Freaky Amazing DMM?!

Most analog meters are pretty high impedance as well. On the order of nearly 10M Ohms per volt.

My first Heathkit meter was.

Well then take your stupid ass somewhere else, 'this idiot'.

We don't need your kind around here, 'this idiot'.

That is a very good moniker for you though, 'this idiot'. You should stick with it.

On what planet??

Almost all analog meters on the market are in the oder of 10's of Kohms / Volt. My Triplett 630, a very typically rated industry standard analog meter for example is 10-20K/V on DC and 5-10K/V on AC volts. The most sensitive analog meter I've ever owned (and from memory, saw) was rated at 100Kohms/V.

Those that are higher are FET input meters and they are NOT rated in ohms/volts, as the impedance is no longer based on the meter movement. My Tandy FET analog meter is 10Mohms fixed on DC volts, and non-FET input on AC, rated once again in 10's of K per volt.

You might need to go back to basics:

Dave.

This one. Yamato Y3 2Kohm/V ac & dc. Bought around 1963. Still works perfectly. :) Also it survived 2 digital meters.

Best regards, Spehro Pefhany

Nice reply except for this bit of baby bullshit.

You might need to f*ck off and die.

No FET front end on that!

Bwuahahahahah!

I had one too.

An indirectly heated cathode Field Effect Tube.

Only if you don't know how to interpret the better meter. Its a dumbed down toy for wire pullers. I've seen too many over the years that couldn't find an open neutral, or bad connection unless it was on fire.

If you are reading 83 volts, either it is a phantom voltage, or you have a 40 volt drop in a 120 volt circuit, or 160 volt drop in a 240 volt circuit, which is damn unlikely. If you can't see this, you don't know what you're doing.

The appropriate tools start with a well trained brain. Otherwise, you are a monkey throwing crap at the problem.

If is working with what you described, it certainly won't be 'low impedance', because the the current flow required, times the voltage being read would be so high that the meter would need to be in a 55 gallon drum of transformer oil, and able to dissipater several kilowatts. All this would weigh several hundred pounds.

My experience is a broadcast engineer, (The largest was at a 5 MW UHF TV site.) industrial electrical work, and specialized electronics that you'll never see, without going to the International Space Station.

So, you don't use current transformers or clamp on AC ammeters?

If you are working in dangerous locations without the proper training you are likely to die. If you are properly trained, the company supplies the proper equipment needed to do the work. If you work for some fly by night schlock outfit without proper training an safety equipment OSHA won't collect a cent, because the owners will flee the scene before they arrive, and have nothing worth seizing, anyway. the last time I heard of someone working with HV dying, it was a nine bucket that was working in Florida to help restore service after hurricanes, when some idiot hit it when the crew was on its way home, and cause it to roll off I-75 in North Florida.

You weren't discussing, you are posting old wive's tales. Power generation has nothing to do with portable meters. Current transformers and voltmeters are permanently installed at each generator so the can monitor and balance the load on each alternator.

So it's a vacuum tube front end instead - same thing, same result. A fixed 11Mohm input, not 10M/volt as you foolishly claimed.

Dave.

"Michael A. Terrell" wrote in news:rOWdnQ1TB4W1kOHUnZ2dnUVZ snipped-for-privacy@earthlink.com:

And both extremly impressive too, yet apparently in disagreement.

I don't think that high an experience is needed to understand this anyway, I learned it at 14 when an aging friend of the family taught me how to build my own (and first) multimeter.

Ohm's law.

And a bit of awareness of insulation strength when high volts are involved.

If you're using a low resistance input you might have to take it into account for accurate measurements but on mains, the error is small, so it's worth keeping inputs resistance low for meters dedicated to such systems, for reasons plenty of posts have explained, so I won't flog that horse now.

If you have strong insulation, you can probe an HV circuit without trouble, just make sure you understand what the meter says. If a meter designed to tax the system as lightly as possible says 83V it means 83V, the problem isn't the meter, you just have to know enough to interpret the truth it tell you. (Mike Terrell got this one right). If you also need to know current through the same meter, you could do it by measuring small voltage across a part of one conductor, then measuring resistance of that part after removing power. Most current meters just do this internally anyway, but they 'know' the resistance of their shunts so they calculate correctly anyway.

So the question isn't who is the most experienced, it's who is right? And take care, because if two people with real experience start arguing over something as basic as Ohm's law, they'll do each other's reputation harm, as well as making it hard for newcomers to trust what they read here.

!0 M Ohms will not load the circuit under discussion enough to clamp local noise either.

te:

ble.

It should be clear the discussion is about high available fault current - the current you get when the source is short circuited. This is a really basic concept in design and protection of high current AC power circuits. (But it may not be something you have run across.)

High available fault current can result in arc flash. Arc flash can result in major injury and death in addition to major equipment destruction. Arc-flash is estimated to kill 200-300 people a year. OSHA has made arc-flash an issue. Safety protection may require wearing an arc-flash suit.

One of the smartest electricians I know was seriously injured by arc flash. And it was through an equipment failure - he made no mistake.

The issue I raised is appropriate meters. As I wrote above, the IEC has measurement Categories I-IV. If working in high energy locations, like panel boards and services, the appropriate meters are Cat III and IV. These meters are designed for the riskier environment and have better transient withstand and fusing.

My analog Triplett 310 has a glass fuse. I have a Beckman digital that has a similar fuse. They might be safe in Cat I. My Fluke is rated Cat III and IV. That includes transient withstand well above the nominal voltage rating and high interrupt capacity fuses.

OSHA might be real displeased if the wrong meter was used. And when OSHA is unhappy you might be unhappy.

If you didn=92t assume everyone else was an idiot you might actually learn something. (But probably not Archimedes.)

-- bud--

Is it a phantom voltage? Do you have an open neutral? Voltage coming back through another device? One of many other possibilities?

Arloe can eliminate one of them real fast because he knows what he is doing.

How fortunate that Arloe and Stewart and I are well educated and know what we are doing.

If you followed the thread you might understand how =93low impedance=94 is being used.

-- bud--

Which is NOT a problem with ANY modern meter.

In other words, IDIOT... EVEN IF IT FLASHES IT WILL NOT CAUSE A HIGH CURRENT INCIDENT.

Two simple premises, dopey f*ck.

ONE: The meter leads are SMALL gauge! Do you even know what that means?

TWO: WHERE is the short circuit, IDIOT!?

HIGH VOLTAGE arc flash kills 200 to 300 people a year.

Low voltage arc flash, not nearly as many in that statistic.

When you express statistics, you should be careful not to massage them to make your position appear stronger. It will always bite you in the ass.

It is not just about current. I have seen plenty of systems capable of 2000 A and more at 24 V and less and there is no arc flash hazard present. It is much more about transient energy capability and total power available. I have reviewed such calculations once, i will have to do it again. See NFPA 70E which is about how to do the analysis and set up the appropriate protection measures including personal protective equipment and personal protective clothing. For the reason to do the study see 40 CFR 1926.

I doubt that the annual death toll is that high, though it is certainly not zero. I hear of about 1 or 2 a year, there may well be more that i do not hear of.