EEVblog #1067 - Analog vs Digital Multimeters

[oldway]

I have plenty of experience in the field I used to install service and later manufacture generating plant. I learnt one important thing when I first started from my employer, if any one but any one comes and says hurry up, tell them that they have the choice of the job takes as long as required to do it safely or they can have the plant shut down for three months while the health and safety investigate what went wrong. I have worked on generators for the likes Of Ciba Gigy and Dows and at no time did I get the hurry up.

OK, everything is explained .... you have never worked in maintenance and industrial and power electronic repair ..... In installation, it's totally different, you work at ease, you stop to have tea or coffee when you want, you disconnect what you want when you want .... the life of pasha!

In maintenance and repair, it's something else .... try to unplug anything in an oil refinery, try to stop to take your tea when a factory like Pirelli is stopped waiting for you to repair the 5000A dc drive that feeds the plant's main rubber mixer, try to make BASF, DEGUSSA, FINA or others to wait for you to fix "without to get the hurry up" and without safety their faulty equipment....

Already, and to begin with, in these factories you must not only have taken safety courses and be qualified, but in addition, you must pass a theoretical exam about safety rules and regulations before being allowed to enter the factory ... I can guarantee you that with all the bullshit you wrote on this forum about safety, you'd be banned for life from these companies.

[oldway]

Accident with a multimeter ....

It's so sad that I hesitated a lot to post this video ......

Some lose their lives for nothing ....

Let's try to prevent such an accident from happening again,

Respect the safety rules .... This video explains my determination to defend this principle.

[G7PSK]

That indecent was not the fault of an analogue meter. The meter in question he was using looked like a Fluke DMM. The switch gear either did not have automatic lock out or that had been disabled.
The argument here is not about safety at work with HT systems but as to the safety of analogue meters when used in the correct environment and the correct way. I used analogue entirely until around 2006 by which time digital were robust  and cheap enough for me to go over to them in the main. I personally never worked on anything above 1100 volts as that was the voltage of the largest gen sets I ever worked with. I now only service a few smaller sets the largest of which is 150 KVA 415 volt.

I can assure you that safety while working is my priority to the point that I have walked off jobs in the past as the site or other workers were not safe to be around, better no pay than dead. 

[oldway]

That indecent was not the fault of an analogue meter. The meter in question he was using looked like a Fluke DMM. The switch gear either did not have automatic lock out or that had been disabled.
The argument here is not about safety at work with HT systems but as to the safety of analogue meters when used in the correct environment and the correct way. I used analogue entirely until around 2006 by which time digital were robust  and cheap enough for me to go over to them in the main. I personally never worked on anything above 1100 volts as that was the voltage of the largest gen sets I ever worked with. I now only service a few smaller sets the largest of which is 150 KVA 415 volt.

I can assure you that safety while working is my priority to the point that I have walked off jobs in the past as the site or other workers were not safe to be around, better no pay than dead.

Where did I wrote that this accident has been the fault of an analog multimeter ?

Do you have Alzheimer's or are you just stupid?

You should consult a doctor, because it is 5 pages that you repeat the same thing.

All this because on page 1 I had the misfortune to write "never use an analog multimeter on high energy circuit."

You are just ridiculous, your posts are pure spam ....You even said stupid things about the Bible.....

Well your attitude makes me think of people who think the bible is absolutely true and not a total work of fiction with a few life codes thrown in.

[tzok]

All this because on page 1 I had the misfortune to write "never use an analog multimeter on high energy circuit."

You have not only write it once but you are repeating this over and over again, rejecting the facts, that safety of a meter has nothing to do whether it is analog or digital. Most modern cheap DMMs are equally or even more unsafe when used on high energy circuits than major brands analog meters from '80s, and '90s. Why don't you accept that fact? You should always use adequate equipment to the task you are doing. And you should never think that "safe" equipment will save you from making fatal mistakes. People who are working with HEC are supposed to know what they are doing, average person has no access to such circuits. If he had access, after reading your post, what would he choose? Having a choice between, lets say, Metrix MX1, and Aneneg AN8008? Which of these two do you think is safer? According tho the markings they are both CAT III 600V, and you said he must not use analog meters... supposedly he should not touch this circuit at all, but if he had no other choice?

P.S.
If safety is not an option - then why people still ride motorbikes instead of much safer cars?

[floobydust]

Any multimeter can be unsafe if used incorrectly- analog or digital.

That arc-flash video determined he was measuring phase-phase voltage in a 2.3kV MCC with a Fluke handheld multimeter, along with seven additional mistakes that cost him his dear life.


Almost all analog multimeters are from an era before safety standards. It doesn't mean they are unsafe by nature, they are such a big multimeter with plenty of room for spacings, big fuses- compared to small DMM's.

The Simpson 260 analog VOM has undergone many revisions over the decades, and there is the safety version Model 260-9S.

Cheap chinese multimeters with fake IEC 61010 approvals are garbage and much less safe than old bakelite.

[hamster_nz]

Do you have Alzheimer's or are you just stupid?

So somebody (G7PSK) has avoided working on live gear because he is skilled and take a cautious approach to such things, and has had a long career which involved sometimes using an analog meter without blowing himself up. The systems were designed such that they can be safely powered down for maintenance.

Somebody else (Oldway) is working in a different area has had to work on live gear because production cannot be interrupted, and would like everybody to only use a top of the line DMM because of the additional engineered-in safety features.

The way I see it, G7PSK is actually the safer guy - having greater control over risks, allows greater working safety margins day to day. Should a meter blows up, it seems nobody will be the worse for it because the risks have been managed.

"Oldway" seems to have a whole lot of risks he can't directly mitigate, they are relying on processes, procedure and their equipment to keep them safe. A single failure or stuff-up could be very bad.

If one of you was to come to serious harm due to a bad day at the office, my money is on it being Oldway. G7PSK's environment allows for greater overall safety, but "Oldway" seems to constantly be one slip-up from disaster.

Does that about sum it up?

Last time I looked this was an Electronics forum, and servicing HV lines, multi-megawatt generators or industrial induction furnaces is only a curiosity to most...

[SilverSolder]

Last time I looked this was an Electronics forum, and servicing HV lines, multi-megawatt generators or industrial induction furnaces is only a curiosity to most...

Well, if you want to make a headphone amplifier that can really be considered serious...

[Brumby]

As far as I am concerned, electrical power systems are a valid component of the general interest that is expressed on the EEVblog.

As for the whole analogue versus digital metering issue, we seem to have gone WAAAYYYY past ANY reasonable boundaries defined by these differing technologies and well into a head-butting contest on safety in high energy environments on the industrial scale.


The relevance to the topic of this thread has evaporated like a shorted 10kV busbar at a power station.

[xani]

Almost all analog multimeters are from an era before safety standards. It doesn't mean they are unsafe by nature, they are such a big multimeter with plenty of room for spacings, big fuses- compared to small DMM's.

The Simpson 260 analog VOM has undergone many revisions over the decades, and there is the safety version Model 260-9S.

What baffles me is why they didn't just certified (and made neccesary changes, as they obviously know what would need to be fixed) their base model, just sell +$80 "safety tax" one.

Cheap chinese multimeters with fake IEC 61010 approvals are garbage and much less safe than old bakelite.

Sure but I doubt anybody is seriously comparing +$300 Simpson to $10 chinese DMM.

[Fungus]

Here's a more modern analog meter. CAT III, 600V. It even has a neck strap so you can hang it close to your vital organs:

[Fungus]

That arc-flash video determined he was measuring phase-phase voltage in a 2.3kV MCC

True, but many (most?) arc-flash incidents occur at much less than that.

The Gossen multimeter manual says:

Voltage measurement
...
The multimeter may only be operated by persons who are capable of recognizing contact hazards and taking the appropriate safety precautions. Contact hazards exist anywhere where voltages of greater than 33 V RMS may occur.

If 33V sounds silly to you then stay away from "high energy" electricity.

Arc flash FAQ

[bd139]

For those who haven't seen it or worn it, proper arc flash protection looks like this:



One of the lesser known risks is the sudden UV burst which burns your retinas out instantly, even if you're not actually affected by the burning hot metal spraying all over you.

[Fungus]

For those who haven't seen it or worn it, proper arc flash protection looks like this:

Have you worn that? Cool! 

From the FAQ:

Does Proper PPE Protect me from Injury?
Protective equipment is designed to limit burns to second degree burns.

An arc blast can knock people off of elevated platforms or blow doors or shrapnel across the room, to which the proper arc flash PPE provides little to no protection

One of the lesser known risks is the sudden UV burst which burns your retinas out instantly, even if you're not actually affected by the burning hot metal spraying all over you.

From the FAQ:

The arc blast will likely vaporize all solid copper conductors, which will expand up to 67,000 times their original volume

...
concussions, collapsed lungs, hearing loss, shrapnel injuries, and broken bones are the common injuries.

 

[bd139]

Yes they made us wear one before we specialised our degrees. It put me off power electronics. So I picked microelectronics and ended up wearing a clean room suit which was just itchy as fuck instead.

[Fungus]

The fun part is how many people are using this image to advertise their electrical safety courses.



But anyway, back to analog vs. digital... digital is best, dammit!

[bd139]

FFS that's just the worst image ever. Then again the electricians I have seen over the years, the dude above is over-equipped. One I know doesn't even have a working DMM. Drill a hole in the wall? Cut the breakers first, because he got a shock once 

This is a better one

[Fungus]

Remember: Trust your nose. Stay away from any cabinets that fail the sniff test!

[bd139]

Ouch!

That's actually a good methodology. Good smells to learn the difference between:

1. Ozone. Something is ionizing or arcing. High voltages in there.
2. Hot fibreglass. Something is about to be trouble.
3. Air feels or tastes buzzy. RF about.
4. Burning carbon. Something is shorting or overloaded.
5. PVC. Someone should have used teflon wire or a large problem is about to occur.
6. Burning enamel. Transformer fucked. Isolate quickly before the only breathable air is the foot closest to the ground.
7. Burning metal. All the PVC and enamel is gone. Duck and run.

[G7PSK]

For those who haven't seen it or worn it, proper arc flash protection looks like this:



One of the lesser known risks is the sudden UV burst which burns your retinas out instantly, even if you're not actually affected by the burning hot metal spraying all over you.

Wonder how effective those outfits are. I used to have a plasma cutter rated at 300 volts Dc 55 amps output, that would spray out an plasma nine inches long  and cut through anything including bricks ( I tried it) a copper plasma is used as anti tank weapon, so I wonder if the copper bus bar turned into a plasma and came in the direction of that suits wearer what protection id would afford, and before any one jumps down my throat I am sure it is better than nothing.

[oldway]

Always balance the pros and cons and do not exaggerate ....

I remember that in a chemical industry, I had been forced by the factory safety regulations to use:

- safety glasses (which I always used)

- helmet with face shield

- thick insulating gloves

- I wore also my cotton overalls (cotton does not catch fire easily)  and safety shoes (which I always used)

And all this to make some simple measurements of voltage on a bank of batteries of fifty ah and total voltage of about 120V

We fall into the excess because:

1) with safety glasses + face shield, vision is very small

2) the insulating gloves were very thick and did not allow to hold the probes correctly, nor to make gestures of precision.

So, over-protection may increase the risks of accidents, which is a mistake.

It must also be remembered that disconnecting a switch or a circuit breaker is not enough to make sure that the equipment is powered off.

Visible power interruption, grounding and locking (padlock) to prevent reconnection by mistake are the correct safety procedures

[bd139]

Wonder how effective those outfits are. I used to have a plasma cutter rated at 300 volts Dc 55 amps output, that would spray out an plasma nine inches long  and cut through anything including bricks ( I tried it) a copper plasma is used as anti tank weapon, so I wonder if the copper bus bar turned into a plasma and came in the direction of that suits wearer what protection id would afford, and before any one jumps down my throat I am sure it is better than nothing.

Watch for yourself. They're pretty good. An arc flash doesn't last long, at max a few cycles before something goes ping and it clears so this isn't designed to cope with persistent energy output, but a sudden impulse of energy and impacts. A plasma cutter would work through it in no time.

[G7PSK]

When checking leads acid batteries a face shield is not over kill, I have seen several batteries explode from over gassing and just a small spark, I have had that happen to me with a car battery when I was around fourteen and disconnected a charger incorrectly, I was lucky the acid only went on my hands and clothes, I washed it off straight away but when my mother took my clothes out of the washer she wondered why they were full of holes.

[bd139]

Yes they are nasty things. SLA batteries don't take long to become LA batteries 

[oldway]

When checking leads acid batteries a face shield is not over kill, I have seen several batteries explode from over gassing and just a small spark, I have had that happen to me with a car battery when I was around fourteen and disconnected a charger incorrectly, I was lucky the acid only went on my hands and clothes, I washed it off straight away but when my mother took my clothes out of the washer she wondered why they were full of holes.

I also have seen industrial lead batteries explode, and when I have to work with such batteries, the first thing I do, before any other, is to look if there is shower of toilets not far....
When there is an explosion of a lead battery, the first thing you need is water, a lot of water.....

In the case of this chemical industries, they where vrla batteries....I never seen something bad with this kind of batteries even I was working with maintenance and repair of high power UPS (10 to 400Kva's)