Freaky Amazing DMM?!

Spurious Response wrote in news: snipped-for-privacy@4ax.com:

You little shit, you just bloated my killfile again.. Just stop digging, that's all. When in a stupid little hole you dug for yourself, stop digging. There's nothing admirable about stupid persistence. With your attitude, if what happened to me happened to you, no doubt you'd be shoving the cable ends in there for half an hour before you got to tired to try any more.

How surprising. You still have no idea what arc flash is.

The thread is about "low voltage" - below 600V (particularly 480V for the US).

The quote above is about "low voltage" as is the source article.

You are still stupid. And do not know the limits of what you know. And not willing to learn.

-- bud---

So does a screwdriver against the case, and to a buss bar, but I won't do it.

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There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.

??????? Don't be stupid.

How NOT surprising that you are still making retarded assessments based on ZERO facts.

You do not know a goddamned thing about what I may or may not be familiar with.

You are a goddamned retard. You should f*ck off and die... Hopefully as the result of a huge copper vapor arc flash. Bwuahahahahaha!

Spattered... spattered... his brain's been splattered, spillin' all over...

Goddamned google groups retards.

Do you means stupid, like a row of question marks is?

I have always hated little gang boy retarded punks in my news groups.

You cannot gauge stupidity from your depths of stupidity, you stupid twit. Yes, you are deep in the barrel.

You really don't get what Bud's talking about.

Arc flash while working in 'low voltage' switchgear (600V or less) can be deadly. And most electricians *do* use a handheld meter working in such switchgear. There is no need for high-voltage probes there. Bud's not talking about high voltage overhead transmission lines.

The very high fault currents available in such load centers can/do cause vaporization of copper. (yes, *vaporization*, where the copper actually changes to the gaseous state). Such load centers may have a feeder that won't trip below 1000 amps or higher. A 'high impedance' fault such as a sustained arc that draws several hundred amps at 600V will not trip the feeder and so it will continue to arc for quite some time. All that power concentrated in the confines of a load control center will vaporize a good deal of the conductor.

Arc flash protection includes specially rated face shields that can absorb the energy of a condensing gas cloud of copper without melting. Ordinary plastic face shields are not allowed in such work as the heat from the plasma gas cloud will just melt them onto your face. Similar precautions are needed for the arc flash suit material worn.

daestrom

I don't want your job. You're the expert at stupid.

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There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you\'re crazy.

Actually it does cause false voltage readings even in circuits with no "loose nuts". You can connect the meter to a point in the circuit that is open somewhere, perhaps because of an open switch contact, and you get false voltage readings that can range from 10V to close to line voltage due to stray pickup of the wires. It causes electricians to sometimes misdiagnose problems, and it causes confusion. I often demonstrate this to my training classes so that they are aware of it.

This is an unavoidable and unfortunate side effect of high impedance digital meters. You need to understand it when you use them so that you can question and investigate readings that don't make sense.

Analog meters don't have this problem, but they are disappearing because the analog circuits can not meet the necessary safety standards.

Ben Miller

--
Benjamin D Miller, PE
www.bmillerengineering.com

You mean that cheap analog VOM had low impedance inputs. There were millions of VTVM and FET input analog meters with a 10 Megaohm input impedance in use over the years, and a lot are still in use.

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There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you\'re crazy.

Of course not. The "loose nut" is the one interpreting the measurements.

Right. The typical sparky is clueless. This fact has been demonstrated here endlessly.

It certainly may be if you're clueless.

"Analog" has nothing to do with it.

Those are great on a lab bench, however very few were ever used for industrial power measurements. FET inputs are not notoriously rugged, although they could be used if desired. It is difficult to run an extension cord for a VTVM out on a factory floor, not to mention the smoke that can escape when you apply a grounded test lead on a power system measurement, assuming that you survive to talk about it :-(

You will not find very many analog meters with an IEC CAT rating, with good reason. The typical analog industrial meters such as the Amprobe RS series or the Simpson 260 series have resistor networks on the inputs, and very likely don't have the requisite creep and clearance distances in their construction. There are also problems with the Ohms circuits. One of the IEC requirements is that you can safely apply maximum rated voltage (ie. 600 or

1000 volts for example) to the meter inputs with the range and mode switches set to any setting. The meter doesn't need to continue working, just fail safely or do nothing. Many meters have fuses for the amp ranges, but analog ohms circuits can fail catastrophically if high voltages are applied to them. The manufacturers just can not justify the redesign of those meters to meet the safety standards.

Ben Miller

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Benjamin D Miller, PE
www.bmillerengineering.com

AND they worked fine for the purpose being discussed and still do.

Bwuahahahahaha! I just love made up statistics.

Your true colors are showing.

I know you are smart, but this bolstering of your OPINION bullshit is just that and nothing more.

No bolstering of anything and no statistics. This is based on personal observation.. I have seen electricians of all ages using many types of meters, from wiggy's to amprobes to Radio Shack digitals to high end Flukes. I have NEVER seen any of them carrying around a VTVM and an extension cord to power it! It is completely wrong for industrial measurements, not to mention unsafe. Explain, for example, how you would measure line-line on a

480 volt three-phase system, with a VTVM that has a grounded probe (yeah, I know, a three-prong adapter and a piece of cardboard to isolate the meter enclosure.)

I won't say the same thing about FET input meters, as there might be some used. I just have not seen any. Since they are battery powered, they at least have isolated leads.

We have electricians on this group. Let's see what they say.

Ben Miller

--
Benjamin D Miller, PE
www.bmillerengineering.com

Some VTVM had a built in battery for portable use. They were rare, but they existed. They used subminiature tubes with a 1.5 or 3 volt filament like those in early hearing aids.

The 260 is a dinosaur, over price instrument in today's work environment. Even if it was modified and certified, it would be sold to a niche market and not worth the engineering costs.

The early FET input analog meters I've used would die if their was a tiny spark when probing. If they had a small choke on the input to filter the RF, they were fine, but it would void the certification.

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There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you\'re crazy.

NOBODY said a goddamned thing about an AC powered device. Other than YOU.

I have seen VTVMs powered by old B+ batteries, as in a 63 Volt source.

Just to depose what I know was going to be your "You don't even know what a VTVM is!" CRAP, before it even starts.

I am not denying that. I am just saying I have never seen an electrician with one.

Hey, give me little credit. We have both been on this group for awhile, and I am aware of your electronics background.

Ben Miller

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Benjamin D Miller, PE
www.bmillerengineering.com