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?