Author Topic: Multimeters that do not appear to meet their safety specs. (updated frequently)  (Read 404871 times)

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Offline KD2FVM

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I thought the safety rating of the meter and leads (600V for example) meant that the user would be safe connected to (and protected from) voltages that high, not that the meter could measure that level. That said, a 250V fuse would be appropriate if the meters range was 250V and less. The fuse is to protect the meter, safety rating or class rating is an insulation safety rating and measure of dielectric strength.
 

Online AVGresponding

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The fuse rating of 250V is a bit odd, when you find it in meters supposedly safe for measuring at higher voltages.

The fuse of course only sees a much smaller voltage, in normal conditions. However, in the event of the fuse blowing due to overcurrent, both the voltage rating and the breaking capacity come into play.
Essentially, the fuse only meets its breaking capacity if it's operating within its voltage range. Use it outside that range and you're going to get reduced protection.
In reality you're only going to see voltages larger than that if you make a mistake measuring current in a mains voltage circuit or similar.
I wouldn't trust or use a meter that has this type of fuse for this measurement.
nuqDaq yuch Dapol?
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Online joeqsmith

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Some videos on multimeter safety.     





How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
Software, documentation and test reports for the low cost NanoVNA & V2 Plus 4 may be found here:
https://github.com/joeqsmith
 
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Online joeqsmith

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Looks like he has a new video on safety. 


How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
Software, documentation and test reports for the low cost NanoVNA & V2 Plus 4 may be found here:
https://github.com/joeqsmith
 

Offline rsjsouza

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Funny the issue with the decimal point on the Amazon meter. I just received my Fluke 101 that is missing both resistance multiplier indicators (M and k). I am working to convince the seller this is actually a defect.
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline exit_failure

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Looks like he has a new video on safety. 



I think that what he says in his video is wrong or at least dangerously incomplete: Having a device tested by a certified testing house is fine and dandy but what's really important is what norms and standards it has been tested against. UL or any other similar testing institution will only do the test you ask them to do. So being UL listed may for example only mean that they tested it for environmental or fire safety or but not electrical safety and then the CAT rating may just as much be a lie as for any 5 dollar meter from aliexpress.
That means that the really important step is not finding the meter in some database but looking at the tests they actually performed.

edit: spelling and last sentence
« Last Edit: June 23, 2020, 10:31:05 am by exit_failure »
 

Offline Lightages

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What one needs to keep in mind when thinking about multimeter safety is if it has a rating is that it actually has a testing house proof of its safety. CE is useless IMHO. Anyone can place CE on their product and all they are doing is hanging themselves out for liability should it actually not pass the CE directives.Some countries don't care or worry about the liability so it is a useless certification. If a product has a TUV, UL, CSA, or some other certification then the records of what criteria has been tested are available for the asking. This thread was started to help people understand the differences between safe (or safer) meters and pure BS. I am glad that has raised some awareness.

Oh yes..... I am back!
 

Offline tautech

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Oh yes..... I am back!
And nearly 2 years since you posted last.  :o

Settled back in the GWN ?
Avid Rabid Hobbyist
 

Offline Lightages

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GWN, Great White North? I am worried about that phrase right now.....

I was getting bored with my new 9-5 life so I decided to get active again. There will be videos!
 

Offline rsjsouza

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Welcome back, Lightages! You were missed.
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline Lightages

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Thanks. I missed my interactions here too.
 
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Offline dylanmitchell

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What companies always meet or exceed listed specs? Fluke, Agilent/ Keysight? Others?

Didn't see Fluke on the list but Amprobe was on there.
Fluke 117, 323, T+ Pro, Amprobe AMP-320
U.S. 120/240 VAC 60H
 

Offline Lightages

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If I were to try to name the companies that always meet listed specs, it would be a very short list. I would say, with reservation, that you could basically pick up an new meter from Fluke, Keysight, Brymen, Amprobe, Hioki, Yokogawa, and be sure you have a meter that actually is as "safe" as it claims. That is not to say that Flir, or others would be equally as good just that I don't have enough experience with them to say anything useful.

The point of this thread is not to say that the meters listed are unsafe in any circumstance. The point is to point out the flaws. Safety is not just about the meter. The idiot holding the meter has more to do with safety than does the meter. But if you trust a meter to do what it says and it can't and the specs are a lie then you need to know so you can adjust your behavior to be safer.
 

Offline ElektroHS

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If I were to try to name the companies that always meet listed specs, it would be a very short list. I would say, with reservation, that you could basically pick up an new meter from Fluke, Keysight, Brymen, Amprobe, Hioki, Yokogawa, and be sure you have a meter that actually is as "safe" as it claims. That is not to say that Flir, or others would be equally as good just that I don't have enough experience with them to say anything useful.

The point of this thread is not to say that the meters listed are unsafe in any circumstance. The point is to point out the flaws. Safety is not just about the meter. The idiot holding the meter has more to do with safety than does the meter. But if you trust a meter to do what it says and it can't and the specs are a lie then you need to know so you can adjust your behavior to be safer.

you are right... any electrical device is "dangerous" in case of incorrect usage. Therefore "end-user" should follow all rules to be safe... otherwise the result of incorrect usage even certified meters can be ended not so good.
 


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