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| Multimeter CAT II Rating Discontinuation |
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| Fungus:
--- Quote from: bdunham7 on July 25, 2023, 08:36:39 pm ---I'm not saying it is incorrect, I'm saying it is confusing--at least to me. It's a CAT I/1000V rated meter that can't measure 1000VAC. --- End quote --- What's confusing about it? Not displaying a reading with 1000V input isn't the same as being safe when 1000V is applied. |
| Someone:
--- Quote from: bdunham7 on July 25, 2023, 03:03:59 pm --- --- Quote from: Someone on July 25, 2023, 05:25:15 am ---Well done referring to a vague "reference" (you could have quoted but didn't). I've quoted AS61010 word for word https://www.eevblog.com/forum/testgear/is-cat-ii-a-useful-rating/msg4833239/#msg4833239 --- End quote --- My 'vague reference' was your link. I'm not trying to win a debate here--your interpretation makes sense even if it is a bit arbitrary and I would be happy have such a clear and understandable rule. Estimating the distance to my service panel is tedious. I just didn't see any clear evidence presented. If you tell me that these exact words appear verbatim in the standard itself and there is no language that is contradictory or gives further details that would make it less clear, I'll take your word for it. --- Quote from: Someone on April 26, 2023, 11:03:53 am ---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" --- End quote --- The only question I'd have is when you are determining category based on which side of the socket you are on, does that apply to all sockets or just certain smaller ones? --- End quote --- That standard does not discriminate between different plug in equipment, or the outlets they are plugged in to. We have some posters saying they would happily use Cat II out into some parts of their installation, and others saying Cat III is necessary on some of their outlets. Both can be true and appropriate as the standard is only a guidance not some magical 100% true rule of nature that is always correct in every situation ever. The standard just provides for some rules of thumb, that I can point back to as accepted practice if something goes wrong. What's the problem here is a small number of posters trying to argue they can redefine what the standard is to suit their (unknown) motivations, or spread incorrect interpretations of those standards. Yet as I'm typing this there is a user who does not have access to the standards in question is claiming to know what they say, despite being told personally, directly, in public, in this same thread, that what they are saying is incorrect. This forum is turning into a pile of incorrect information from ignorant but noisy posters, drowning out the actually correct and verifiable truth, a general problem with unmoderated internet content. |
| Someone:
--- Quote from: bdunham7 on July 25, 2023, 06:00:40 pm --- --- Quote from: J-R on July 25, 2023, 05:29:31 pm ---Quick reminder, the CAT II labeling removal only applies to handheld DMMs, according to what I posted previously. I have not seen anything yet that states the rating itself is going away or changing otherwise. --- End quote --- Do you know if that is what happened to CAT I or did that go away entirely? --- End quote --- CAT I still exists within the 61010 standards but is not printed next to the terminals of handheld multimeters (and now CAT II specifications aren't allowed to be printed there either). /thread |
| bdunham7:
--- Quote from: Someone on July 25, 2023, 11:05:52 pm ---The standard just provides for some rules of thumb, that I can point back to as accepted practice if something goes wrong. What's the problem here is a small number of posters trying to argue they can redefine what the standard is to suit their (unknown) motivations, or spread incorrect interpretations of those standards. --- End quote --- I don't have any motivations whatsoever other than to try an understand and clarify. If the 'standard' here is just 'guidance' that provides rules of thumb and expects you to fill in the rest with common sense, than IMO that's not much of a standard. I don't have this standard, but other standards that I do know about or are publicly available aren't generally vague and don't require a lot of hand-waving, although you do have to read them carefully and know what all the references and exceptions are. It might explain why they wouldn't want to publish it. :) It the standards are vague enough to allow some manager somewhere to claim that the CAT II bench meter is good enough for the scenario I laid out, then they aren't helping much. But I'm a bit doubtful that they would be that flawed or that Fluke would deliberately (or even negligently) publish false information that clearly contradicts what you are claiming is the standard. My best guess, based only on speculation and language from Fluke's reference, is that there is additional language specifying a single-phase receptacle/plug, not just any receptacle/plug. |
| alm:
--- Quote from: bdunham7 on July 25, 2023, 08:36:39 pm ---I'm not saying it is incorrect, I'm saying it is confusing--at least to me. It's a CAT I/1000V rated meter that can't measure 1000VAC. --- End quote --- Overvoltage ratings are about safety, not the ability to measure. Maybe some internal amplifier would clip, the accuracy would be severely degraded due to V^2/R heating in the divider, or maybe it would even be damaged if exposed repeatedly to 1000 Vrms but not harm the user. Again, IEC 61010 does not care if the equipment keeps working or dies as soon as you turn it on. It's a safety standard, not a quality standard. --- Quote from: bdunham7 on July 25, 2023, 08:36:39 pm ---[I don't think that's a correct or complete statement of the requirements. For example, I don't believe the test procedures specify that the voltage + surge test is done on all ranges. I'm fairly confident Fluke has done their best to apply the standard correctly, but since I don't have it I can't fully understand the details. I'm certainly not claiming the markings are false. I'm not sure at all that the 'any two inputs' requirement applies to bench meters or CAT I/CAT II only devices. And IIRC, Flukes position, or at least their design standard, is not simply that the meter must not explode and injure the user. Here's another model, from the same manfacturer where it seems clearer to me. It also seems evident that the CAT ratings are not meant to apply to the 4W sense jacks. --- End quote --- I think they changed that two decades ago to crack down on the "CAT IV 600V on the voltage inputs but a flimsy glass fuse with CAT I 300V for the current input" nonsense. I don't have access to the full standard so I can't give you the exact quote, but the sense terminals should at least be able to handle the max rated voltage (e.g. 1000V DC or AC peak) on all inputs and range/function settings without any danger to the user. From a 2022 draft of IEC 61010-2-030 from CDV that unfortunately only contains changes to the previous version: --- Quote ---In NORMAL CONDITION and in cases of REASONABLY FORESEEABLE MISUSE , no HAZARD shall arise when the highest RATED voltage or current of a measuring circuit TERMINAL applied to that TERMINAL or to any other compatible TERMINAL, with any combination of function and range settings. --- End quote --- See this archived page from Gossen describing how similar language was in the 2002 version. I can't find any authoritative reference saying the transient tests should also be applied to any inputs, though I've seen discussion on the eevblog forums to that effect. |
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