EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: Corner on June 26, 2020, 07:01:04 am
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Saw this meter for sale and wonder if anyone has used it and have opinions on it?
From the product page on their Taobao website, here's a few things that they claim:
- The meter can withstand 8kv transient voltage
- 1 meter drop
- rotation switch is guaranteed to still smoothly operate after 30,000 cycles
Also from the PCB image, it has two big-as Bussmann fuses and various input protection components from other good brand meters. The board looks pretty clean too.
The thing I don't see though, is independent safety certification. I'm curious if all the claims are true.
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Ugh... close, but no cigar...
Look where the current shunt is, no way that's good enough clearance for 8kV.
Don't get me wrong I like my UT139C, but if I need to measure anything dangerous, I'll reach for my Fluke 87V every time.
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I used to have a 139C as well, but I gave it to my dad. This thing functionality wise looks like a direct upgrade to the 139C.
The price is $90 AUD, I'm so tempted to get it to play around lol. God help me.
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I think it is fake.
No mention of 17 series on the Uni-trend web site.
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I think it is fake.
No mention of 17 series on the Uni-trend web site.
Are you sure? https://www.uni-trend.com.cn/index.php?m=content&c=index&a=show&catid=438&id=786 (https://www.uni-trend.com.cn/index.php?m=content&c=index&a=show&catid=438&id=786)
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Ugh... close, but no cigar...
Look where the current shunt is, no way that's good enough clearance for 8kV.
I think the cutouts and spaceings are on the other end of the fuse, where the input is. :popcorn:
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The thing I don't see though, is independent safety certification. I'm curious if all the claims are true.
If your life depends on it being true then don't trust it. Get something with a genuine certification. :-//
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I think it is fake.
No mention of 17 series on the Uni-trend web site.
Are you sure? https://www.uni-trend.com.cn/index.php?m=content&c=index&a=show&catid=438&id=786 (https://www.uni-trend.com.cn/index.php?m=content&c=index&a=show&catid=438&id=786)
Really? A 15B and a 17B? I wonder which brand they're trying to grab karma from?
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Ugh... close, but no cigar...
Look where the current shunt is, no way that's good enough clearance for 8kV.
I think the cutouts and spaceings are on the other end of the fuse, where the input is. :popcorn:
So you only get separation if the current is high enough to blow the fuse.
Great design! :-+
/sarcasm
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Ugh... close, but no cigar...
Look where the current shunt is, no way that's good enough clearance for 8kV.
I think the cutouts and spaceings are on the other end of the fuse, where the input is. :popcorn:
So you only get separation if the current is high enough to blow the fuse.
Great design! :-+
/sarcasm
LOL. Step back......
What is the voltage over shunt and fuse when fuse is not blown?
8kV? Or 100-300mV ?
8 kV limit applies to voltage mode only.
Current mode has spec of how much kV it can withstand for 1 min when fuse is blown, and that is usually 1 kV (or max voltage in voltage mode)...
Critical spec for current mode is max breaking current and fact whether it will, in fact, extinguish the plasma and break current as opposed to having a breakdown and having arc discharge accident.
Specifications are quite complicated and there are many caveats when reading what is what..
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So you only get separation if the current is high enough to blow the fuse.
Great design! :-+
/sarcasm
Ohms law says that if the voltage is high enough to jump the gap, the current will be high enough to blow the fuse.
Plus: Voltages usually only jump around when there's a high impedance in their way, which a fuse isn't.
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I think it is fake.
No mention of 17 series on the Uni-trend web site.
Are you sure? https://www.uni-trend.com.cn/index.php?m=content&c=index&a=show&catid=438&id=786 (https://www.uni-trend.com.cn/index.php?m=content&c=index&a=show&catid=438&id=786)
Really? A 15B and a 17B? I wonder which brand they're trying to grab karma from?
Reading about them on some Chinese forums, looks like they made these to directly go against Fluke 15B and 17B. Hahah! These two meters have just been released in China. It's probably going to take a little while for them to come overseas.
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So you only get separation if the current is high enough to blow the fuse.
Great design! :-+
/sarcasm
Ohms law says that if the voltage is high enough to jump the gap, the current will be high enough to blow the fuse.
Plus: Voltages usually only jump around when there's a high impedance in their way, which a fuse isn't.
That would imply that a piezo ignitor could supply enough current to blow a 10A fuse.
I suspect that would not be the case.
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So you only get separation if the current is high enough to blow the fuse.
Great design! :-+
/sarcasm
Ohms law says that if the voltage is high enough to jump the gap, the current will be high enough to blow the fuse.
Plus: Voltages usually only jump around when there's a high impedance in their way, which a fuse isn't.
That would imply that a piezo ignitor could supply enough current to blow a 10A fuse.
I suspect that would not be the case.
No, that would imply that piezo igniter connected to current input will achieve 300mV peak voltage....Because it doesn't have energy to create enough current...
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So as long as the leads are inserted in the correct sockets, you're fine.
What am I missing here?
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Some Uni-T meters have proper UL certification, but a lot (most?) don't. Seems pot luck.
But if they are competing against the Fluke then UL certification would be an absolute requirement, otherwise they are dead out of the blocks.
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For sale on ebay:
https://www.ebay.ca/itm/UNI-T-UT15B-PRO-17B-PRO-True-RMS-Digital-Multimeter-Substitute-Fluke-15B-17B/303588597896?hash=item46af4a6088:g:pwMAAOSwhBpe2xUD&var=602818694809 (https://www.ebay.ca/itm/UNI-T-UT15B-PRO-17B-PRO-True-RMS-Digital-Multimeter-Substitute-Fluke-15B-17B/303588597896?hash=item46af4a6088:g:pwMAAOSwhBpe2xUD&var=602818694809)
[attachimg=1]
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Really? A 15B and a 17B? I wonder which brand they're trying to grab karma from?
Reading about them on some Chinese forums, looks like they made these to directly go against Fluke 15B and 17B.
They're not the only ones, Zoyi also does a 15B+ and 17B+
eg. https://www.aliexpress.com/item/33007708093.html (https://www.aliexpress.com/item/33007708093.html)
Some sellers put "17B+" in all their items just to trap people, eg. https://www.aliexpress.com/item/32844347527.html (https://www.aliexpress.com/item/32844347527.html)
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For sale on ebay:
https://www.ebay.ca/itm/UNI-T-UT15B-PRO-17B-PRO-True-RMS-Digital-Multimeter-Substitute-Fluke-15B-17B/303588597896?hash=item46af4a6088:g:pwMAAOSwhBpe2xUD&var=602818694809 (https://www.ebay.ca/itm/UNI-T-UT15B-PRO-17B-PRO-True-RMS-Digital-Multimeter-Substitute-Fluke-15B-17B/303588597896?hash=item46af4a6088:g:pwMAAOSwhBpe2xUD&var=602818694809)
"Substitute Fluke 15B+/17B+" :-+
My rule of thumb is: Never buy a multimeter with "Pro" in the name.
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Really? A 15B and a 17B? I wonder which brand they're trying to grab karma from?
Reading about them on some Chinese forums, looks like they made these to directly go against Fluke 15B and 17B.
They're not the only ones, Zoyi also does a 15B+ and 17B+
eg. https://www.aliexpress.com/item/33007708093.html (https://www.aliexpress.com/item/33007708093.html)
Some sellers put "17B+" in all their items just to trap people, eg. https://www.aliexpress.com/item/32844347527.html (https://www.aliexpress.com/item/32844347527.html)
These meters are aiming at tricking people though, they are crappy cheapies that wanna use these labels to trick people. Those new Uni-T meters seem to be of a lot higher quality.
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These meters are aiming at tricking people though, they are crappy cheapies that wanna use these labels to trick people. Those new Uni-T meters seem to be of a lot higher quality.
You'd hope so for $95.
"rotation switch is guaranteed to still smoothly operate after 30,000 cycles"
LOL! Somebody's been reading EEVBLOG.
(A real Fluke will laugh at that though)
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The meter seems quite decently built and the air gap around the shunt looks alright - at a typical 3kV/mm for dry air, it doesn't really looks there is a problem. Obviously I don't have one and can't be absolutely certain.
The thing I don't see though, is independent safety certification. I'm curious if all the claims are true.
If your life depends on it being true then don't trust it. Get something with a genuine certification. :-//
The lack of independent verification (which UT139 has) is surely a turnoff, but it doesn't tell the whole story. Reputable brands such as Yokogawa, Sanwa and Hioki do in-house certification but they have a good reputation and track record of pushing out decent gear (a bit less on Yokogawa, but still). Uni-T has goofed up so many times in the past that they have a very long road ahead to boast any quality claims for in-house testing. There's also that pesky loophole the cert agency will only test whatever you ask them to, and that could easily be circumvented (among other potential loopholes)
"rotation switch is guaranteed to still smoothly operate after 30,000 cycles"
LOL! Somebody's been reading EEVBLOG.
(A real Fluke will laugh at that though)
That or joeqsmith's videos. :-+
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These meters are aiming at tricking people though, they are crappy cheapies that wanna use these labels to trick people. Those new Uni-T meters seem to be of a lot higher quality.
You'd hope so for $95.
(A real Fluke will laugh at that though)
Well at least it's similarly priced as the 15B and 17B. I've actually ordered it just to check it out. If I end up wasting 90 bucks, so be it :)
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These meters are aiming at tricking people though, they are crappy cheapies that wanna use these labels to trick people. Those new Uni-T meters seem to be of a lot higher quality.
You'd hope so for $95.
(A real Fluke will laugh at that though)
Well at least it's similarly priced as the 15B and 17B. I've actually ordered it just to check it out. If I end up wasting 90 bucks, so be it :)
I don't know about the 15B or 17B, but the quality of the 101 for me was very flaky. The first (2017 date code) had issues with the display. The second (2016 date code) did not, but both had oxidized pads on the PCB vias and pads, including the ones leading to the LCD.
This may be due to improper storage, but it was coming from two different sellers from very different locations.
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These meters are aiming at tricking people though, they are crappy cheapies that wanna use these labels to trick people. Those new Uni-T meters seem to be of a lot higher quality.
You'd hope so for $95.
(A real Fluke will laugh at that though)
Well at least it's similarly priced as the 15B and 17B. I've actually ordered it just to check it out. If I end up wasting 90 bucks, so be it :)
I don't know about the 15B or 17B, but the quality of the 101 for me was very flaky. The first (2017 date code) had issues with the display. The second (2016 date code) did not, but both had oxidized pads on the PCB vias and pads, including the ones leading to the LCD.
This may be due to improper storage, but it was coming from two different sellers from very different locations.
My 101 was acquired a couple of years ago. It's been sitting in my potable toolbox and gotten pushed around in a sea of pliers, screwdrivers and other crap. Other than scratched screen, it's given me no trouble. I haven't opened up the little thing though.
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The lack of independent verification (which UT139 has) is surely a turnoff, but it doesn't tell the whole story. Reputable brands such as Yokogawa, Sanwa and Hioki do in-house certification but they have a good reputation and track record of pushing out decent gear (a bit less on Yokogawa, but still). Uni-T has goofed up so many times in the past that they have a very long road ahead to boast any quality claims for in-house testing. There's also that pesky loophole the cert agency will only test whatever you ask them to, and that could easily be circumvented (among other potential loopholes)
Yes, Uni-T have the reputation of being "hit and miss", at least to those who follow the industry. Those in the know are going to buy a Fluke or Brymen or one of the Japanese brands in those instances if it's guaranteed safety and design and build quality you are after.
Many people don't know nor care though, they just look at price and some marketing blurb on an ebay listing.
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I have some Uni-T meters. The cheap ones serve the cheap use. Keep them away from things that need safety. The UT139C and the UT17X series are the only I have that I would recommend for general around the house electrical work. Everything else Uni-T that I have seen should be kept to batteries and CATI use unless proven to be safe otherwise. Having said that the clamp meters should be safe for any clamp use but be wary of using the probes over CATII.
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A video review of the UNI-T 15B PRO:
https://youtu.be/a6ZJFw5WoUo
Tear-down begins at around 14:30.