Products > Test Equipment
Big Clive's "Trashy" meter, unboxed ( Duratool D03047 multimeter )
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IanB:

--- Quote from: David Aurora on April 26, 2023, 11:56:43 pm ---
--- Quote from: IanB on April 26, 2023, 04:13:52 pm ---I'm making an analogy. A sensitive mechanical instrument should be treated with mechanical care. Similarly, a sensitive electrical instrument should be treated with electrical care.

--- End quote ---

You're kind of making the same mistaken assumption as the OP here that everything is always controllable- it's not. Devices fail while under test, surges happen, test points can be mislabeled, probing mistakes happen, etc.

--- End quote ---

There's no mistaken assumption here. If you drop your expensive micrometer on the concrete floor and put it out of alignment, that's tough on you, time to buy a new one. Similarly, if you blow up your expensive bench meter by accident, that is similarly tough on you. Time to replace it or get it repaired. What you don't do is get the probes from that expensive meter and recklessly stick them in unknown circuits. If you do that you have only yourself to blame for mishaps.
joeqsmith:

--- Quote from: Someone on April 26, 2023, 09:38:58 pm ---
--- Quote from: joeqsmith on April 26, 2023, 01:07:57 pm ---
--- Quote from: Someone on April 26, 2023, 07:43:45 am ---Every mains socket outlet is CAT III, ...
--- End quote ---
Provide a reference in any of the IEC standards from any country that states that.
--- End quote ---
I quoted the AS61010 standard in the other thread that this has split into. Not having any of the international examples to hand at the moment that will do, and you're free to provide quotes from others.


--- 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"
--- End quote ---
Good luck trying to argue that a mains socket affixed to the wall is something other than the building installation. But we have several people trying to be "clever" and say either side of the socket outlet should be treated the same, when the standard says that is the point of distinction.

--- End quote ---

My home has a tiny little service coming into from a small distribution transformer.  Nothing like what feeds for the buildings where I worked.    Outlets at my house are several feet from the main feed and are behind small CBs which are behind another small one.  Worse thing that will happen if I pull an outlet and short the wires, I blow a CB.  Hardly CAT III or risk of an arc flash.       

Even at work where we have larger services to plug into, it's a long way from the main lines and again fed though various CBs.  Lots to limit the current.  Some of the larger factories I have worked will have their own distribution systems outside in fenced areas.   

I'm not going to get all concerned about my home toaster repairs and my CAT III outlets because it's just not the same thing.  If I have to go into the field, I have equipment for that. 
EEVblog:

--- Quote from: David Aurora on April 26, 2023, 11:49:40 pm ---Exactly, my question was kind of a sidenote (I probably should have just PM'd it in retrospect). I figured the insane cost was probably one of the main stumbling blocks, haha. But yeah- my curiosity was definitely about how the input stages of various models might cope when things go wrong. Which really circles back to the cost thing as well- for the price of some of those things it'd be great to know how well protected (or not) various models are.
--- End quote ---

The robustness of bench meters is effectively stamped on the front. Both of mine (Keithly and Keysight) are CAT II 300V. That screams "I'm delicate please don't hurt me!"
No need for testing, just assume all bench meters are delicate snowflakes.
xrunner:
Some of my bench meters:

GW Instek GDM-8251A

CAT I 1000V
CAT II 600V

Rigol DM3058E

CAT II 600V

Others such as hp 34401a and older bench meters don't specifically state CAT on the front panel (but may in the manual I haven't looked yet).
joeqsmith:

--- Quote from: EEVblog on April 27, 2023, 12:53:36 am ---The robustness of bench meters is effectively stamped on the front. Both of mine (Keithly and Keysight) are CAT II 300V. That screams "I'm delicate please don't hurt me!"
No need for testing, just assume all bench meters are delicate snowflakes.

--- End quote ---

Or test them to a common standard and see how they shake out which is what David is asking about.   No big deal to benchmark them.   
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