Poll

Are you interested in seeing more handheld meters tested?

This testing is pointless! Please STOP damaging these meters!
3 (6.4%)
 Yes, I would like to more meters tested.
44 (93.6%)

Total Members Voted: 47

Author Topic: Handheld meter robustness testing  (Read 638384 times)

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Offline GuidoK

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Re: Handheld meter electrical robustness testing.
« Reply #3700 on: July 12, 2020, 01:34:33 am »
Is the DT-9561 UL listed?  I was looking on the Amazon ad and in the manual they link and did not see where it was certified.  The manual claims it meets UL... but there is no report number.
You're right, that was an assumption of mine. I looked in the manual where they say it meets UL so I figured it was UL listed, but I haven't actually seen a report number or testing agency on the back of the 90DM610 (the pics on the amazon listing are generic pics)

Quote
   Looking at the higher priced meter, I don't see a report number.     Their pictures are not clear enough to see a UL mark.
No indeed it's not in the manual, but in the kiss analog video an Intertek logo and file number can be seen:
https://youtu.be/wfFG8v-RPQ8?t=516
Intertek 4007177 if my eyesight is right

I looked it up and that report number does nothing in the intertek database, but the modelnumbers DT-9560/9561/9562 do.
You get some shenzen corporation but at the trade names it says (among others) CEM and the DT-9560/9561/9562 are compliant to some standards
https://ramuk.intertekconnect.com//WebClients/ITS/DLP/products.nsf/vwSearch?SearchView&Query=FIELD%20ListHead%20Contains%20DT-9562%20or%20FIELD%20CatCode%20Contains%20DT-9562%20or%20FIELD%20Title%20Contains%20DT-9562%20or%20FIELD%20ProductInformation%20Contains%20DT-9562%20or%20FIELD%20ProductInfo%20Contains%20DT-9562&SearchOrder=1&SearchMax=1000&SearchWV=FALSE&SearchThesaurus=FALSE&SearchFuzzy=FALSE

True the amazon commercial name is not present in that list but it's pretty certain they're rebranded CEM's so I guess they are both UL listed.
My guess is the 90DM610 will have an intertek stamp on the back just as the 90DM600 has.

I have no idea why they print that number on it when it doesn't work in the intertek database and also isn't mentioned in the listings you get there.
Maybe there is more to it than what consumers can see. I have no idea how these systems work. My teacher is google here....
« Last Edit: July 12, 2020, 01:43:12 am by GuidoK »
 
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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3701 on: July 12, 2020, 02:49:07 am »
The 121GW was certified by ETL as well.   After seeing that meter pass their certification while not being able to perform a simple autorange, I have low confidence in their abilities.   

I can tell you that when I watching him open that meter up I thought, I wonder how those piss ant fuses handle CATIV fault currents at 1KV DC....   

The Brymen BM869s on the other hand actually has a UL listing.   Those large HRC fuses are not their for the fun of it. 

Personally, for me it makes little difference.  If I have to work in an industrial environment, I am not using a cheap meter.   

As I have said many times, for my low energy electronics experiments, I am far more interested in if a meter will survive some simple transients than if it is safe.   Basically, it was the whole point of this thread.   

I think we both agree now that they are made by CEM.  If you would like to see how one would stack up in my testing against all the other meters I have looked at, knowing it has nothing to do with safety,  I may pick one up at some point.   For me, it's just another CEM with the similar clamp scheme as the ones I have looked at. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline GuidoK

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Re: Handheld meter electrical robustness testing.
« Reply #3702 on: July 12, 2020, 04:03:05 am »
The 121GW was certified by ETL as well.   After seeing that meter pass their certification while not being able to perform a simple autorange, I have low confidence in their abilities.   


With the UL 61010 not being an open norm (you have to pay dearly for it, and obviously I'm to cheap for that  ;D), I don't really know what's in there, so I don't know if it's a matter of abilities or a matter of that the content and demands set out in the norm have any real competence or high set standards of quality in them.  I also don't know if its standards concerning safety or robustness or whatever; I think its mostly (all?) safety stuff, so I imagine they want to see double isolation, isolation values of the casings and such. Maybe that's why a non/bad functioning meter can perfectly pass that norm.

All I know is that DMM reviewers usually point it out if the DMM has it or not when they review a DMM.

Browsing through the Intertek database I also saw that the popular Uni-T UT-61e is UL listed. Apparently that also meets UL 61010 standards. That immediately shows that the UL61010 standard at least isn't of much use for the gas grill repair man  ;D :palm:

And in the Uni-Trend listings you can then also see that Uni-T makes products for amongst others AMPROBE, EXTECH, GRAINGER, GREENLEE, KLEIN TOOLS,  MILWAUKEE, TENMA, Southwire, VOLTCRAFT,  and BOSCH. Always interesting to see that (but not really unheard of of course)

The inside input protection of the Amazon Commercial 90DM600 as reviewed by Kiss Analog certainly looks similar with it's arrangement of PTC's and MOV's to the CEM DT9939 you've tested so indeed maybe it performs similar on that aspect.
« Last Edit: July 12, 2020, 04:34:42 am by GuidoK »
 

Offline sequoia

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Re: Handheld meter electrical robustness testing.
« Reply #3703 on: July 12, 2020, 05:12:28 am »
Whether 90DM600 and 90DM610  are the same I don't know. Opening them up can only provide the answer ;).
I think specs and functionality from the manual are the same I believe for what I've seen.

I haven't seen 90DM610, but have played with the 90DM600 (those used to sell about $30-$40 couple months ago....Amazon pricing is grazy)

https://www.eevblog.com/forum/testgear/amazon-commercial-90dm600-multimeter-hacks/

It would seem these are pretty much identical meters except the rotary switch has one more position on 90DM610, while 90DM600 likely is otherwise exact same meter...

Some photos including photo of the Intertek logo/number can be found here:
https://www.eevblog.com/forum/testgear/amazon-do-multimeters-now/msg3040260/#msg3040260

« Last Edit: July 12, 2020, 05:17:49 am by sequoia »
 
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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #3704 on: July 12, 2020, 01:33:48 pm »
The 121GW was certified by ETL as well.   After seeing that meter pass their certification while not being able to perform a simple autorange, I have low confidence in their abilities.   


With the UL 61010 not being an open norm (you have to pay dearly for it, and obviously I'm to cheap for that  ;D), I don't really know what's in there, so I don't know if it's a matter of abilities or a matter of that the content and demands set out in the norm have any real competence or high set standards of quality in them.  I also don't know if its standards concerning safety or robustness or whatever; I think its mostly (all?) safety stuff, so I imagine they want to see double isolation, isolation values of the casings and such. Maybe that's why a non/bad functioning meter can perfectly pass that norm.

All I know is that DMM reviewers usually point it out if the DMM has it or not when they review a DMM.

Browsing through the Intertek database I also saw that the popular Uni-T UT-61e is UL listed. Apparently that also meets UL 61010 standards. That immediately shows that the UL61010 standard at least isn't of much use for the gas grill repair man  ;D :palm:

And in the Uni-Trend listings you can then also see that Uni-T makes products for amongst others AMPROBE, EXTECH, GRAINGER, GREENLEE, KLEIN TOOLS,  MILWAUKEE, TENMA, Southwire, VOLTCRAFT,  and BOSCH. Always interesting to see that (but not really unheard of of course)

The inside input protection of the Amazon Commercial 90DM600 as reviewed by Kiss Analog certainly looks similar with it's arrangement of PTC's and MOV's to the CEM DT9939 you've tested so indeed maybe it performs similar on that aspect.

Odd ETL would have the UL database.  Are you sure that what you saw wasn't ETL testing the UT61E to the UL standards?  A big difference between that and having UL list it.  The more I see approved from ETL, the less I trust them for meter safety certifications.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline GuidoK

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Re: Handheld meter electrical robustness testing.
« Reply #3705 on: July 12, 2020, 02:29:41 pm »

Odd ETL would have the UL database.  Are you sure that what you saw wasn't ETL testing the UT61E to the UL standards? 

You're right again. I'm looking in the Intertek database. I don't know how to look in the UL database. Didn't realize that's not the same thing, but makes sense.
So it's Intertek tested UL 61010 compliant.
And I think that also goes for the amazon commercial meters and CEM meters.

 I don't know if Intertek can be trusted for safety certifications. I guess it all depends on what exactly is written in that safety certification.
If the things written in UL 61010 are not up to the standards/expectations you have when torture testing the meters to begin with, then it's not very useful to begin with. Have you a specific feature of the UL 61010 in your mind that Intertek does not check/check properly that makes you come to your opinion that ETL or Intertek can't be trusted?

Edit:
I registred at UL and have now some acces to their database.
UT61e isn't listed, but it's predecessor, the UT-60A/B/C/D is.
Looking at the internals of the UT-60, that also looks like it doesn't have a whole lot of input protection & glass fuses:
https://oliversmith.io/technology/2009/12/27/inside-the-uni-t-ut60a-multimeter/
Maybe you can make more of it.
So I don't know if it's specifically an Intertek/ETL thing or that the UL 61010 isn't that high of a standard.
« Last Edit: July 12, 2020, 03:29:32 pm by GuidoK »
 

Online joeqsmith

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Re: Handheld meter robustness testing
« Reply #3706 on: July 12, 2020, 03:46:19 pm »

Odd ETL would have the UL database.  Are you sure that what you saw wasn't ETL testing the UT61E to the UL standards? 

You're right again. I'm looking in the Intertek database. I don't know how to look in the UL database. Didn't realize that's not the same thing, but makes sense.
So it's Intertek tested UL 61010 compliant.
And I think that also goes for the amazon commercial meters and CEM meters.

 I don't know if Intertek can be trusted for safety certifications. I guess it all depends on what exactly is written in that safety certification.
If the things written in UL 61010 are not up to the standards/expectations you have when torture testing the meters to begin with, then it's not very useful to begin with. Have you a specific feature of the UL 61010 in your mind that Intertek does not check/check properly that makes you come to your opinion that ETL or Intertek can't be trusted?

Again, I am not trying to prove if the meters are safe.  You should take the time to read the FAQ.   The link is in the very first post.   Yes, there are things that IMO  the standards are lacking but again, I am not an expert in safety.   I've sited several examples over the years.   

If the standards don't for example consider a strong magnetic field like you may have with a magnetic hanger you would typically use in an industrial setting and a handheld meter uses latching relays that can change their state just from having the magnet pass too close to them and the designers have no feedback to know what state they are in, and this causes the meter to indicate to the operator  safe levels  rather than potentially lethal levels....  I don't need a government agency that is behind the times to tell me there is a safety problem.   

If the standards don't consider that a handheld meter's autorange may not function properly and that the meter could indicate to the operator safe levels rather than potentially lethal ones......

There are people on this site like yourself, who have an interest in DMM safety.   You may want to try posting the question in
the following thread:

https://www.eevblog.com/forum/testgear/a-list-of-multimeters-that-do-not-appear-to-meet-their-claimed-safety-specs/

I imagine there are forums dedicated to safety testing, for example IEEE.  That may be something for you to look into. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline GuidoK

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Re: Handheld meter robustness testing
« Reply #3707 on: July 12, 2020, 04:00:34 pm »

Again, I am not trying to prove if the meters are safe.  You should take the time to read the FAQ.   
I know you're not trying to prove if the meters are safe, but you specifically write about your opinion on the integrity of Intertek/ETL organisation compared to UL, and I wonder if that makes sense or not (nofi) where it say would be different if UL had tested them or whether the UL norm (UL61010) itself doesn't meet your expectations.
Is non functioning autorange or being influenced by magnetic sources tested? (in any norm?). Maybe your expectations and assesmentcriteria of the concept of safety are way higher than is set out in these norms (they might form a very poor baseline to begin with; it's all a matter of how one's own expecations are).

 

Online joeqsmith

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Re: Handheld meter robustness testing
« Reply #3708 on: July 12, 2020, 04:44:55 pm »

Again, I am not trying to prove if the meters are safe.  You should take the time to read the FAQ.   
I know you're not trying to prove if the meters are safe, but you specifically write about your opinion on the integrity of Intertek/ETL organisation compared to UL, and I wonder if that makes sense or not (nofi) where it say would be different if UL had tested them or whether the UL norm (UL61010) itself doesn't meet your expectations.
Is non functioning autorange or being influenced by magnetic sources tested? (in any norm?). Maybe your expectations and assesmentcriteria of the concept of safety are way higher than is set out in these norms (they might form a very poor baseline to begin with; it's all a matter of how one's own expecations are).

Again it seems worth repeating for you:
"Yes, there are things that IMO  the standards are lacking but again, I am not an expert in safety."

If I start seeing what I consider are safety related problems with UL certified meters, I will certainly make note of them.   

I would imagine it's like any job and the experience and knowledge of the staff are going to have a big influence on the end product.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Fungus

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Re: Handheld meter robustness testing
« Reply #3709 on: July 12, 2020, 04:47:21 pm »
IIRC Batteroo got (bought?) themselves a UL certificate that UL ought to be ashamed of.

I think they probably do a good job on the whole though.

Is non functioning autorange or being influenced by magnetic sources tested? (in any norm?).
UL documents cost thousands of $$$ to read, I'm not sure anybody here has actually read the complete standard.

https://standardscatalog.ul.com/ProductDetail.aspx?productId=UL61010-1

I believe the standard only refers to meter electricral breakdowns though. They want to know if the meter can create an arc flash and hurt you, they aren't concerned with the accuracy or reliability of the readings on the screen.

(please correct me if I'm wrong about that)

Seasoned electricians use cheap light bulbs to check for presence of lethal voltages, not fancy mulltimeters. Carry a battery pack with you to check the bulb is good before and after you test the circuit. KISS.

« Last Edit: July 12, 2020, 04:52:00 pm by Fungus »
 

Offline Caliaxy

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Re: Handheld meter electrical robustness testing.
« Reply #3710 on: July 12, 2020, 04:49:11 pm »
Whether 90DM600 and 90DM610  are the same I don't know. Opening them up can only provide the answer ;).
I think specs and functionality from the manual are the same I believe for what I've seen.

I haven't seen 90DM610, but have played with the 90DM600 (those used to sell about $30-$40 couple months ago....Amazon pricing is grazy)

https://www.eevblog.com/forum/testgear/amazon-commercial-90dm600-multimeter-hacks/

It would seem these are pretty much identical meters except the rotary switch has one more position on 90DM610, while 90DM600 likely is otherwise exact same meter...

Some photos including photo of the Intertek logo/number can be found here:
https://www.eevblog.com/forum/testgear/amazon-do-multimeters-now/msg3040260/#msg3040260

I do own 90dm610 and can confirm that the markings on the back (referring to UL and Intertek standards) are identical to the ones on the back of 90dm600 as shown in sequoia's pictures.

Currently 90dm610 is $49 and 90dm600 is $86.18 (on Amazon USA). Yes, crazy prices (still have to figure Amazon's pricing strategy....)
 

Online joeqsmith

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Re: Handheld meter robustness testing
« Reply #3711 on: July 12, 2020, 05:40:40 pm »
I registred at UL and have now some acces to their database.
UT61e isn't listed, but it's predecessor, the UT-60A/B/C/D is.
Looking at the internals of the UT-60, that also looks like it doesn't have a whole lot of input protection & glass fuses:
https://oliversmith.io/technology/2009/12/27/inside-the-uni-t-ut60a-multimeter/
Maybe you can make more of it.
So I don't know if it's specifically an Intertek/ETL thing or that the UL 61010 isn't that high of a standard.

I would imagine it's possible for a company to have a product certified then change the design to where it would no longer pass.   Changing to a lower cost component to save money for example.    I would imagine that it's possible to have an autorange function be tested, then change the firmware and have it behave differently.   Lots of things to consider when you talk about safety. 

I believe the standard only refers to meter electricral breakdowns though. They want to know if the meter can create an arc flash and hurt you, they aren't concerned with the accuracy or reliability of the readings on the screen.

(please correct me if I'm wrong about that)


I would say you are wrong but again, I am not an expert.  Consider these two sections:

Quote
If a HAZARD could arise from an OPERATOR'S reliance on the value (for example, voltage) displayed by the equipment, the display shall give an unambiguous indication whenever the value is above the maximum positive value or below the minimum negative value of the range to which the equipment is set.

Quote
After the voltage of ..... has been applied to the METER, the METER shall continue to be
able to indicate the presence of HAZARDOUS LIVE voltages up to the maximum RATED voltage.

 Now do they need to be told that if the meter displays 1V when 1KV was applied after the magnetic strap was held next to it that it's a problem?  Maybe.  Do they need to be told to test for odd behaviors in the autorange?  Maybe.   Who's fault is it if they don't stumble onto a case that causes an unsafe condition?  The test house?  The body in charge of the standards?  The company who produced the product?  The designer?  The idiot in marketing that wanted the stupid feature?    I guess you get someone killed or injured and let the courts sort it out. 

I would say if you're a company and throwing your product over the wall to be tested, you're fools.     

Seasoned electricians use cheap light bulbs to check for presence of lethal voltages, not fancy mulltimeters. Carry a battery pack with you to check the bulb is good before and after you test the circuit. KISS.

I would suggest electricians, like everyone else, are not all working at the same level or on the same problems.   Their choice of tools may depend on the job requirements.   

Imagine an industrial electrician with their light bulb.... nah...   The meter I use is about $10,000 and can provide a bit more detail than a light bulb.

******
Thinking about negligence,
Say we have some product that was certified.  Everything is great.   Someone hacks the firmware and makes it available to the public.  Say they were not the brightest bulb in the fixture and their changes make the device unsafe.   Some time later, someone is killed or injured due to installing these changes.   Who is a fault?  The company making the meter?  The person who hacked the meter?  The person who installed the hack?   Maybe the person who installed the hack was some beginner who didn't know any better and they loaned the meter to the person who was harmed.   Does that get them off the hook?
« Last Edit: July 12, 2020, 06:05:47 pm by joeqsmith »
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Offline Fungus

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Re: Handheld meter robustness testing
« Reply #3712 on: July 12, 2020, 05:53:53 pm »
I believe the standard only refers to meter electricral breakdowns though. They want to know if the meter can create an arc flash and hurt you, they aren't concerned with the accuracy or reliability of the readings on the screen.

(please correct me if I'm wrong about that)


I would say you are wrong but again, I am not an expert.  Consider these two sections:

Quote
If a HAZARD could arise from an OPERATOR'S reliance on the value (for example, voltage) displayed by the equipment, the display shall give an unambiguous indication whenever the value is above the maximum positive value or below the minimum negative value of the range to which the equipment is set.

Quote
After the voltage of ..... has been applied to the METER, the METER shall continue to be
able to indicate the presence of HAZARDOUS LIVE voltages up to the maximum RATED voltage.

OK, I'll go with wrong.

I'm not sure how to interpret "the range to which the equipment is set" in the case of an autoranging meter though.

I also don't know how they can certify 100% that there's no software bugs in the autoranging process.

 

Online joeqsmith

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Re: Handheld meter robustness testing
« Reply #3713 on: July 12, 2020, 06:20:30 pm »
I believe the standard only refers to meter electricral breakdowns though. They want to know if the meter can create an arc flash and hurt you, they aren't concerned with the accuracy or reliability of the readings on the screen.

(please correct me if I'm wrong about that)


I would say you are wrong but again, I am not an expert.  Consider these two sections:

Quote
If a HAZARD could arise from an OPERATOR'S reliance on the value (for example, voltage) displayed by the equipment, the display shall give an unambiguous indication whenever the value is above the maximum positive value or below the minimum negative value of the range to which the equipment is set.

Quote
After the voltage of ..... has been applied to the METER, the METER shall continue to be
able to indicate the presence of HAZARDOUS LIVE voltages up to the maximum RATED voltage.

OK, I'll go with wrong.

I'm not sure how to interpret "the range to which the equipment is set" in the case of an autoranging meter though.

I also don't know how they can certify 100% that there's no software bugs in the autoranging process.

The first is in the case of an over-range.  My interpretation is they want the person conducting the test to drive the meter beyond it's maximum to make sure the meter still displays some maximum value, or a warning.    Say for example you have a 1KV rated meter.  You don't want to be on say the 200V range, apply 440V and the meter displays 0V.  You expect it to read over range, to needle hammers to the dead stop, maybe it has a red LED indicating there is a some potential hazard.

Yes, that's partly my point.  Who's job is it to prove the functionality of a product and when something is missed who is at fault?   If the company knew of a fault, say for example, I knew the 121 had some problem and disclosed it and say that information was not passed onto the test house.   Does this change the game?  Who knows.   As little as I know about safety, I know even less about US law.  The DMM is a safety device.  I assume most working in this environment have the training and PPE to keep them safe regardless.  So it may not get tested in the courts.  Still.....
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online joeqsmith

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Re: Handheld meter robustness testing
« Reply #3714 on: July 12, 2020, 06:49:21 pm »
For you safety minded people,  this is a good video describing an electrician involved with an arcflash.   

https://www.youtube.com/watch?time_continue=454&v=hfnEuRA7-vo&feature=emb_logo
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online joeqsmith

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Re: Handheld meter robustness testing
« Reply #3715 on: July 12, 2020, 08:40:50 pm »
Whether 90DM600 and 90DM610  are the same I don't know. Opening them up can only provide the answer ;).
I think specs and functionality from the manual are the same I believe for what I've seen.

I haven't seen 90DM610, but have played with the 90DM600 (those used to sell about $30-$40 couple months ago....Amazon pricing is grazy)

https://www.eevblog.com/forum/testgear/amazon-commercial-90dm600-multimeter-hacks/

It would seem these are pretty much identical meters except the rotary switch has one more position on 90DM610, while 90DM600 likely is otherwise exact same meter...

Some photos including photo of the Intertek logo/number can be found here:
https://www.eevblog.com/forum/testgear/amazon-do-multimeters-now/msg3040260/#msg3040260

I do own 90dm610 and can confirm that the markings on the back (referring to UL and Intertek standards) are identical to the ones on the back of 90dm600 as shown in sequoia's pictures.

Currently 90dm610 is $49 and 90dm600 is $86.18 (on Amazon USA). Yes, crazy prices (still have to figure Amazon's pricing strategy....)

Are all the specs the same except for the addition of the temperature sensor?   

I had seen their post a while back showing the markings and had made a few comments about running one at that time but there seemed to be little interest. 

https://www.eevblog.com/forum/testgear/amazon-do-multimeters-now/msg3040260/#msg3040260

One thing you can be sure of is that my test jigs won't care how popular a meter is or how people feel about what see when they look at them.    Saying "that's a lot of protection"  is not magically going to make it do well. 

https://youtu.be/wfFG8v-RPQ8?t=2580 

If you would like to see one ran, just let me know.
« Last Edit: July 12, 2020, 08:44:05 pm by joeqsmith »
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Offline CDaniel

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Re: Handheld meter robustness testing
« Reply #3716 on: July 13, 2020, 01:56:47 pm »
It looks like a 50$ meter , it is funny how easily people compare them to a Fluke  ;D
 

Online joeqsmith

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Re: Handheld meter robustness testing
« Reply #3717 on: July 14, 2020, 12:22:16 pm »
It looks like a 50$ meter , it is funny how easily people compare them to a Fluke  ;D
I compare them all against one another.  Blue, red, yellow, black... CE, TUV, CSA, UL... CATIII, IV,  $free, $900,  none of it matters.   Few survive, some can be repaired, most are recycled.

More to your point, Fluke no mater where they were produced, have made some of the most robust meters I have looked at.   Something I would have never guessed based on my very first Fluke meter that was a little princess.    Having ran so many Brymen products, it is obvious they also know how to make very robust meters.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline CDaniel

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Re: Handheld meter robustness testing
« Reply #3718 on: July 14, 2020, 05:28:18 pm »
My post was for that "review" youtube video , not  about your tests   ;D
 

Online joeqsmith

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Re: Handheld meter robustness testing
« Reply #3719 on: July 14, 2020, 10:56:01 pm »
My post was for that "review" youtube video , not  about your tests   ;D

Most of the ones I see, they just take it out of the box and talk about how great they are.  This is normally preceded by them telling you what an expert they are in some field.    :-DD 
 

People have been concerned with damaging their meters as long as there have been meters.  Here's an article from the 50s.   Note, they don't seem to care about safety. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online Kosmic

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Re: Handheld meter robustness testing
« Reply #3720 on: July 15, 2020, 12:18:32 am »
People have been concerned with damaging their meters as long as there have been meters.  Here's an article from the 50s.   Note, they don't seem to care about safety.

They were definitely not worried about safety. Got a old analog Triplett multimeter with a 6kV range.



They simply put 2 x 24M resistors in series with the input mounted on some super small connectors.

 

Offline IanB

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Re: Handheld meter robustness testing
« Reply #3721 on: July 15, 2020, 12:21:42 am »
People have been concerned with damaging their meters as long as there have been meters.  Here's an article from the 50s.   Note, they don't seem to care about safety.

From the title of "Six-Bit Meter Saver" we can assume that two silicon diodes at that time cost about 75 cents? Interesting as that would be about $7 in today's money. Not much different than the cost of an HRC fuse.
I'm not an EE--what am I doing here?
 

Offline dcac

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Re: Handheld meter robustness testing
« Reply #3722 on: July 15, 2020, 12:28:48 am »
I came to think of this 'safety' note in my dad's old Heathkit IM28 manual  - I think that design was from late 60s.

[attach=1]

 
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Offline CDaniel

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Re: Handheld meter robustness testing
« Reply #3723 on: July 15, 2020, 07:18:19 am »
That meter is powered from mains and uses the "clasic" setup with the earth mains conected to chassis and ground ... like any new bench scope that will go boom if you touch the probe ground clip to a live wire
« Last Edit: July 15, 2020, 07:22:03 am by CDaniel »
 

Offline GuidoK

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Re: Handheld meter robustness testing
« Reply #3724 on: July 16, 2020, 06:14:44 am »
like any new bench scope that will go boom if you touch the probe ground clip to a live wire
Wouldn't just the earth leakage breaker circuit/RCDO just trip?
What's that.... 30mA or so? Can that cause a 'boom'?
« Last Edit: July 16, 2020, 06:49:06 am by GuidoK »
 


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