I agree, if people want a robust meter, they should spend $50 on the 101 and not $400 on the 87V.
I have no interest in doing such testing myself.
Is one not allowed to comment or point out limitations of a test?
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.
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".
I am 100% surprised that the 87V did not survive the same treatment as the 101.
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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.
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
...the Amprobe 510 which failed from much less of a transient than 87V.
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.
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.
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.
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?
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?
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.QuoteHow does the cost of one particular meter affect how much life-trustiness you would put in a different meter?It doesn't.QuoteWould 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.
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.
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
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.
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.
We've only seen one set of test conditions. The 101 might fail much more catastrophically than the 87V in real high-energy situations.
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.
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 failsWhat 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 ). 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.
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.