Multimeter CAT II Rating Discontinuation

[EEVblog]

I got an email from Brymen:

The followings are quoted from safety standard update edition EN61010-2-033:2019 Clause 5.1.5.101. The "CAT II rating" is not allowed anymore for multimeter.
In such kind of condition, the ratings of BM235 will need to change from "CAT II 1000V, CAT III 600V & CAT IV 300V" to only "CAT III 600V & CAT IV 300V". Its  "CAT II 1000V" rating will need to be deleted in the future.

[Fungus]

I totally called it, LOL!

https://www.eevblog.com/forum/testgear/is-cat-ii-a-useful-rating/

[CosteC]

CAT I was removed some time ago too.
On other side, isn't consequence of improved DMM protection, customer ignorance and unfair far east manufacturers?

[Fungus]

CAT I was removed some time ago too.

"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)

[CosteC]

"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)

I agree. I am not IEC however. On other side, today it is much easier/cheaper to make well protected input.

[Someone]

Wow, another round of disinformation.

CAT I was removed some time ago too.

"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

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/

They are safety withstand voltages only, the user should not be injured/shocked if the [prescribed] transient occurs. No guarantee of functionality or correct operation after the transient.

What did change recently is that some standards do not allow a Cat I or Cat II rating to be marked on the instrument, it may still need to pass the requirements for that but it is not shown on the product.

[Fungus]

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/

CAT II makes sense in some contexts but not in a handheld multimeter.

CAT II ratings on handhelds are just a distraction, even an ignorant oaf like me can see that.

[Gyro]

It's going to provide even more incentive for dodgy manufacturers to put CAT III or CAT IV on their meters. Anyone know a good solvent for removing the lettering from mine?

[Someone]

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/

CAT II makes sense in some contexts but not in a handheld multimeter.

CAT II ratings on handhelds are just a distraction, even an ignorant oaf like me can see that.

Says the person who didn't understand the delineation and was adding further confusion to people trying to understand it (and quotes the link to a standard that isnt the key reference for this when relating to hand held multimeters, further exhibiting your lack of understanding/knowledge).

Cat I and II was entirely appropriate for trained personnel, for a consumer device less so.

[Someone]

It's going to provide even more incentive for dodgy manufacturers to put CAT III or CAT IV on their meters. Anyone know a good solvent for removing the lettering from mine?

[sarcasm] MEK [/sarcasm]

[J-R]

Hard to find anything about this as it's all behind paywalls, but I found some previews that seem to clarify a few things:

"This part of IEC 61010 specifies safety requirements for hand-held multimeters for domestic
and professional use, capable of measuring MAINS.

Hand-held multimeters are multi-range multifunction measuring instruments intended to
measure voltage and other electrical quantities such as resistance or current. Their primary
purpose is to measure voltage on a live MAINS. They are suitable to be supported by one hand
during NORMAL USE. "

"HAND-HELD EQUIPMENT such as oscilloscopes, wattmeters, process control multimeters not
RATED for measuring voltage on a live MAINS, clamp multimeters and communications test sets
are not within the scope of this document."


All this is under the heading "5 Marking and documentation" so it doesn't seem to apply to testing or anything else other than labels.


It seems this plan has been in the works for quite some time.  I now see most of the DMMs I've purchased in the last maybe 5-10 years don't have CAT II ratings printed on them.  Also, I recently purchased the Flir DM64 which we know is basically the BM235 but it is limited to 600V instead of 1000V.  (It only has CATIII/IV ratings printed on it.)

So this is probably a two-fold plan to reduce confusion/clutter on the face of the equipment to only two ratings, but also boost safety by requiring CATIII/IV for DMMs that you will be measuring mains voltages while holding it in your hand.


I'm for sure curious about the clamp multimeter exception, as that seems odd.  Maybe it is clarified elsewhere...

[CosteC]

All this is under the heading "5 Marking and documentation" so it doesn't seem to apply to testing or anything else other than labels.


So this is probably a two-fold plan to reduce confusion/clutter on the face of the equipment to only two ratings, but also boost safety by requiring CATIII/IV for DMMs that you will be measuring mains voltages while holding it in your hand.

I'm for sure curious about the clamp multimeter exception, as that seems odd.  Maybe it is clarified elsewhere...

This all is about labels and descriptions on meter and in documentation.
Clamp meters do not measure main VOLTAGE hence are not exposed to overvoltages to the same extend.
If clamp meter measures mains voltage as additional feature, then falls into handheld DMM I guess.

Then CAT I and CAT II are still in use as descriptors for stationary and other non-handheld DMM. Sounds sensible.

[mendip_discovery]

Gradual phasing out of not-as-safe meter designs. Its not a bad thing. Won't matter to the cheap meters we get from places like China as they will just print whatever ratings they want on there.

[Fungus]

Says the person who didn't understand the delineation and was adding further confusion to people trying to understand it

Please tell us all if this outlet is CAT II or cat III:


What class multimeter should I use on it?

[bdunham7]

Please tell us all if this outlet is CAT II or cat III:

What class multimeter should I use on it?

Can you cite a single example of a non-bullshit DMM that has a CAT II/300V rating?  (by "non-bullshit" I mean one where the rating is not just printed on the front as a sad joke)

And a related question (one that supports eliminating CAT II...) can you think of a single example of a circuit that would be CAT II/1000V (Category 2 and in excess of 600V) ?

[Fungus]

Can you cite a single example of a non-bullshit DMM that has a CAT II/300V rating?  (by "non-bullshit" I mean one where the rating is not just printed on the front as a sad joke)

And a related question (one that supports eliminating CAT II...) can you think of a single example of a circuit that would be CAT II/1000V (Category 2 and in excess of 600V) ?

You're asking me?

[bdunham7]

You're asking me?

Sure, but anyone can chime in.

[mendip_discovery]

Says the person who didn't understand the delineation and was adding further confusion to people trying to understand it

Please tell us all if this outlet is CAT II or cat III:


What class multimeter should I use on it?

To me it just looks like a child's first attempt at designing a plug and socket.

[Dr. Frank]

Can you cite a single example of a non-bullshit DMM that has a CAT II/300V rating?  (by "non-bullshit" I mean one where the rating is not just printed on the front as a sad joke)

Well, I just inspected my 34465A from KS, 2015, which is rated on its front panel: CAT II (300V)
Though, it is able and allowed to measure 1000V DC... I have to check, if this is a contradiction.

Anyhow, it is custom in Standardization that a new release of a standard is valid for new products / new development only, but not retroactive.
I.e. these DMMs or other instruments should be still 'legal' and shall not be updated somehow.

Frank

PS: I copy the Regulatory of the 2015 datasheet, which might explain this supposed contradiction of CAT II / 300V vs. 1000V DC.
CAT classification to my understanding now relates strictly to measuring Mains voltages.

[mendip_discovery]

FYI, Fluke's ABCs of multimeter safety
https://res.cloudinary.com/iwh/image/upload/q_auto,g_center/assets/3/7/ABC-meter-safety.PDF

The division of a power distribution system into categories is based on the fact that a dangerous high-energy transient such as a lightning strike will be attenuated or dampened as it travels through the impedance (ac resistance) of the system. A higher CAT number refers to an electrical environment with higher power available and higher energy transients. Thus a multimeter designed to a CAT III standard is resistant to much higher energy transients than one designed to CAT II standards.

The above statement makes me think that this move to remove more CAT2 stuff is because electricians etc are increasingly at risk of being near a higher power than may initially be expected. With more 3-phase stuff going near car chargers being one thing.

[CosteC]

I think it makes more sense in EU than USA and UK.
USA is 120 V, so lower, safer voltages.
UK is primary single phase systems.
EU - in my flat, I have 3 phase (3x230 VAC fixed installation) electric cooker - according to FLUKE it is CAT III, despite IEC61010-1 has other opinion on this topic (FLUKE:  ) however, per IEC61010-1 installation efore my electricity meter/incomer fuses is CAT III - hence even for "home use" I may need to measure CAT III line for checking if my fuses are fine. To do it I would need CAT III 300 V meter - quite rare thing - most meters is better than this.

Per FLUKE lighting in staircase is CAT III - again, IEC 61010-1 would rather categorise it at CAT II - definition of "large building" is vague. Anyway, drawing line between Overvoltage categories is tricky.

One more thing, which may affect FLUKE, an USA company: mostly wooden small buildings in USA/UK provide little EM shielding. Buildings in EU are more often reinforced concrete and this provides some level of shielding, reducing overvoltages from lighting strikes.

Anyway, portable DMM with CAT II only makes indeed little sense, and seems to die out already. For me at least

[bdunham7]

Well, I just inspected my 34465A from KS, 2015, which is rated on its front panel: CAT II (300V)
Though, it is able and allowed to measure 1000V DC... I have to check, if this is a contradiction.

Well, there you go.  Now you can't be sure whether that meter is appropriate to measure the mains in the sockets that Fungus showed! It also shows the awkwardness of putting CAT-ratings on bench meters, especially the ones with 4W resistance sense jacks rated for much less than the CAT rating on the adjacent jacks.  The only bench meter I have that I wouldn't cringe at using on mains doesn't have any CAT rating at all (due to age) and I'd be happy to see the concept of CAT go away on bench instruments. 

[mendip_discovery]

I think it makes more sense in EU than USA and UK.
USA is 120 V, so lower, safer voltages.
UK is primary single phase systems.
EU - in my flat, I have 3 phase (3x230 VAC fixed installation) electric cooker - according to FLUKE it is CAT III, despite IEC61010-1 has other opinion on this topic (FLUKE:  ) however, per IEC61010-1 installation efore my electricity meter/incomer fuses is CAT III - hence even for "home use" I may need to measure CAT III line for checking if my fuses are fine. To do it I would need CAT III 300 V meter - quite rare thing - most meters is better than this.

Per FLUKE lighting in staircase is CAT III - again, IEC 61010-1 would rather categorise it at CAT II - definition of "large building" is vague. Anyway, drawing line between Overvoltage categories is tricky.

One more thing, which may affect FLUKE, an USA company: mostly wooden small buildings in USA/UK provide little EM shielding. Buildings in EU are more often reinforced concrete and this provides some level of shielding, reducing overvoltages from lighting strikes.

Anyway, portable DMM with CAT II only makes indeed little sense, and seems to die out already. For me at least

Erm UK is mostly stone/brick. Don't lump us in with them weirdos across the pond.

The US often has two phases of 120V as they use 240V for some ovens.


In the UK most homes are single-phase, and business uses a lot of three-phase. But I know that many housing projects now are starting to go 3 phase due to the electric car market meaning there is going to be a need for more power.

[bdunham7]

Per FLUKE lighting in staircase is CAT III - again, IEC 61010-1 would rather categorise it at CAT II - definition of "large building" is vague. Anyway, drawing line between Overvoltage categories is tricky.

Fluke is just providing a brief description and some examples, not a detailed standard.  "Commercial lighting" in the US is often 277VAC derived from a 480VAC/3PH service panel, although you can interpret that to include a 120VAC lamp in a hotel room if you like.  Just another reason to eliminate CAT II, I guess.

One more thing, which may affect FLUKE, an USA company: mostly wooden small buildings in USA/UK provide little EM shielding. Buildings in EU are more often reinforced concrete and this provides some level of shielding, reducing overvoltages from lighting strikes.

I think the bigger issue in the US would be the prevalence of local low-voltage power distribution outdoors on poles.  In theory, if lightning hit the pole behind my house, which is the highest nearby object, it could come directly into my house unimpeded other than my poor circuit breakers.

[CosteC]

Per FLUKE lighting in staircase is CAT III - again, IEC 61010-1 would rather categorise it at CAT II - definition of "large building" is vague. Anyway, drawing line between Overvoltage categories is tricky.

Fluke is just providing a brief description and some examples, not a detailed standard.  "Commercial lighting" in the US is often 277VAC derived from a 480VAC/3PH service panel, although you can interpret that to include a 120VAC lamp in a hotel room if you like.  Just another reason to eliminate CAT II, I guess.

Och. USA electric system is really confusing. 120, 240 277 480... I really prefer European 230/400 VAC, even if you add stubborn UK with its 240 VAC which anyway is the same as "continental" 230 V.

One more thing, which may affect FLUKE, an USA company: mostly wooden small buildings in USA/UK provide little EM shielding. Buildings in EU are more often reinforced concrete and this provides some level of shielding, reducing overvoltages from lighting strikes.

I think the bigger issue in the US would be the prevalence of local low-voltage power distribution outdoors on poles.  In theory, if lightning hit the pole behind my house, which is the highest nearby object, it could come directly into my house unimpeded other than my poor circuit breakers.

You mean home panel distributes technically CAT II but as it is long and on poles it is more CAT III if not CAT IV? Anyway creating grey zone, risky installation.
My example in EU is less dangerous and more formal thing. Your example is better. I wonder how some Asia countries or Latin America see it.