful information - it lets you know the meter won't die if you apply the rated voltage with the meter set to Ohms (for example).

(assuming a CAT rating means "meter won't die at this voltage" - something else they ought to clarify in the standard
--- End quote ---
Measurement Categories I and II are not discontinued or removed, AS61010 still lists them as current:
https://infostore.saiglobal.com/en-us/standards/as-61010-1-2003-121163_saig_as_as_254253/
--- End quote ---

So where in that I am contradicting myself? A direct quote of what the standard says, is... what it says. All these "arguments" that it means or says something else are factually incorrect. AS61010 definitions of Measurement Category:

--- Quote from: Someone on July 27, 2023, 10:58:49 pm ---The 61010 standard clearly says their definition of Cat II vs Cat III is either side of the socket outlet.
--- End quote ---
Fluke may well provide different guidance on where they see those measurement categories applying, but that does not change the standard or override it. They have not rewritten or produced some new standard, or said what they write is communicating the 61010 standard (Fluke reference the earlier IEC 1010). Its some marketing material that uses Measurement Categories as you know categories of measurement products and how they think that maps to the (US centric) "real world".

Fluke nowhere claim to be providing a copy or representation of the 61010 standard, yet now you're claiming that too. Where is the basis for that claim? Fluke only talk about IEC 1010, where as Dave in the OP talks about 61010.

Or as a simple example of why the Fluke examples are misleading (in other countries only?) is that Australia requires a maximum droop in the voltage at socket outlets under maximum load. The length of the cabling is pretty much irrelevant to the fault current as we are required to maintain the same (maximum worst case) source impedance at any length. This argument has already been presented, yet here we are again with mutltiple people saying FLUKE IS OUR GOD, TRUST FLUKE there can be no other truths.... while completely misunderstanding and misrepresenting what Fluke are communicating.
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