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

--- Quote from: joeqsmith on April 26, 2023, 01:55:56 am ---
--- Quote from: switchabl on April 25, 2023, 10:10:52 pm ---I feel old now.

--- End quote ---

You and me both! 


--- Quote from: switchabl on April 25, 2023, 10:10:52 pm ---What I hope people take away from this:
- CAT II, III, IV have very specific meanings in terms of overvoltage protection

--- End quote ---

As a general observation, meters that have been certified to the 61326 EMC standards do well against my tests.  The protection is a dice roll as what it even means.  Protect the meter, protect the operator, both...   Manufactures don't agree.   I was interested in finding meters that would not be damaged when subjected to a few basic transients.  It doesn't really fit with the IEC standards and why I rolled my own generator.   I wanted something like the 6100-4-5 surge but limited.  So I dropped the combo,  followed the open circuit voltage waveforms, ignored the short circuit current and limited it to about 20J.   Depending on the generator, I used a 50 or 100us FWHH and stayed with a 2 ohms source across the board.   

We did have a member how stepped up and ran a new Fluke 101 on a real combo generator after I tested that first one.  Crazy how robust these things are.  That was Fungus's contribution as I would have never purchased another Fluke otherwise as I was still pissed at them a few decades later for designing such a weak meter (8000A).   :-DD

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Have you got any plans to torture test any bench meters? Unless I missed it I haven't seen any so far from you. I'd be really curious to see what you find
Fungus:

--- Quote from: switchabl on April 25, 2023, 10:10:52 pm ---b) Yes, anyone repairing or developing mains-powered electronics or appliances will usually need CAT II only (CAT III is for electricians).

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OK, let's say I'm working on a PC power supplies in a large office building. How can I know for sure if the mains on my workbench is CAT II or CAT III? Am I supposed to trace the wires in the walls back to the distribution panel and measure how long they are before deciding what meter to use? That's the only way to follow the standard.

Let's suppose it's a company with a few different rooms with workbenches. Will all those rooms have the same CAT rating?

Should a professional or a company like that even make the effort to source/purchase CAT II meters? What would be the advantage? What brand/model would you advise them to buy?
IanB:

--- Quote from: David Aurora on April 26, 2023, 02:20:41 am ---Have you got any plans to torture test any bench meters? Unless I missed it I haven't seen any so far from you. I'd be really curious to see what you find

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Are bench meters supposed to be robust? In my mind I think of them as sensitive, delicate, precision instruments, things to be treated with care. Would you expect an expensive Mitutoyo micrometer to survive being chucked in a tool drawer?
Someone:

--- Quote from: Fungus on April 26, 2023, 03:56:58 am ---
--- Quote from: switchabl on April 25, 2023, 10:10:52 pm ---b) Yes, anyone repairing or developing mains-powered electronics or appliances will usually need CAT II only (CAT III is for electricians).
--- End quote ---
OK, let's say I'm working on a PC power supplies in a large office building. How can I know for sure if the mains on my workbench is CAT II or CAT III? Am I supposed to trace the wires in the walls back to the distribution panel and measure how long they are before deciding what meter to use? That's the only way to follow the standard.

Let's suppose it's a company with a few different rooms with workbenches. Will all those rooms have the same CAT rating?

Should a professional or a company like that even make the effort to source/purchase CAT II meters? What would be the advantage? What brand/model would you advise them to buy?

--- End quote ---
Sounds identical to the grumbling in another recent low cost multimeter thread: https://www.eevblog.com/forum/testgear/aneng-sz20-25-000-count-1uv-10na-20a/
Is it plugged into a mains socket outlet, but lacks at least 1 form of isolation? You're in CAT II land.

Someone else has done the hard work and figured out the probability of seeing something outside of CAT II at a mains outlet is vanishingly improbable (assuming everything upstream of there is installed to your prevailing standards). Broad categories that encompass close to worst case conditions.
EEVblog:
BTW, the DT830 meter was designed by Li Hong in 1984, the founder of Zotek, as per my recent video.
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