Multimeter CAT II Rating Discontinuation

[Fungus]

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

Yes, but you're from the UK.

To an American it'll look like something they use at NASA.

[themadhippy]

even if you add stubborn UK with its 240 VAC

Nope, uk's  declared voltage is 230V and has been for 20 years

[Neilm]

If I remember what one of the commitee members told me, I think there is another version of -2-033 due for release this year. I don't remember if it a major change or not

In regards the sockets, it is rated CATII probing in the socket and CATIII if you pull it off the wall and probe the back.

[Gyro]

even if you add stubborn UK with its 240 VAC

Nope, uk's  declared voltage is 230V and has been for 20 years

Well, to be more honest, we switched to 230V -6% / +10% as part of European harmonization, ie. we didn't change a damn thing.  Coincidentally, our DNO switched our local substation tap to 230V just the other week - about time because we were getting 250V+ before!


P.S. It was nearer 30 years.

[J-R]

US residential terminology is perhaps open for debate, but generally it should be called split phase, not single phase nor two phase.  The highest potential from ground is only 120V, so that is why the US outlet design works well enough as-is.  You can also get away with touching 120V under most circumstances.  Although electrical code at the moment requires arc fault protection, ground fault protection and outlet shutters.  The precise combination of those depends on the location.  Many homes are grandfathered in but if you perform repairs you must meet the new code.


My gripe with the IEC language on the clamp multimeters is that they actually use the word "multimeter" which invites confusion.  Hopefully they mean clamp "meters" are exempt but clamp "multimeters" are not if they can measure mains voltages.  It's so rare to see a clamp "multimeter" that doesn't measure mains voltages.

The power meter statement is even worse as you will be measuring voltage along with current to get the power.  So no idea why they would exempt those.

Maybe this new revision coming out will clean things up.

[coppice]

Well, to be more honest, we switched to 230V -6% / +10% as part of European harmonization, ie. we didn't change a damn thing.  Coincidentally, our DNO switched our local substation tap to 230V just the other week - about time because we were getting 250V+ before!

We still get a minimum of 250V in our house. Is there any stated time scale for the UK actually adjusting everyone's voltage? Is 230V a even a goal any more, now the UK has left the EU?

[mendip_discovery]

I thought the idea of changing the voltage was to make the sharing of electrical pixies between countries easier.

Anyway you can touch 120V and I can confirm it hurts just as much as 230V.

[coppice]

I thought the idea of changing the voltage was to make the sharing of electrical pixies between countries easier.

That was the goal, but goals change. The main reason we didn't have harmonised voltages in the first place was the urge for countries to be different enough to support local vendors. That wasn't very successful in the long tern, so most product approvals are now to meet global requirements. That could change again, especially if the world seriously backs away from globalisation. If the UK actually stops operating at 240V, will the international product approvals requirements drop from up to 264V to up to 253V?

[Nusa]

Well, to be more honest, we switched to 230V -6% / +10% as part of European harmonization, ie. we didn't change a damn thing.  Coincidentally, our DNO switched our local substation tap to 230V just the other week - about time because we were getting 250V+ before!

We still get a minimum of 250V in our house. Is there any stated time scale for the UK actually adjusting everyone's voltage? Is 230V a even a goal any more, now the UK has left the EU?

230V -6% / +10% never meant changing to 230V. It just meant any voltage between 216.2V and 253V is within spec. The prior UK spec was 240V +/- 6%, or 225.6V to 254.4V, which meant nearly everything was already in compliance from the get-go. Ditto for rest of the EU, at their prior nominal voltages.

Electrical infrastructure lasts a long time, so unless you're building significant areas of the grid from scratch, don't expect change to be quick.

Of course from the international trade point of view it means that appliances must be designed to operate across the entire mains voltage range in the EU market. Avoiding even the perception of incompatibility was much of the point of the "harmonized" rule.

[Gyro]

Well, to be more honest, we switched to 230V -6% / +10% as part of European harmonization, ie. we didn't change a damn thing.  Coincidentally, our DNO switched our local substation tap to 230V just the other week - about time because we were getting 250V+ before!

We still get a minimum of 250V in our house. Is there any stated time scale for the UK actually adjusting everyone's voltage? Is 230V a even a goal any more, now the UK has left the EU?

There never was a goal as such to standardize the voltages even if we'd stayed in the EU. The whole European harmonization exercise was just a political / committee exercise. The native 230V countries had a symetrical tolerance, the 240V country (UK) had asymetrical tolerance upwards and the 220V countries, asymetrical downwards. Nobody had any intention of changing anything. Most switching stuff is 90-264V anyway, it still fits in a 400V reservoir cap.

The only inconvenience was linear stuff. At 250V, the torroidal transformer in my bench PSU would occasionally hum alarmingly and I had to to knock up an autotransformer to drop the supply to my valve amp (transformer primary wound for 230V - the supplier believed the harmonization hype ). I can't see anything to be gained from dropping the design limits to 254V.

[J-R]

Anyway you can touch 120V and I can confirm it hurts just as much as 230V.

The fact remains that a higher voltage translates to higher current flow through the body, which is more dangerous.

To date I've personally never heard of anyone being electrocuted at their house, but I know a handful that have been electrocuted by trees near overhead power lines.  There was actually one just up the road from my house a few months ago.  In that specific case, the homeowner wasn't actually cutting the tree down, it fell on the line during a storm.  The homeowner walked near the tree to investigate and was electrocuted.

[Someone]

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:

Really? you want to continue this again and again and again?
https://www.eevblog.com/forum/testgear/trashy-meters-redux/msg4832993/#msg4832993
https://www.eevblog.com/forum/testgear/is-cat-ii-a-useful-rating/msg4833239/#msg4833239
Keep pretending like you are clever and I'll point out that you're just being a troll. The first one of those links is referenced and freely available, but you look the other way and continue to add confusion and misinformation on the matter.

The standards are extremely clear on where the different Measurement Categories apply, every single socket outlet is CAT III, things that plug into it are CAT II.

[bdunham7]

The standards are extremely clear on where the different Measurement Categories apply, every single socket outlet is CAT III, things that plug into it are CAT II.

Your own linked reference doesn't say that.

Category:  2/ Energy level: Low/ Fault current: <5kA/ Applications:  Home and office power outlets and lighting circuits

You might claim that 'outlets' excludes the wiring to them, but I don't see that 'clearly' anywhere and I've seen other reputable sources claim otherwise.  Also, at least here in the US, home 'lighting' circuits are indistinguishable from 'outlet' circuits.  On fused outlets you can obviously see that the risks change between one side of the socket and the other, but for unfused outlets such as are universal here, there isn't any real difference from the front to the back of an outlet.

[coppice]

230V -6% / +10% never meant changing to 230V. It just meant any voltage between 216.2V and 253V is within spec. The prior UK spec was 240V +/- 6%, or 225.6V to 254.4V, which meant nearly everything was already in compliance from the get-go. Ditto for rest of the EU, at their prior nominal voltages.

In North London, where I grew up, our mains was generally about 260V at night, and 250V during the day. If you go much beyond that a lot of equipment has MOVs that get quite warm. Its important to know the real world limit for protection design.

[Fungus]

The standards are extremely clear on where the different Measurement Categories apply, every single socket outlet is CAT III

WRONG.

From the post on the previous page of this thread:


That reference has been posted here a million times. You'd think people would have read it by now. 

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

Really? you want to continue this again and again and again?

Keep pretending like you are clever and I'll point out that you're just being a troll.

The standards are extremely clear on where the different Measurement Categories apply, every single socket outlet is CAT III, things that plug into it are CAT II.

 

[Fungus]

Getting back on topic, the confusion above clearly shows that every outlet should be approached as if it were CAT III.

(hence all the rules of thumb being posted here)

It's also not impossible that a plugged-in device very close to a distribution panel is CAT III, depending on the power cable, etc.

That's why I say CAT II multimeters are pointless.

[Someone]

The standards are extremely clear on where the different Measurement Categories apply, every single socket outlet is CAT III, things that plug into it are CAT II.

Your own linked reference doesn't say that.

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

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/

[Someone]

The standards are extremely clear on where the different Measurement Categories apply, every single socket outlet is CAT III

WRONG.
[screen shot of not a standard]

Well done, standards don't say what I can see they say because some other (non-standard document) says otherwise?

[Kleinstein]

Getting back on topic, the confusion above clearly shows that every outlet should be approached as if it were CAT III.

(hence all the rules of thumb being posted here)

It's also not impossible that a plugged-in device very close to a distribution panel is CAT III, depending on the power cable, etc.

That's why I say CAT II multimeters are pointless.

I would consider an outlett so close (low impedance - not physical distance) to a major distribution panel more a problem with the installation, not such much a problem with the CAT2  meter category.
Such outlets should have some kind of warning lable and should be used with care.
I have seen the aftermath of a short (flash over in a failing light bulb) on such an installation ( some 2 m from a small breaker box and maybe 3-4 m from the distribution transformer). The 10 kA rated breaker  and GFI failed (closed), a 35 A and 100 A fuse blew and the 3x1.5 mm² cable to the outlett turned from gray to brown.

I see the higher CAT II ratings a bit pointless for a different reason:
Single phase mains is usually 110 V to 240 V nominal. Anything higher voltage (e.g. 480 V 3 phase outletts) tend to be no longer CAT II anyway.

[Fungus]

This is going around in circles as usual.

Let's turn it around: Is there anybody here that thinks a CAT II multimeter makes any sense?

If not? Thread is finished.

[Someone]

Let's turn it around: Is there anybody here that thinks a CAT II multimeter makes any sense?

Yes, plenty of uses for a Cat II multimeter such as production line testing of mains powered plug in equipment. Oh look bench top multimeters are Cat II rated.

[Fungus]

Let's turn it around: Is there anybody here that thinks a CAT II multimeter makes any sense?

Yes, plenty of uses for a Cat II multimeter such as production line testing of mains powered plug in equipment.

So... what meters do they use for that in practice? Brand+model, please.

(or is that just an imaginary use?)

[Someone]

Let's turn it around: Is there anybody here that thinks a CAT II multimeter makes any sense?

Yes, plenty of uses for a Cat II multimeter such as production line testing of mains powered plug in equipment.

So... what meters do they use for that in practice? Brand+model, please.

(or is that just an imaginary use?)

Its not imaginary, around the facilities I work in daily are multiple brands of bench multimeter that are used for automated testing. Sometimes that is on things that are mains powered but not Cat I isolated/protected, but they are never measuring the building infrastructure.

CAT II by definition, CAT II by rating, the right tool for the job.

But you seem to have a goldfish memory span as all this has been put in front of you before:
https://www.eevblog.com/forum/testgear/trashy-meters-redux/msg4833242/#msg4833242

[tomud]

That's why I say CAT II multimeters are pointless.

Seriously ? So you're saying I should throw the Keysight 34465A (CAT II 300V) and Siglent SDM3065X (CAT I 1000V, CAT II 600V) multimeters in the trash? 
If someone wants to throw such CAT II multimeter into the trash, please provide the location of the trash.

[bdunham7]

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

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.

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"

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?  Suppose I have a commercial building with an 800A 480V 3PH panel on an inside wall, with a 2MVA transformer (on a 33kV distribution line) right outside the wall.  Since this is well into the arc-flash PPE-required domain, this panel is in a separate small electrical room.  There is a short length circuit--say 4 feet--of heavy gauge wire going to the next room over where it ends in a pair of L16-30 sockets.  This might be a 100A circuit with 2AWG wire.  I have a very large SMPS that plugs into this socket and I want to monitor the input voltage across one phase and record it.  To do this I want to use my Fluke 8846A, which is rated "CAT II/600V" and I want to record the data using the LAN connector and an ethernet cable attached to my laptop (all aluminum case, of course).  Is that all OK?  If so, then I'd have to agree with others that CAT II is bullshit since I think this would still be in arc-flash territory, requiring CAT IV/600V and at least some PPE.  If it is not OK, I'd have you show me what 'clear' language in the standard says it is not, since I just don't see it in the quote you provided.

As far as CAT I/II being deprecated, it certainly appears that they are for multimeters if the standard now says that the marking shall not be applied.  The usefulness of having a CAT II rating is a bit of a different discussion when you start to throw in bench meters.  For general-purpose handheld meters I don't see the usefulness of allowing CAT II when CAT III is so easily achieved.  I also don't like and don't see the point of CAT II ratings over 300V--you see meters that are CAT II/1000V CATIII/600V CATIV/300V.  You might theoretically run into a CAT IV/300V situation--outdoor/underground subpanel feeds, 208V 3PH service panels, etc.  I don't see how you would ever run into a CAT II/600V (unless you count my scenario above which would be madness) or CAT II/1000V installation.  More than 600V mains and plug-connected with low fault current?