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 636935 times)

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Offline Lightages

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I am 100% surprised that the 87V did not survive the same treatment as the 101.
 

Offline mtdoc

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I agree, if people want a robust meter, they should spend $50 on the 101 and not $400 on the 87V.   

But what if someone wants a robust full featured meter?   Agreed that based on your testing the Fluke 101 appears to be a very robust pocket meter. I think your testing surprised a lot of people on how robust that little meter is. But its features are limited.

As I said before, I agree that $400 is too much for an 87V , but what else with its feature set matches its build quality and accuracy?  One of the Brymens maybe?

« Last Edit: July 11, 2015, 05:16:49 am by mtdoc »
 

Online joeqsmith

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I have no interest in doing such testing myself.
And why does this not surprise me??

Quote
Is one not allowed to comment or point out limitations of a test? 
Pointing out what I have already pointed out is pointless but if you feel there is a point to it pointing, point away...  :blah: :blah: :blah:

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Yes, you have stated many of the limitations yourself but you also repeatedly make generalized conclusions based on the tests which I find unjustified. 

I agree, if people want a robust meter, they should spend $50 on the 101 and not $400 on the 87V.   

But what if someone wants a robust full featured meter?   Agreed that based on your testing the Fluke 101 appears to be a very robust pocket meter. I think your testing surprised a lot of people on how robust that little meter is. But its features are limited.


This must be one of my repeated generalized conclusions you mentioned.   If you are asking for a recommendation,  I don't have one.  As lightages and others have stated many times, there is more to picking a meter than just one metric.     I do agree on your comment about the 101 having limited features and will go one step further and say all handled meters have very limited features!   Hello, that's why I have more than hand held meters to play with!   Dang, you are right!  Everything I seem to post IS generalized!   :-DD   

Quote
My point was that only a failure at a lower voltage with arcing or something of danger to the user would present any meaningful knock on the 87V's  "robustness".

Do you think when the backs blow off the devices, there's no arc?   Do you think if an arc is small, it presents no risk of danger?   Do you think if an arc is small that there is no chance that it can grow?   

Again, you may want to consider there was no line voltage to sustain an arc for a reason.

There is no way I would trust my life with the 87V.  That may seem like an unfair comment to a few of you but again, as so many of you have pointed out, what is my life worth.  It sure seems like there were a few that were quick to point out that spending more money buys safety.   Well my life is worth a lot more to me than risking it with a meter that I know fails at a lower energy than a $50 meter.

I am 100% surprised that the 87V did not survive the same treatment as the 101.

We may not always see eye to eye but in this particular case I am right there beside you!!  I was floored.  But this is why we run the tests.    I would really enjoy having someone repeat a test like this with a brand new 101 and an 87V.   We have one other member with a real IEC generator.   Who knows, that 87V may just fail at 12KV, 50us FWHH.    Maybe a few of you could help defer the cost if they offered to run it.   The nice thing about going that route is then anyone could repeat this test using a standard generator.   They can also increment the voltage as they did with the 101.  If it does fail, it may provide some insight at what level.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Muxr

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...
101 sure impressed, but I was also impressed by the Amprobe 510 which failed from much less of a transient than 87V. In fact your tests made me recommend it to a few people. I think it's a great little meter for someone just starting. That's the perspective I am coming from, not some spin.

Your poor experience with a 40 year old Fluke bench meter certainly stands but that's a bit apples and oranges comparison. Great progress has been made in almost every aspect of electronic design and manufacturing since then. 4-6 layer PCBs, components with built in protection, more focus on safety, CAT safety standards... the list goes on. I think back then the DMM industry was still trying to pull of a working DMM design off the ground, and they were still coming up with features we take for granted today. It's a bit unfair to paint today's products on account of shortcomings of products from 40 years ago.

Also 13Kv is nothing to sneeze at. That's quite a bit more of a transient than what all the meters that failed next to 101 were subjected to.

87V survived that same 13Kv zap in all the modes but the Ohm mode. I think that's pretty darn good. It's well beyond the CAT IV spec, which doesn't even cover wrong modes.

I think 87V did well. Not as impressive as 101 but still pretty good. I got both meters. 101 is a cool little meter, but it's not at all in the same league in terms of usability as the 87V.

I could not rely on a Fluke 101 as my main meter as it simply lacks essential features. First one being the lack of a tilting bail. But thanks to all your awesome efforts now I know  87V can safely survive 13Kv transients, provided I use the right mode  :)
 

Offline mtdoc

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Wow Joe.  Have a beer or something....

Well said Muxr. I agree.
« Last Edit: July 11, 2015, 06:33:26 am by mtdoc »
 

Online joeqsmith

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Quote
Your poor experience with a 40 year old Fluke bench meter certainly stands but that's a bit apples and oranges comparison. Great progress has been made in almost every aspect of electronic design and manufacturing since then. 4-6 layer PCBs, components with built in protection, more focus on safety, CAT safety standards... the list goes on. I think back then the DMM industry was still trying to pull of a working DMM design off the ground, and they were still coming up with features we take for granted today. It's a bit unfair to paint today's products on account of shortcomings of products from 40 years ago.

Once bitten twice shy.   Fool me once shame on you, fool me twice shame on me.   That first impressions are hard to erase!

101 sure impressed, but I was also impressed by the Amprobe 510 which failed from much less of a transient than 87V.

Also 13Kv is nothing to sneeze at. That's quite a bit more of a transient than what all the meters that failed next to 101 were subjected to.

87V survived that same 13Kv zap in all the modes but the Ohm mode. I think that's pretty darn good. It's well beyond the CAT IV spec, which doesn't even cover wrong modes.

I think 87V did well. Not as impressive as 101 but still pretty good. I got both meters. 101 is a cool little meter, but it's not at all in the same league in terms of usability as the 87V.

... now I know  87V can safely survive 13Kv transients, provided I use the right mode  :)


You are twisting the data which is a bad thing for people reading the posts. 
Quote
...the Amprobe 510 which failed from much less of a transient than 87V.
Of course, the AMPROBE was tested from the beginning, the 87V was not tested until the end.    The 87V was never tested at lower voltages so we do not know where it fails.    It may have failed at 2KV.  We don't know.   

You brought up the AMPROBE.  So lets consider that meter.   It made it all the way into the finals where they were tested with a 5.8KV peak,  5us FWHH, 2 ohm source.   When it failed it would still measure voltage just like the 87V.    Consider that the AMPROBE could have continued to read voltages all the way up to 13KV as well.  Again, we don't know.   I didn't care as it had failed.   

And what failed on the UNI-T UT90A?  Again, the voltages still functioned fine. 

Had I waited until the end to test the UNI-T and the AMPROBE, they too would have failed at 13KV.  That does not mean they were more robust than the other meters. 

Don't twist the data to fit your desired outcome. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Muxr

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I am not "twisting any data". Fluke 87V didn't fail at 3Kv, it wasn't tested at it. But we know for sure that UT and Amprobe failed at 3Kv.

Given the experience with Fluke meters [made in this century] including the 101 I simply give it a benefit of the doubt.
 

Offline tautech

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I am not "twisting any data". Fluke 87V didn't fail at 3Kv, it wasn't tested at it. But we know for sure that UT and Amprobe failed at 3Kv.

Given the experience with Fluke meters [made in this century] including the 101 I simply give it a benefit of the doubt.
You imply the 87V failed the surge test on ohms, this is a presumption as operational checks were not done UNTIL the end of all surge tests, so who knows when/how ohms got nuked.
The fact is OHMS was nuked and to ignore this is twisting the data.
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Offline Muxr

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I am not "twisting any data". Fluke 87V didn't fail at 3Kv, it wasn't tested at it. But we know for sure that UT and Amprobe failed at 3Kv.

Given the experience with Fluke meters [made in this century] including the 101 I simply give it a benefit of the doubt.
You imply the 87V failed the surge test on ohms, this is a presumption as operational checks were not done UNTIL the end of all surge tests, so who knows when/how ohms got nuked.
The fact is OHMS was nuked and to ignore this is twisting the data.
Where did I ignore that ohms was nuked? Did I say it wasn't? Pretty sure I acknowledged it.

You seemed to have missed my point about the Ohms comment I made. It has to do with safety, let me elaborate since I understand it may not be as obvious, sorry.

Transients may happen unexpectedly. Let's say you're measuring a mains circuit and a transient nukes your voltage reading without you realizing it. You continue measuring thinking the circuit is not powered on. Can you see how dangerous this could be?

So independent of the mode the meter was in when it failed (all modes were tested), we can agree that if you're going to lose one function of a meter while dealing with high voltage circuits it is better if that function isn't related to indicating dangerous voltages. And in fact this is exactly what the CAT rating attempts to certify. As far as I know CAT doesn't deal with Ohms at all. And according to Joe's test Fluke 87V passes this aspect of it with flying colors way beyond the required rating.

As far as which mode the meter was in when the ohms got nuked we can only speculate, so there is no data to be twisted, since the meter wasn't tested between each mode.
« Last Edit: July 11, 2015, 09:06:52 am by Muxr »
 

Offline dadler

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There is no way I would trust my life with the 87V.  That may seem like an unfair comment to a few of you but again, as so many of you have pointed out, what is my life worth.  It sure seems like there were a few that were quick to point out that spending more money buys safety.   Well my life is worth a lot more to me than risking it with a meter that I know fails at a lower energy than a $50 meter.

This logic does not follow for me. Would you trust your life with the 87V if the 101 never existed, or you had never tested it?

How does the cost of one particular meter affect how much life-trustiness you would put in a different meter?

Would you trust your life to the Extech that you gave the testimonial about at the end-- the same one you said you wouldn't subject to the tests?
« Last Edit: July 12, 2015, 01:40:14 am by dadler »
 

Online joeqsmith

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There is no way I would trust my life with the 87V.  That may seem like an unfair comment to a few of you but again, as so many of you have pointed out, what is my life worth.  It sure seems like there were a few that were quick to point out that spending more money buys safety.   Well my life is worth a lot more to me than risking it with a meter that I know fails at a lower energy than a $50 meter.

This logic does not follow for me. Would you trust your life with the 87V if the 101 never existed, or you had never tested it?
As I stated before, I would not trust any meter without personally testing it.  I also have said I would never work on 440 and that I'm not trained for this.     

Quote
How does the cost of one particular meter affect how much life-trustiness you would put in a different meter?
It doesn't.

Quote
Would you trust your life to the Extech that you gave the testimonial about at the end-- the same one you said you wouldn't subject to the tests?
At most I use it to measure 220 line CAT II stuff which I do not consider high risk.   Even that is rare for the work I do.     So to answer your question, no.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline mtdoc

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There is no way I would trust my life with the 87V.  That may seem like an unfair comment to a few of you but again, as so many of you have pointed out, what is my life worth.  It sure seems like there were a few that were quick to point out that spending more money buys safety.   Well my life is worth a lot more to me than risking it with a meter that I know fails at a lower energy than a $50 meter.

This logic does not follow for me. Would you trust your life with the 87V if the 101 never existed, or you had never tested it?

How does the cost of one particular meter affect how much life-trustiness you would put in a different meter?

Would you trust your life to the Extech that you gave the testimonial about at the end-- the same one you said you wouldn't subject to the tests?


The 87V has a well deserved reputation for safety and accuracy based on experience of thousands of users over the span of almost 2 decades.  Nothing in his tests contradicts this and if anything confirms it, as Muxr pointed out.

Confirmation Bias is something that we're all susceptible to.

The 87V may be overpriced, but that is an entirely different matter.
 

Offline dadler

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There is no way I would trust my life with the 87V.  That may seem like an unfair comment to a few of you but again, as so many of you have pointed out, what is my life worth.  It sure seems like there were a few that were quick to point out that spending more money buys safety.   Well my life is worth a lot more to me than risking it with a meter that I know fails at a lower energy than a $50 meter.

This logic does not follow for me. Would you trust your life with the 87V if the 101 never existed, or you had never tested it?
As I stated before, I would not trust any meter without personally testing it.  I also have said I would never work on 440 and that I'm not trained for this.     

Quote
How does the cost of one particular meter affect how much life-trustiness you would put in a different meter?
It doesn't.

Quote
Would you trust your life to the Extech that you gave the testimonial about at the end-- the same one you said you wouldn't subject to the tests?
At most I use it to measure 220 line CAT II stuff which I do not consider high risk.   Even that is rare for the work I do.     So to answer your question, no.

Ok, thanks for the clarification. I am glad you have run these tests, they are interesting--thanks for that.

I do think you are being at best imprecise and at worst quite wishy-washy with your conclusions.

As I read your words, you are essentially concluding that since the $50 fluke did not (seemingly/immediately) fail at a specific extreme test voltage, a more expensive meter that did (seemingly/immediately) fail at the same specific extreme test voltage is not safe.

If the 87V fails in some spectacularly minor way (with a test sample of one), when subjected to conditions far exceeding its ratings, I think it is not fair to conclude that it is not a safe device--That you wouldn't "trust your life with it".

Basically, I consider your argument to be a non sequitur.
 

Online joeqsmith

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I do think you are being at best imprecise and at worst quite wishy-washy with your conclusions.

That's fine.  I thought the conclusions were pretty clear.  The Fluke 87V did not survive the same tests that I put the Fluke 101 through.

As I read your words, you are essentially concluding that since the $50 fluke did not (seemingly/immediately) fail at a specific extreme test voltage, a more expensive meter that did (seemingly/immediately) fail at the same specific extreme test voltage is not safe.

That's what you got from it?    I would not consider any meter safe which I thought would have been made very clear by now.   I guess three devices with their backs blown off would be considered "seemingly".

If the 87V fails in some spectacularly minor way (with a test sample of one), when subjected to conditions far exceeding its ratings, I think it is not fair to conclude that it is not a safe device--That you wouldn't "trust your life with it".  Basically, I consider your argument to be a non sequitur.

Argument?  You asked me specific questions, I provided you answers.    In the end, the Fluke 87V was damaged by a transient that the Fluke 101 had no problem with.   

I have no idea what safe is,  but yes, I certainly would not risk my life with the 87V measuring a 440 main but again I wouldn't risk it with the 101 which appears even more robust or any other meter out there.  Maybe this is the part you feel is irrelevant.   

Do I think using the 87V places me at a higher risk than the 101, yes because it failed at a test that the 101 survived but that risk is minimal for me because as I have stated, I don't typically work on systems where I am at exposed to lethal energy levels.   There is always my home made attenuator that I mentioned to limit the risk as well.   

I am also not going to spend hundreds on a meter that is not as robust as a $50 product so I can measure non-lethal circuits.  Nor will I spend hundreds on a meter that can't calculate AC+DC.     

Well, I hopefully cleared up a few things.      If I get another meter from Fluke or find another one that will pass the last test setup, I will post about it, otherwise I'm on to the next project.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline oldway

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These tests are interesting but do not correspond with reality.

As an engineer in power electronics, what especially interests me is what happens with the multimeter when measuring a voltage like 550VDC on a 5000A DC drive and that there is an arc in the multimeter which occurs due to a transient voltage.

When there is great power in play, things go completely differently from what is seen in this test.

The simple harmless arc turns into a real explosion.

Therefore, on one hand, high voltage transients are not interesting  because they are improbable, on the other hand, it is irrelevant whether or not the meter is still functional, what matters is that the operator has not been hurt nor killed.
 

Online Fungus

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Do I think using the 87V places me at a higher risk than the 101, yes because it failed at a test that the 101 survived

We've only seen one set of test conditions. The 101 might fail much more catastrophically than the 87V in real high-energy situations.

Bottom line: Connecting a multimeter up to a genuinely high energy device is dangerous. You need to think very carefully about how you approach it.

The best approach is not to do it at all and Waltzing up to it with a probe in either hand and the meter between your teeth isn't the way to go even if you did pay $5000 for the meter.

 

Offline oldway

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Quote
Bottom line: Connecting a multimeter up to a genuinely high energy device is dangerous. You need to think very carefully about how you approach it.

The best approach is not to do it at all and Waltzing up to it with a probe in either hand and the meter between your teeth isn't the way to go even if you did pay $5000 for the meter.
Power electronics is not a job for everyone...You must be qualified...
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Offline hibone

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why not rising the bar?

what about Cat. rated scopes?  >:D
 

Offline mtdoc

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These tests are interesting but do not correspond with reality.

As an engineer in power electronics, what especially interests me is what happens with the multimeter when measuring a voltage like 550VDC on a 5000A DC drive and that there is an arc in the multimeter which occurs due to a transient voltage.

When there is great power in play, things go completely differently from what is seen in this test.

The simple harmless arc turns into a real explosion.

Therefore, on one hand, high voltage transients are not interesting  because they are improbable, on the other hand, it is irrelevant whether or not the meter is still functional, what matters is that the operator has not been hurt nor killed.

And,

Quote
We've only seen one set of test conditions. The 101 might fail much more catastrophically than the 87V in real high-energy situations.

Excellent points oldway.  This is really the crux of the matter.  Concluding anything from one (non real world) test with one meter is folly.  Basing a decision on which of those two meters to use in a real world high energy situation based on this test is outright foolish IMO.

CAT ratings (if real!) are at least somewhat better.

I am not a power electronics engineer but I've done a fair bit of work on 240V mains and on high energy PV solar installations and I know which meter I would choose for those tasks.

 

Offline oldway

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Measuring ac and dc voltages up to 600V on high energy is an everyday task for power electronics engineer.

You need checking industrial power grid AC voltages, measuring batteries voltages of high power No breaks (up to 600V), field weakening threshold voltage (around 500V) of dc drive, and so on...

I must say I only trusted on Fluke multimeters to do that and I never had any problem.

But now, I am retired and I am not working with such dangerous voltages anymore.

Fluke 87V is a very good multimeter (I have also a 87IV, but I don't like it very much), but is far too expensive in Europe.
It should be sold for 200€, no more.

For this reason, if I would buy another multimeter, I would choose a Brymen 867's.
« Last Edit: July 12, 2015, 05:44:04 pm by oldway »
 

Offline Muxr

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I too think Brymen is a better deal 87V is overpriced for most people. But 87V is a better meter. The only reason I have a set of 87Vs though is because you can get them on Ebay for much less, due to their popularity.
 

Offline sreeb

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From a safety perspective, it unclear to me how much value there is in a test that introduces a transient without the underlying mains voltage.

My understanding, dating from some companies long ago mandatory safety training, is that the serious danger is that the transient establishes an arc and the underlying voltage sustains it.  The video tape backed this up with lots of electrical road kill photos.

I never ended up working with high power and have never experienced transient induced arcing in real life though.
 

Offline tautech

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From a safety perspective, it unclear to me how much value there is in a test that introduces a transient without the underlying mains voltage.

My understanding, dating from some companies long ago mandatory safety training, is that the serious danger is that the transient establishes an arc and the underlying voltage sustains it.  The video tape backed this up with lots of electrical road kill photos.

I never ended up working with high power and have never experienced transient induced arcing in real life though.
Welcome to the forum.

There has been much discussion on Joe's thread and techniques but it all comes down to tests that satisfy Joe, based on his past and overall exerience with DMMs so that HE is happy to use a particular brand/model.
The real outcome is a new CAT standard, Joes standard, a standard that means more to him than anyone else.

CAT joeqsmith  :-+


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Offline saturation

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Its a bit late but I hadn't the time until now to read in detail, but I suspect Fluke designs its DMM to far exceed IEC impulse test voltages to allow margin for error in production, be it component quality, to assembly.  We should consider that when producing a batch of devices, a range of performance can be expected due to parts and construction tolerances, but if the Fluke design criteria far exceeds required IEC criteria, then we can expect nearly if not all production to pass IEC criteria, with individual devices being more or less robust than a sibling. 

In the JQS video, the 87V malfunctions in ohms at 13kV, but that impulse is still above its 8kV rating and other functions appear normal.  Alas, there was no function test at under 13kV.  The Fluke educational video posted earlier in this thread shows an 87V dying at 17kV in volts mode, again far above the IEC requirement, but they did not show how well it functioned between each kV impulse test.

I think the clearest take home message is the lowly entry level Fluke 101 DMM, which appears to have only CE Fluke safety certification, no 3rd party safety certification,  is likely to take surge's well, and likely meets CAT III 600V criteria.  Chances are the 101 was designed like other Fluke DMMs, to survive far over the required IEC surge voltage.

That prompted me to search if indeed the 101 and other non-sold in the US Fluke meters have had 3rd party testing, as I noticed some 101 have a CSA mark, others do not. I found the CSA listing for the 101 and several other Fluke meters not marked CSA, which means these Flukes were tested to a point independently.  The devices made it far enough in the certification processes [safety issues] to receive a listing.  Why Fluke doesn't mark them after they've been granted a listing can be due to many speculative reasons, e.g. not paying recurring fees to keep production costs low, not completing less critical items in the CSA procedures, etc.,



I expect low.  But we can't know for sure unless we try a surge test and demonstrate it, then its not just an educated guess.  Many things can change over time and cause problems in new DMMs versus prior runs of the same model.  A test of just one meter can be criticized, but its better than nothing.

This is one reason in the past, say in the US military, samples of a procurement were tested per batch by independent military labs to insure they live up to their specification, but I don't know if they still do this.

The 87V is a defacto standard in that class DMM, so these tests will attract attention from a lot of professionals, particularly if it fails  :o
What are the chances of failure?  :-//


This is an excellent point.   I was very happy when another member took it upon themselves to run similar tests on the 101 (Well, that is until I stepped things for that last round  :-DD).  I would like to see a second 87V tested as well just so we have two data points.     Even then, that's too small of a sample size.     I'm sure Fluke already has the answer as that video made it sound like they test every design to failure. 
From what I understand from all of the posts I have read about the amount of money Fluke has invested in making their designs robust, and the 87V being a very popular meter and how long they have had to improve their designs, and again we are talking about it just doing as well as the lowest cost meter Fluke offers.  It doesn't even have to exceed it!   I assume the chances of a failure are very low.   
« Last Edit: July 16, 2015, 06:00:07 pm by saturation »
Best Wishes,

 Saturation
 

Offline saturation

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As clarification, IIRC, a transient in single phase mains voltage can propagate into an arc flash if the transient can ionizes the surrounding medium enough to reduce the impedance to allow the mains voltage to conduct.  This is were creepage, clearances and pollution degree ratings matter now, too. 

The IEC transient test is very similar as JQS demonstrates, 0V to kV and later 0 to -kV.  Its not the entire CAT test, but a key part of it. 

Quote from:  link=topic=48998.msg711016#msg711016 date=1437012934
From a safety perspective, it unclear to me how much value there is in a test that introduces a transient without the underlying mains voltage.

My understanding, dating from some companies long ago mandatory safety training, is that the serious danger is that the transient establishes an arc and the underlying voltage sustains it.  The video tape backed this up with lots of electrical road kill photos.
Best Wishes,

 Saturation
 


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