That's my point. The model number is exactly the same, yet the meter differs greatly in it's safety specs.Yes, I suppose that's true if the '-GS' is just an internal designation and the model that it was marketed as is just UT61E. So under the jurisdiction of the TUV, they sold one 'UT61E' with protection and lowered CAT ratings, elsewhere they depopulated the protection and increased the purported CAT ratings. I think other companies in other areas may do similar things between markets, but CAT ratings are a globally harmonized standard (or so I thought) so it does seem quite slippery of them.
With my Brymen meters that I resell under the EEVblog branding I have to have them the exact same model number BM235/BM786 and the Brymen name, otherwise if I change it they would of had to have got it entirely UL certified again which is of course lengthy and expensive process. I can't just whack another model number on it and use the UL logo and certificate for physically the exact same meter, it's that strict.
Especialy the low energy spikes will be hard to find any info about, because they don't cause imediate failure so it would be difficult to asess what would be the most common but already harmful energy and voltage level.But I think something well within Joes generators range.
You're going to have to define and quantify 'low energy' and fully specify the circuit characteristics and other test conditions for any further discussion to have meaning. I wouldn't call the jqsTM transients 'low energy'.
The 20J may be overkill but all you safety experts posting here already know where that number came from.
You may not agree but hopefully you at least now have some understanding why I will continue to call my transients low energy.
Is it because that is about the energy used in a defibrillator or because it matches up with the output of an electric fence charger (a powerful one)?
Show me a photo of a Uni-T meter, a manual, or a website link that actually has a meter labelled "UT61E-GS".
My reply #4203 has them. The meter is still labelled UT61E, but has the "GS" mark and has different CAT ratings.
That's my point. The model number is exactly the same, yet the meter differs greatly in it's safety specs and ratings.
Why would anyone trust a company that sells the exact same model number meter in different markets with different safety/protection components?
At the very least give it another model number.
With that in mind, given the mayhem your jqs IEC LiteTM transients cause, it is difficult for me to see how some of these units could emerge from the full mains-connected IEC transient test unscathed, unless the criteria being applied are just that the device not explode or trip the mains limiting.
Uni-T is doing the PCB copy'n'paste between UT61E+ and UT161E. I see the larger fuses and PTC's, PTC's moved slightly but nothing significant.
Looks like they want to charge a premium for a real 61010 product. I'll bet the BBQ lighter still makes it crash lol.
Show me a photo of a Uni-T meter, a manual, or a website link that actually has a meter labelled "UT61E-GS".
My reply #4203 has them. The meter is still labelled UT61E, but has the "GS" mark and has different CAT ratings.
That's my point. The model number is exactly the same, yet the meter differs greatly in it's safety specs and ratings.
Why would anyone trust a company that sells the exact same model number meter in different markets with different safety/protection components?
At the very least give it another model number.
So UNI-T charge a 3€ "premium" for the larger fuses and PTCs, and proper independent testing and certification for the UT161E, which as you well know, has a cost.
It still has the stupid transistor tester though. I'd never own one because of that "feature". I'd have to do a facepalm every time I turned the selector past that position on the dial.
I often ask why people continue to discuss safety in a thread that has nothing to do with it.
One would need to reread the entire thread to see how that seeped in, but I suspect the similarities of your test transient levels to the ones specified for the CAT ratings are one factor.
Anyhow, by now I agree with you, if you are referring to safety as meters exploding or arc-flash type concerns. My concerns are similar to what you have said about wanting meters to not die during normal, non-dangerous bench or other use. Transients are one way to kill them of course, but accidental overvoltage is another. I had one set of expectations about what a CAT-rating would mean about this, specifically that a meter with a CAT rating for any voltage--like a bench meter rated CAT I/1000V--would endure 1000VAC or 1000VDC on any range or input selection without damage. There's also the expectation that after the transient tests, the meter works. If those expectations on my part are wrong and the CAT ratings don't indicate performance in that regard across the board, or if different manufacturers have different standards regarding these issues, then the CAT ratings themselves are meaningless to me and of questionable value to anyone else, IMO.
If anyone wants to comment on my assertion that a CAT x/1000V meter should withstand a full 1000V on any input setting or jack, I can see about setting up a test.
Some of the smaller PTCs are only rated for 500V. Some meters have only a single PTC which if the low voltage clamp is active, will have well over 900V across them.... Maybe.... Turn the dial, I suspect you will get a light show.
Well that doesn't sound very robust! I don't know if that is a failure to meet a standard or not, but it seems like a basic expectation to me. Every CAT labelled meter I currently have that isn't known junk should pass that test. Some of them already have by accident.
Maybe start reading here. Dave chimes in. So do I.
https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1580530/#msg1580530
Is it because that is about the energy used in a defibrillator or because it matches up with the output of an electric fence charger (a powerful one)?20J is a baby fence unit these days now energisers of 60J are available:
https://pel.co.nz/en-nz/node/11974
I earlier wrote that for the extra 3€, I would rather buy the Intertek-certified UT161E rather than the UT61E+ that Joe is testing these days. The picture you posted just confirmed this.
Is it because that is about the energy used in a defibrillator or because it matches up with the output of an electric fence charger (a powerful one)?20J is a baby fence unit these days now energisers of 60J are available:
https://pel.co.nz/en-nz/node/11974
Don't take a whiz on that!
Here's a genuine CAT III 300V certified meter which has been discussed somewhere in the middle thread. It has two resistor trails leading off before anything gets to the PTC. The R31/R30/R29/R28 chain is 10MOhms, the same as the impedance of the meter in volts mode. It's not the only meter I own that's like this, hence the silly ideas in my head.
I think the input circuit is clear enough in this photo:
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I lifted up one leg of the PTC as joe suggested:
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Guess what? It still measures volts perfectly!
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OK, maybe the Fluke 101 doesn't work that way (I should have looked at the resistor values before opening my mouth) but there's definitely some certifiable meters that do work that way.
Keep those stories coming. We're here all night folks.
I'm having a moment, aren't I?I suspect you have been looking at too many low end meters like the UNI-T, ANENG.... Your statement about "...generally multimeters have a separate 10MOhm voltage input.." could be correct as I suspect there are more low end meters being introduced and sold. We love our cheap, disposable products which drives the market and I just don't want to admit it.
I am all for YOU running a test like this. I think if you want to light it up, you are going to have to use the meter incorrectly and turn the function switch with it live. If you pick a meter that I have already and find it survives, maybe I can attempt to repeat it. I have that one 121GW that was used for the majority of my destructive tests. It has been certified. I could toss that into the mix as well.
1kVDC with more than enough current to cause a major meltdown ready when you are.
Just another cheap meter. These don't surprise me but I'm interested in what your Fluke 101 does.
Just another cheap meter. These don't surprise me but I'm interested in what your Fluke 101 does...
I'm more interested in the function of that circuit than simply confirming something that's already known - science doesn't advance that way. Corrrect procedure requires a theory before I barge in and do any experiments so I need to find time to sit down and trace out the 101 PCB as the next step.
PS: The Fluke 101 is a "cheap meter". For the price of a Uni-T U61E I can get a Fluke 101 and an Aneng 870.
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I don't want to abuse the meters by switching ranges under power, just test them at max voltage on all ranges. I'll leave exploding things to others for now.
First test was a Fluke 116. You have tested a 115, I don't know if you have it still or how similar they are. I gave it 600VDC and 600VAC/100Hz in all ranges, 10-15 seconds per range, then checked its calibration afterwards. All good. I did notice that when it clamps, it can clamp a lot more current than my calibrator can supply. I had to use a different DC supply. For AC, I had to start at a lower voltage then work my way up as fast as I could push the buttons.
The next victim was actually not a handheld, but an old Fluke 8842A bench meter. No CAT rating, but it took the 1000VDC and 700VAC listed on the front panel without complaint, ohms range and all, but the calibrator started whining (literally) so I quit for the night. I'm really not looking to blow that one up.
I can toast a Harbor Freight meter for giggles, but other than that I don't have a lot to throw at it right now.
Now I need a new theory. The signal isn't used on either of the main voltage ranges and it's not for the hazardous voltage indicator.
The resistor chain goes up to the selector and is connected across to the adjacent track when the switch is in the mV/Ohms/Capacitance/Hz modes.