Multimeter for instrumentation

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Mr. Serious said:
On the eevblog forums they have a section for multimeter reviews, and I think they even have a comparison list between many different models. You can read their forums without signing up for an account. The biggest problem with the really cheap meters with unknown brand names is that they don't meet the voltage standards they say they do. Many of the users on that forum say they'll happily use a $10 meter from China, as long as they're only measuring a few volts, but they won't trust it not to blow up when used at a higher voltage that is still within the stated specs on the meter, because the stated specifications are not true, for the very cheapest meters.
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Several bad things about using cheap Chinese meters. Test leads are flimsy and send one of the leads having an intermittent break that could cause serious injury. Years ago I heard at my electrical supply house that a cheap corner cutting electrician was using a cheap Chinese VOM that was only good for 500 Volts AC. He was measuring 480 volts either at night or a weekend when three phase 480 volt service is over 500 volts. Meter blow up in his hand and he went to the hospital for burns and was lucky to only miss a day or two of work. A quality meter will easily last more then ten years.
 
garbo said:
Several bad things about using cheap Chinese meters. Test leads are flimsy and send one of the leads having an intermittent break that could cause serious injury. Years ago I heard at my electrical supply house that a cheap corner cutting electrician was using a cheap Chinese VOM that was only good for 500 Volts AC. He was measuring 480 volts either at night or a weekend when three phase 480 volt service is over 500 volts. Meter blow up in his hand and he went to the hospital for burns and was lucky to only miss a day or two of work. A quality meter will easily last more then ten years.
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I call BS on this claim. There is no way that a meter rated for 500 VAC "blows up" because the voltage was a few volts over. Maybe if it was 1000 V, but few meters would survive that kin of stress. I suspect some kind of operator error.

That does not mean it is a good idea to use cheap junk, but there is a difference between cheap junk that is dangerous to use, and inexpensive stuff that works safely and acceptably for what it is being used for.
 
The main thing about using a sketchy meter is not being able to depend on the data you get.
 
tthh said:
The main thing about using a sketchy meter is not being able to depend on the data you get.
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what data do you think needs to be perfect? it is nice to claim you have a meter that is accurate to +/- 0.05% or whatever, but in practice the vast majority of measurements +/- 10% is adequate.
 
petersonra said:
what data do you think needs to be perfect? it is nice to claim you have a meter that is accurate to +/- 0.05% or whatever, but in practice the vast majority of measurements +/- 10% is adequate.
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Yes, many times close-enough is fine. But, it isn't just the precision. Also, something that's sketchy in one function is more likely to be sketchy in other ways.

I also buy a HF tools once in awhile. But, not for something I'm going to use more than a few times.
 
petersonra said:
I call BS on this claim. There is no way that a meter rated for 500 VAC "blows up" because the voltage was a few volts over. Maybe if it was 1000 V, but few meters would survive that kin of stress. I suspect some kind of operator error.

That does not mean it is a good idea to use cheap junk, but there is a difference between cheap junk that is dangerous to use, and inexpensive stuff that works safely and acceptably for what it is being used for.
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You are usually a pretty sharp guy. I can't cite the date as it was at least 10 years ago, but E C and M magazine has a recurring article called Forensic something or other. This case was a Fire Marshall, an electrician and a Mall Manager, checking voltage on a large piece of switchgear. it blew up killing one and injuring two others. The cause was determined to be that the soldered points on the circuit board were too close together and not per the listing requirements for the rated voltage of the meter. Made in China. It is one of the few of those articles that has always stuck with me.
 
Made in China doesn't automatically mean it is sketchy. Lot's of stuff is high quality and made in china. It has to do with who designed it, what parts are being sourced, the quality control, assembly, etc. Most all Apple stuff is made in china and it's high quality. What is to be avoided is stuff that doesn't use quality engineering, parts, assembly, QC. Now, sometimes that's hard to tell. Certainly there are off-brands that are probably just fine and cost a lot less. It's hard to tell that without knowing more.
 
Strathead said:
You are usually a pretty sharp guy. I can't cite the date as it was at least 10 years ago, but E C and M magazine has a recurring article called Forensic something or other. This case was a Fire Marshall, an electrician and a Mall Manager, checking voltage on a large piece of switchgear. it blew up killing one and injuring two others. The cause was determined to be that the soldered points on the circuit board were too close together and not per the listing requirements for the rated voltage of the meter. Made in China. It is one of the few of those articles that has always stuck with me.
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If that was the case why didn't it blow up the other times it was used to measure 480 V?
 
petersonra said:
I call BS on this claim. There is no way that a meter rated for 500 VAC "blows up" because the voltage was a few volts over. Maybe if it was 1000 V, but few meters would survive that kin of stress. I suspect some kind of operator error.

That does not mean it is a good idea to use cheap junk, but there is a difference between cheap junk that is dangerous to use, and inexpensive stuff that works safely and acceptably for what it is being used for.
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Well if you have it set for ohms and connect it to ~500 volts and it has no CAT rating???
 
garbo said:
Several bad things about using cheap Chinese meters. Test leads are flimsy and send one of the leads having an intermittent break that could cause serious injury. Years ago I heard at my electrical supply house that a cheap corner cutting electrician was using a cheap Chinese VOM that was only good for 500 Volts AC. He was measuring 480 volts either at night or a weekend when three phase 480 volt service is over 500 volts. Meter blow up in his hand and he went to the hospital for burns and was lucky to only miss a day or two of work. A quality meter will easily last more then ten years.
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I think OP is mostly interested in testing signaling such as 4-20mA, 0-10V, RTD's etc. that all use limited energy sources so the personal safety issues not the same as when testing class 1 signal or power circuits.
 
Strathead said:
You are usually a pretty sharp guy. I can't cite the date as it was at least 10 years ago, but E C and M magazine has a recurring article called Forensic something or other. This case was a Fire Marshall, an electrician and a Mall Manager, checking voltage on a large piece of switchgear. it blew up killing one and injuring two others. The cause was determined to be that the soldered points on the circuit board were too close together and not per the listing requirements for the rated voltage of the meter. Made in China. It is one of the few of those articles that has always stuck with me.
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I’ve heard that one too. Another one was a rotation meter, don’t know what brand, or where it was made, but it exploded, they use that case in a lot safety videos, I think they call it “Donnie’s accident” or something like that, but said they never figured out why it exploded. I’m pretty sure I know why, I have one similar to it, and noticed something rattling in it one day. Took it apart, one of the circuit board screws had vibrated loose. Most likely his done the same, and contacted the circuit board solder traces.
 
[OP here]
Part of my problem is that I have to cover a lot of roles--from basic commercial and residential to industrial machines, automation, VFDs, etc. I've had a Fluke T5-1000 fork meter for years which covers most daily basics. The Ideal clamp meter I have started malfunctioning. I wanted the most features I could get with as few meters and dollars I could manage.
I ended up with a bit of balance between trustworthy and cheap.
I got a Fluke 117:
1693329720521.jpeg
www.fluke.com

Fluke 117 Multimeter For Electricians

Check out the Fluke 117 digital multimeter for efficiency in low light. The ideal multimeter to prevent false readings caused by ghost voltage. Buy Now!
www.fluke.com www.fluke.com

And a Triplett CM650:
1693329820431.jpeg
www.triplett.com

600A True RMS AC/DC Clamp Meter (CM650)

The Triplett Model CM650 True RMS Clampmeter can measure AC and DC current up to 600A without breaking the circuit by clamping around a single conductor. This saves time and the circuit will not be damaged. Read More > DESCRIPTION The Triplett Model CM650 True RMS Clampmeter can measure...
www.triplett.com www.triplett.com

I haven't really put them through their paces yet--just some basic test measurements. The Triplett LCD display isn't the best, and it did read lower amps than my Fluke fork meter when testing with a heat gun. The Fluke is nice, but the non-contact tester is rather ridiculous. There is a Hi and Lo sensitivity, but even on low, it alerts when pointed at just about anything: like a wooden shelf with no power nearby!
 
My Fluke 23 was fabulous (and fast reading) up until the day it got stolen. My Fluke 77 lasted decades before biting the dust. My ExTec and it's brand labeled twin from Lowes (south wire) both worked well for a while, then got strange and unreliable. The cheap clamp meters from Harbor Freight only read AC, not DC & the resolution is poor. The really cheap red meters from Harbor Freight actually are pretty accurate on the volts scale and last better than I expected, but they don't have a clamp. My Tectronix scope died inside a padded case in transit from NYC to CA after about 3 years of use. My analog meters all still work. The old Simpson is my favorite. A fluke clamp attachment plugged into an o-scope is a real handy thing.
 
JimInPB said:
My Fluke 23 was fabulous (and fast reading) up until the day it got stolen. My Fluke 77 lasted decades before biting the dust. My ExTec and it's brand labeled twin from Lowes (south wire) both worked well for a while, then got strange and unreliable. The cheap clamp meters from Harbor Freight only read AC, not DC & the resolution is poor. The really cheap red meters from Harbor Freight actually are pretty accurate on the volts scale and last better than I expected, but they don't have a clamp. My Tectronix scope died inside a padded case in transit from NYC to CA after about 3 years of use. My analog meters all still work. The old Simpson is my favorite. A fluke clamp attachment plugged into an o-scope is a real handy thing.
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Cut my teeth on my dad's Simpson model 260 back in the late 1960's. Were great meters. Analog modern meters with their auto ranging and not having to worry about pegging a meter pointer when you have the leads reversing while reading DC voltages. Still have my dad's 600 amp GE clamp on amp meter.
 
I still use my Simpson 260 a few times a year for in-circuit MOSFET tests in a 40 year old radio transmitter.

My go-to meter is a 30-year-old Fluke 77. We also have an ancient Amprobe clamp-on and a Milwaukee clamp-on.
 
Strathead said:
Since when is patriotism part of politics?
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You would be suprised.
I spent my whole life serving this great country in many ways and always love hearing playing and respecting the nat. anthem.
3 months ago a good friend and competitor of mine asked me to pit for him as he had 3 back to back races and needed the 3 bikes ready at pit out after each race. This includes making sure my rider knows his grid spot and race orders and time..
I showed up right as the riders meeting was finishing so i got to writing down all the info as the anthem was playing- lots of work to do that morning.
First time i didnt take off my lid and a dude came up to me yelling at me and i told him i have a job to do but he wasnt having it.
Per what he was yelling, he made it political- and racist....
The one time folks.
 
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