| Products > Test Equipment |
| Big Clive's "Trashy" meter, unboxed ( Duratool D03047 multimeter ) |
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| robert.rozee:
--- Quote from: Fungus on April 25, 2023, 11:58:15 am ---This meter is CAT I 500V rated. I think that's a correct rating --- End quote --- i see that Fungus lives in country "00". it is a wonderful land, where if you just print "Cat I" onto a product, you are absolved from any and all responsibility. if someone burns off their hand, you are not responsible. if an explosion kills two people - the person holding the multimeter and a fireman standing next to him - then no worries, the "Cat I" label is completely and absolutely 100% flame and explosion proof, at least for the person who prints it onto the product. it also protects against legal liability and... most importantly, moral responsibility. i feel that we should all move to country "00". it is a great place from which to offer our opinions. cheers, rob :-) |
| joeqsmith:
Agree, CAT I like most of us work with, the concern I have with the meters is if they survive. I have no problem connecting any meter to the low energy sources I typically encounter. Of course, normally I don't use them outside of their maximum ratings. Still, shit happens and I have damaged my fair share of meters. Which is why I ran these tests to get a feel for how robust the various brands are. These tests have been conducted at low energy levels as I have never been concerned with safety. --- Quote from: Fungus on April 25, 2023, 01:00:11 am --- --- Quote from: joeqsmith on April 24, 2023, 12:02:06 pm ---All of the meters shown held up beyond their maximum ranges. --- End quote --- This could maybe have been part of your robustness testing - how high will it go on the voltage range before it freaks out? --- End quote --- I don't normally connect a meter to a steady state source that is outside of it's rated limit. Even at low currents the meter can be damaged. I suspect there more than one fool watched one of my videos and saw me apply several kV to the same meter they owned and thought, hey, Joe shows my meter passed at 8kV so it should be fine to measure my 2kV MOT. :-DD I've received dumb comments accusing me of connecting them directly to a capacitor bank or a DC source. The worse are when they equate what I show to some sort of safety test. The most recent was a youtuber who claimed to work in education where they are involved with a EE program. It's rare I will take the time to hunt someone down but in this case I made an exception. Sure enough, they did not embellish their statements. As fast as they pulled their comments after posting a link on this site, I assume they are a member. :-DD As far as the testing, I have seen what I was looking for. Even with these low energy transients, chemical exposures and mechanical wear test, there is certainly a difference between brands. |
| switchabl:
The "CAT I" marking is IMHO somewhat confusing and doesn't necessarily mean much in terms of overvoltage/transient protection. The long story: there is the concept of "overvoltage categories" (defined for example in IEC 60664-1) which are essentially a classification that helps you to figure out necessary clearances, creepages etc. depending on overvoltages/transients that would be expected to occur in a circuit. Those are related to, but not the same as, "measurement categories" which are supposed to tell the user of a measurement instrument whether it is safe to use it on a particular mains-connected circuit ("CAT ratings"). In particular, "overvoltage category I" is actually defined in terms of concrete impulse withstand voltages (e.g. 1.5 kV for a 300V supply mentioned above) while CAT I is not. IEC 61010-1 used to give concrete values for CAT II and higher and acknowledged that CAT I (not directly mains-connected) could cover a lot of different scenarios and the need for overvoltage protection would need to be determined (and documented) depending on the application. Nowadays, the definition of the measurement categories has been moved to IEC 61010-2-030 and -033 and there is now only CAT II, III and IV as well as "equipment without a rated measurement category" (used to be CAT I). I suspect that the designation CAT I was removed because it was found to be confusing/inconsistent. |
| IanB:
I'm curious--how many people here have actually plugged something into the mains that did not survive and which exploded as a result? My impression is that although the bang and the flash can be quite exciting, the main danger is likely to be flying shrapnel hitting your eyes, and therefore the most useful item of PPE would be safety glasses. I don't recall much mention of that in this thread, but if we were to offer useful safety advice to readers then I think the use of eye protection would be at the top of the list. |
| joeqsmith:
--- Quote from: IanB on April 25, 2023, 05:02:02 pm ---I'm curious--how many people here have actually plugged something into the mains that did not survive and which exploded as a result? --- End quote --- :-DD :-DD :-DD :-DD Are you actually expecting the spirit of Billy Bob Ray to channel through one of the members here? |
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