I've got a dead circuit in the garage which worked fine until I plugged in a
new-to-me tool and apparently shorted the power switch to the machine base.
That created a noticeable spark at the tool and instant power loss to that
outlet. Unplugged the tool, popped downstairs to the main electrical panel
and reset a tripped breaker. Back upstairs but still no power to the outlet
or one other nearby.that is apparently on the same circuit. I turned off
all of the circuit breakers that were likely to power the blown circuit and
pulled the duplex recptacle ffrom the wall for inspection. It has two black
wires on the hot side and two gray wires on the neutral side. Ground is
apparently supplied through the conduit. No evidence of arcing or damage to
the receptacle and there was 40 M-ohm resistance across the hot and
neutral terminals. The receptacle was replaced with a new one, just in
case.

All of the circuit breakers were turned on in the panel, but there is still
no power to the outlet - voltage across the hot/neutral terminals is around
1 VAC. I checked all of the breakers again and they are all in the on
position.

I'm perplexed - what might be causing the problem?

Mike

"Mike Henry" wrote in message
...
I've got a dead circuit in the garage which worked fine until I
plugged in a
new-to-me tool and apparently shorted the power switch to the
machine base.
That created a noticeable spark at the tool and instant power loss
to that
outlet. Unplugged the tool, popped downstairs to the main
electrical panel
and reset a tripped breaker. Back upstairs but still no power to
the outlet
or one other nearby.that is apparently on the same circuit. I
turned off
all of the circuit breakers that were likely to power the blown
circuit and
pulled the duplex recptacle ffrom the wall for inspection. It has
two black
wires on the hot side and two gray wires on the neutral side.
Ground is
apparently supplied through the conduit. No evidence of arcing or
damage to
the receptacle and there was 40 M-ohm resistance across the hot
and
neutral terminals. The receptacle was replaced with a new one, just
in
case.

All of the circuit breakers were turned on in the panel, but there
is still
no power to the outlet - voltage across the hot/neutral terminals is
around
1 VAC. I checked all of the breakers again and they are all in the
on
position.

I'm perplexed - what might be causing the problem?

Mike

You sure there isn't a GFCI upstream of the outlet?

In article ,
says...

All of the circuit breakers were turned on in the panel, but there is still
no power to the outlet - voltage across the hot/neutral terminals is around
1 VAC. I checked all of the breakers again and they are all in the on
position.



First thing is to check for voltage right at the screw
terminal on the breaker. Maybe the short damaged the
breaker?

Ned Simmons

There are also some breakers which require the handle to be pushed further
"OFF", then "ON" to reset after tripping. Just flipping this type to "ON"
will not reset it.
Don Young

"Ned Simmons" wrote in message
...
In article ,
says...

All of the circuit breakers were turned on in the panel, but there is
still
no power to the outlet - voltage across the hot/neutral terminals is
around
1 VAC. I checked all of the breakers again and they are all in the on
position.



First thing is to check for voltage right at the screw
terminal on the breaker. Maybe the short damaged the
breaker?

Ned Simmons

And do you know where the wiring from the breaker goes before it gets
to the outlet? Some do-it-yourself electrician may have left a loose
wire nut somewhere.

Dennis in nca

and, just because the breaker lever says "ON" doesn't mean that it is in
fact ON - I'd start by being sure that there is voltage coming out of the
breaker - if yes, then you can follow the circuit and see where it goes away
"rigger" wrote in message
oups.com...
And do you know where the wiring from the breaker goes before it gets
to the outlet? Some do-it-yourself electrician may have left a loose
wire nut somewhere.

Dennis in nca

As others have noted, check to see that you have not toasted the
breaker. There are some real trash manufacturers of breakers and panels,
some of the breakers will only take a few hard shorts before they act
like a fuse and burn out. Use a voltmeter to check for 120 at the
breaker terminal.

Check to see if you lost the hot or the neutral. On the bad outlet check
the voltage from the hot terminal (black or the narrow blade on the
outside) to ground (round pin). If you get 120 volts or so, you lost the
neutral side.

If that checks ok, you likely opened up a connection **upstream** from
the offending outlet. Classic case of problem and symptom in different
places. Map your circuits by turning off the offending circuit, find ALL
the outlets affected by the one in question. Then open up the closest
good outlet to either of the bad outlets. You may have to try several to
find the culprit.

Look for a wire nut that has one loose or burned wire, it could be
either the black or white/grey. If the outlet is wired as a through
point, you should see one pair of wires to upper set of terminals, the
other pair of wires to the lower set. If these are screws, tighten them.
If they are just pushed in the back, (ACK!!!, I HATE it when people use
those!), push them in and see if they wiggle.

Insert usual comments about working safe, you need to be super aware of
what you are doing if you have wires out, dangling, and exposed. Don't
stand on wet concrete while you do this sort of thing.

Mike Henry wrote:

I've got a dead circuit in the garage which worked fine until I plugged in a
new-to-me tool and apparently shorted the power switch to the machine base.
That created a noticeable spark at the tool and instant power loss to that
outlet. Unplugged the tool, popped downstairs to the main electrical panel
and reset a tripped breaker. Back upstairs but still no power to the outlet
or one other nearby.that is apparently on the same circuit. I turned off
all of the circuit breakers that were likely to power the blown circuit and
pulled the duplex recptacle ffrom the wall for inspection. It has two black
wires on the hot side and two gray wires on the neutral side. Ground is
apparently supplied through the conduit. No evidence of arcing or damage to
the receptacle and there was 40 M-ohm resistance across the hot and
neutral terminals. The receptacle was replaced with a new one, just in
case.

All of the circuit breakers were turned on in the panel, but there is still
no power to the outlet - voltage across the hot/neutral terminals is around
1 VAC. I checked all of the breakers again and they are all in the on
position.

I'm perplexed - what might be causing the problem?

Mike

On 2 Jul 2005 21:53:24 -0700, the renowned "rigger"
wrote:

And do you know where the wiring from the breaker goes before it gets
to the outlet? Some do-it-yourself electrician may have left a loose
wire nut somewhere.

Dennis in nca

I fixed a dead outlet in the (professionally wired) basement by
finding the junction where the electrician had nicked the wire. It
broke, leaving the outlet dead. It was a PITA to find, at least for
me.

I doubt that's the exact problem here, but if it was wired using the
push-in holes of receptacles it could have burned one of those in
another box.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

"Rick" wrote in message
ink.net...

"Mike Henry" wrote in message
...
I've got a dead circuit in the garage which worked fine until I
plugged in a
new-to-me tool and apparently shorted the power switch to the
machine base.
That created a noticeable spark at the tool and instant power loss
to that
outlet. Unplugged the tool, popped downstairs to the main
electrical panel
and reset a tripped breaker. Back upstairs but still no power to
the outlet
or one other nearby.that is apparently on the same circuit. I
turned off
all of the circuit breakers that were likely to power the blown
circuit and
pulled the duplex recptacle ffrom the wall for inspection. It has
two black
wires on the hot side and two gray wires on the neutral side.
Ground is
apparently supplied through the conduit. No evidence of arcing or
damage to
the receptacle and there was 40 M-ohm resistance across the hot
and
neutral terminals. The receptacle was replaced with a new one, just
in
case.

All of the circuit breakers were turned on in the panel, but there
is still
no power to the outlet - voltage across the hot/neutral terminals is
around
1 VAC. I checked all of the breakers again and they are all in the
on
position.

I'm perplexed - what might be causing the problem?

Mike

You sure there isn't a GFCI upstream of the outlet?






Be aware of a common GFCI "mousetrap." If the GFIC is wired backward, i.e.,
power connected to the output side and downstream outlets connected to the
input side, it will protect the downstream outlets, but not itself. In
other words, if it trips, the downstream will be dead, but it will have
power itself, leading one to conclude it is not the problem. If you have
GFCIs, it is a real good idea to hit the "test" button to trip it and then
check to make sure it is, itself, off.

Jerry

Thanks for all the suggestions.

As it turns out there is a GFCI in a bathroom adjacent to the garage that
had tripped and which apparently feeds the garage outlet. The GFCI outlet
is not used so we never noticed that it was tripped.

I got off on several tangents in trying to troubleshoot this. This is a
townhome that we purchased new and it looks like the electricians did a
fairly decent job (wires screwed to receptacle terminals) and there were no
worries about what another owner might have done. Aside from not
remembering the bath room GFCI, the main problem was that I couldn't figure
out which breaker was supplying power to the garage outlet and didn't want
to pull the receptacle until I was sure that the wires were unpowered. The
main panel breakers are labeled but a bit more obtusely than I would have
liked. There is a "garage" CB but it turns out to be on a different circuit
and the correct one is labeled only "GFI". I got sidetracked by a GFCI in a
utility room which seemed to be a logical tie point for the garage outlet
parttially because I noticed my wife had partially painted over the
recptacle slots. That was a red herring.

At one point I decided to check voltages from the outlet to hots and
neutrals on a known good circuit. I was getting 12-13 VAC on the hot &
neutral from one pair of wires to the outlet and 68-72 VAC from the other
pair of hot/neutral wires. Is that normal?

As an unexpected bonus, I did find one GFCI in the house that filed to test
properly. It's located directly below the main electrical panel between two
window wells. I replaced that one today.

Some time spent mapping CBs and circuits is probably in order against the
next time something like this happens.

Mike

"RoyJ" wrote in message
k.net...
As others have noted, check to see that you have not toasted the breaker.
There are some real trash manufacturers of breakers and panels, some of
the breakers will only take a few hard shorts before they act like a fuse
and burn out. Use a voltmeter to check for 120 at the breaker terminal.

Check to see if you lost the hot or the neutral. On the bad outlet check
the voltage from the hot terminal (black or the narrow blade on the
outside) to ground (round pin). If you get 120 volts or so, you lost the
neutral side.

If that checks ok, you likely opened up a connection **upstream** from the
offending outlet. Classic case of problem and symptom in different places.
Map your circuits by turning off the offending circuit, find ALL the
outlets affected by the one in question. Then open up the closest good
outlet to either of the bad outlets. You may have to try several to find
the culprit.

Look for a wire nut that has one loose or burned wire, it could be either
the black or white/grey. If the outlet is wired as a through point, you
should see one pair of wires to upper set of terminals, the other pair of
wires to the lower set. If these are screws, tighten them. If they are
just pushed in the back, (ACK!!!, I HATE it when people use those!), push
them in and see if they wiggle.

Insert usual comments about working safe, you need to be super aware of
what you are doing if you have wires out, dangling, and exposed. Don't
stand on wet concrete while you do this sort of thing.

Mike Henry wrote:

I've got a dead circuit in the garage which worked fine until I plugged
in a new-to-me tool and apparently shorted the power switch to the
machine base. That created a noticeable spark at the tool and instant
power loss to that outlet. Unplugged the tool, popped downstairs to the
main electrical panel and reset a tripped breaker. Back upstairs but
still no power to the outlet or one other nearby.that is apparently on
the same circuit. I turned off all of the circuit breakers that were
likely to power the blown circuit and pulled the duplex recptacle ffrom
the wall for inspection. It has two black wires on the hot side and two
gray wires on the neutral side. Ground is apparently supplied through
the conduit. No evidence of arcing or damage to the receptacle and there
was 40 M-ohm resistance across the hot and neutral terminals. The
receptacle was replaced with a new one, just in case.

All of the circuit breakers were turned on in the panel, but there is
still no power to the outlet - voltage across the hot/neutral terminals
is around 1 VAC. I checked all of the breakers again and they are all in
the on position.

I'm perplexed - what might be causing the problem?

Mike

"Mike Henry" wrote in message
...
Thanks for all the suggestions.

As it turns out there is a GFCI in a bathroom adjacent to the garage
that
had tripped and which apparently feeds the garage outlet. The GFCI
outlet
is not used so we never noticed that it was tripped.

I got off on several tangents in trying to troubleshoot this. This
is a
townhome that we purchased new and it looks like the electricians
did a
fairly decent job (wires screwed to receptacle terminals) and there
were no
worries about what another owner might have done. Aside from not
remembering the bath room GFCI, the main problem was that I couldn't
figure
out which breaker was supplying power to the garage outlet and
didn't want
to pull the receptacle until I was sure that the wires were
unpowered. The
main panel breakers are labeled but a bit more obtusely than I would
have
liked. There is a "garage" CB but it turns out to be on a different
circuit
and the correct one is labeled only "GFI". I got sidetracked by a
GFCI in a
utility room which seemed to be a logical tie point for the garage
outlet
parttially because I noticed my wife had partially painted over the
recptacle slots. That was a red herring.

At one point I decided to check voltages from the outlet to hots
and
neutrals on a known good circuit. I was getting 12-13 VAC on the
hot &
neutral from one pair of wires to the outlet and 68-72 VAC from the
other
pair of hot/neutral wires. Is that normal?

Did you use a digital voltmeter to measure this by any chance?

"Rick" wrote in message
link.net...

"Mike Henry" wrote in message
...
Thanks for all the suggestions.

As it turns out there is a GFCI in a bathroom adjacent to the garage
that
had tripped and which apparently feeds the garage outlet. The GFCI
outlet
is not used so we never noticed that it was tripped.

I got off on several tangents in trying to troubleshoot this. This
is a
townhome that we purchased new and it looks like the electricians
did a
fairly decent job (wires screwed to receptacle terminals) and there
were no
worries about what another owner might have done. Aside from not
remembering the bath room GFCI, the main problem was that I couldn't
figure
out which breaker was supplying power to the garage outlet and
didn't want
to pull the receptacle until I was sure that the wires were
unpowered. The
main panel breakers are labeled but a bit more obtusely than I would
have
liked. There is a "garage" CB but it turns out to be on a different
circuit
and the correct one is labeled only "GFI". I got sidetracked by a
GFCI in a
utility room which seemed to be a logical tie point for the garage
outlet
parttially because I noticed my wife had partially painted over the
recptacle slots. That was a red herring.

At one point I decided to check voltages from the outlet to hots
and
neutrals on a known good circuit. I was getting 12-13 VAC on the
hot &
neutral from one pair of wires to the outlet and 68-72 VAC from the
other
pair of hot/neutral wires. Is that normal?

Did you use a digital voltmeter to measure this by any chance?


Yep, it was a digital VOM - would analog have given different results?

Yes, an analog volt meter is definitely more reliable than a lot of DMMs for
AC volts.

With a DMM sitting on a table, not connected to any circuit, you might
notice that if you only hold a single meter lead tip with your fingers, that
the reading jumps around.

A quick check for the relative quality of a DMM is to set it on the lowest
voltage range with no leads attached. The display should be zero or a very
low reading that doesn't fluctuate. Fluctuation can indicate that there is
no shielding, or that it's inadequate, and some low-end meters are the
worst.

Depending upon the design of the DMM meter's input and conversion circuitry,
the readings can be very unreliable, especially when checking for AC
voltages.

Generally, the only analog AC meters that will give unusual-looking
readings, are the amplified ones that are intended to measure very small
potentials in the micro or millivolt potentials (not for AC house/building
wiring troubleshooting).

WB
...............

"Mike Henry" wrote in message
...

Did you use a digital voltmeter to measure this by any chance?


Yep, it was a digital VOM - would analog have given different results?






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"Ghost" AC voltages can often be seen with analog as well as digital VMs.
The situation is related to the extremely high impedance of most "service
type" VMs. They are designed to impose very small loading on the circuit
under test. This is fine when testing electronic devices but can be
misleading on ordinary AC power circuits. The cause is leakage. The source
of most home power is a center tap (grounded) transformer with 120VAC
circuits taken from both ends. Insulation leakage anywhere in home
distribution, esp. across "open" breaker contacts, can give erroneous
readings on ordinary voltmeters.

Bob Swinney

"Wild Bill" wrote in message
...
Yes, an analog volt meter is definitely more reliable than a lot of DMMs
for
AC volts.

With a DMM sitting on a table, not connected to any circuit, you might
notice that if you only hold a single meter lead tip with your fingers,
that
the reading jumps around.

A quick check for the relative quality of a DMM is to set it on the lowest
voltage range with no leads attached. The display should be zero or a very
low reading that doesn't fluctuate. Fluctuation can indicate that there is
no shielding, or that it's inadequate, and some low-end meters are the
worst.

Depending upon the design of the DMM meter's input and conversion
circuitry,
the readings can be very unreliable, especially when checking for AC
voltages.

Generally, the only analog AC meters that will give unusual-looking
readings, are the amplified ones that are intended to measure very small
potentials in the micro or millivolt potentials (not for AC house/building
wiring troubleshooting).

WB
..............

"Mike Henry" wrote in message
...

Did you use a digital voltmeter to measure this by any chance?


Yep, it was a digital VOM - would analog have given different results?






----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet
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Newsgroups
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=----

Glad you isolated your problem. Just a comment about digital meters: A low
battery can give bad readings.

Ace


"Mike Henry" wrote in message
...

"Rick" wrote in message
link.net...

"Mike Henry" wrote in message
...
Thanks for all the suggestions.

As it turns out there is a GFCI in a bathroom adjacent to the garage
that
had tripped and which apparently feeds the garage outlet. The GFCI
outlet
is not used so we never noticed that it was tripped.

I got off on several tangents in trying to troubleshoot this. This
is a
townhome that we purchased new and it looks like the electricians
did a
fairly decent job (wires screwed to receptacle terminals) and there
were no
worries about what another owner might have done. Aside from not
remembering the bath room GFCI, the main problem was that I couldn't
figure
out which breaker was supplying power to the garage outlet and
didn't want
to pull the receptacle until I was sure that the wires were
unpowered. The
main panel breakers are labeled but a bit more obtusely than I would
have
liked. There is a "garage" CB but it turns out to be on a different
circuit
and the correct one is labeled only "GFI". I got sidetracked by a
GFCI in a
utility room which seemed to be a logical tie point for the garage
outlet
parttially because I noticed my wife had partially painted over the
recptacle slots. That was a red herring.

At one point I decided to check voltages from the outlet to hots
and
neutrals on a known good circuit. I was getting 12-13 VAC on the
hot &
neutral from one pair of wires to the outlet and 68-72 VAC from the
other
pair of hot/neutral wires. Is that normal?

Did you use a digital voltmeter to measure this by any chance?


Yep, it was a digital VOM - would analog have given different results?

In this same vein those neon circuit testers are worthless and
potentially dangerous because they can give erroneous readings.
Capacitive coupling and leakage give these. There was an article in
Electrical Contracting and Maint. several years ago. It's gist was that
they were only good for night lights.

Chuck P.

They can also be connected between your fingers and the wire to identify the
hot wire in knob-and-tube wiring in the attic where no ground is within
reach. That function is probably not very useful nowadays.
Don Young

"MOP CAP" wrote in message
news:040720051133066260%Pilgrim6nospam@mindspring. com...
In this same vein those neon circuit testers are worthless and
potentially dangerous because they can give erroneous readings.
Capacitive coupling and leakage give these. There was an article in
Electrical Contracting and Maint. several years ago. It's gist was that
they were only good for night lights.

Chuck P.

On Mon, 04 Jul 2005 18:16:40 GMT, "Ace"
wrote:

Glad you isolated your problem. Just a comment about digital meters: A low
battery can give bad readings.

Ace

And a hundred thousand ohms or two of resistance between the leads
usually kills the spurious readings - keeps Zero at Zero.
Take the resistor off when you need the high accuracy and impedence.

"Mike Henry" wrote in message
...

"Rick" wrote in message
link.net...

"Mike Henry" wrote in message
...
Thanks for all the suggestions.

As it turns out there is a GFCI in a bathroom adjacent to the garage
that
had tripped and which apparently feeds the garage outlet. The GFCI
outlet
is not used so we never noticed that it was tripped.

I got off on several tangents in trying to troubleshoot this. This
is a
townhome that we purchased new and it looks like the electricians
did a
fairly decent job (wires screwed to receptacle terminals) and there
were no
worries about what another owner might have done. Aside from not
remembering the bath room GFCI, the main problem was that I couldn't
figure
out which breaker was supplying power to the garage outlet and
didn't want
to pull the receptacle until I was sure that the wires were
unpowered. The
main panel breakers are labeled but a bit more obtusely than I would
have
liked. There is a "garage" CB but it turns out to be on a different
circuit
and the correct one is labeled only "GFI". I got sidetracked by a
GFCI in a
utility room which seemed to be a logical tie point for the garage
outlet
parttially because I noticed my wife had partially painted over the
recptacle slots. That was a red herring.

At one point I decided to check voltages from the outlet to hots
and
neutrals on a known good circuit. I was getting 12-13 VAC on the
hot &
neutral from one pair of wires to the outlet and 68-72 VAC from the
other
pair of hot/neutral wires. Is that normal?

Did you use a digital voltmeter to measure this by any chance?


Yep, it was a digital VOM - would analog have given different results?

On Mon, 4 Jul 2005 22:29:24 -0500, "Don Young"
wrote:

They can also be connected between your fingers and the wire to identify the
hot wire in knob-and-tube wiring in the attic where no ground is within
reach. That function is probably not very useful nowadays.
Don Young

"MOP CAP" wrote in message
news:040720051133066260%Pilgrim6nospam@mindspring .com...
In this same vein those neon circuit testers are worthless and
potentially dangerous because they can give erroneous readings.
Capacitive coupling and leakage give these. There was an article in
Electrical Contracting and Maint. several years ago. It's gist was that
they were only good for night lights.

Chuck P.

Bought a neon tester some years ago - screwdriver with insulated
shaft, exposed blade, neon tube in the handle connected between the
shaft and the pocket clip. I doubt that these are available now.
Gerry :-)}
London, Canada

I guess I expected something other than absolute zero VAC, but 14 and 70 VAC
had me a bit concerned. Without cause apparently.

Your "no lead" test was interesting. The Tenma (import from Gaingers,
probably) that I was using most of the time is an autoranging DMM and reads
around 1-2 MV. An old Heathkit (an actual kit) from around 30 years ago
reads 0.1-0.2 MV reads exactly 0 on all of it's ranges. Guess I'll use the
Heathkit next time and maybe look around for an analog in good shape.

Is Simpson a good brand?

Mike


"Wild Bill" wrote in message
...
Yes, an analog volt meter is definitely more reliable than a lot of DMMs
for
AC volts.

With a DMM sitting on a table, not connected to any circuit, you might
notice that if you only hold a single meter lead tip with your fingers,
that
the reading jumps around.

A quick check for the relative quality of a DMM is to set it on the lowest
voltage range with no leads attached. The display should be zero or a very
low reading that doesn't fluctuate. Fluctuation can indicate that there is
no shielding, or that it's inadequate, and some low-end meters are the
worst.

Depending upon the design of the DMM meter's input and conversion
circuitry,
the readings can be very unreliable, especially when checking for AC
voltages.

Generally, the only analog AC meters that will give unusual-looking
readings, are the amplified ones that are intended to measure very small
potentials in the micro or millivolt potentials (not for AC house/building
wiring troubleshooting).

WB
..............

"Mike Henry" wrote in message
...

Did you use a digital voltmeter to measure this by any chance?


Yep, it was a digital VOM - would analog have given different results?






----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet
News==----
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Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption
=----

Bob,

Hopefully that will stick in the noggin. What's a good brand of analog DVM
or DMM for these sorts of situations?

Mike

"Robert Swinney" wrote in message
...
"Ghost" AC voltages can often be seen with analog as well as digital VMs.
The situation is related to the extremely high impedance of most "service
type" VMs. They are designed to impose very small loading on the circuit
under test. This is fine when testing electronic devices but can be
misleading on ordinary AC power circuits. The cause is leakage. The
source of most home power is a center tap (grounded) transformer with
120VAC circuits taken from both ends. Insulation leakage anywhere in home
distribution, esp. across "open" breaker contacts, can give erroneous
readings on ordinary voltmeters.

Bob Swinney

"Wild Bill" wrote in message
...
Yes, an analog volt meter is definitely more reliable than a lot of DMMs
for
AC volts.

With a DMM sitting on a table, not connected to any circuit, you might
notice that if you only hold a single meter lead tip with your fingers,
that
the reading jumps around.

A quick check for the relative quality of a DMM is to set it on the
lowest
voltage range with no leads attached. The display should be zero or a
very
low reading that doesn't fluctuate. Fluctuation can indicate that there
is
no shielding, or that it's inadequate, and some low-end meters are the
worst.

Depending upon the design of the DMM meter's input and conversion
circuitry,
the readings can be very unreliable, especially when checking for AC
voltages.

Generally, the only analog AC meters that will give unusual-looking
readings, are the amplified ones that are intended to measure very small
potentials in the micro or millivolt potentials (not for AC
house/building
wiring troubleshooting).

WB
..............

"Mike Henry" wrote in message
...

Did you use a digital voltmeter to measure this by any chance?


Yep, it was a digital VOM - would analog have given different results?






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Your checkout readings from the Tenma model are pretty good. It's definitely
annoying when DMMs hunt for a reading.
Tenma was a generic/clone product company that's turned into a fairly widely
recognized brand name.
The no-name brands that sell in about the $6 and up range are what quite a
few sellers are offering lately. The term digital doesn't assure accuracy,
and doesn't much matter if the device is a DMM or a bathroom scale.

A good practice is to take test readings of known voltages before circuit
testing begins. When weird/unexpected readings are encountered, the user
needs to determine why, to be able to proceed safely.

Simpson, Triplett, Weston have all made durable, reliable analog meters (and
most still do).
Older analog or digital meters are great if you're the original owner, that
way you could be sure that they haven't been OV'd or abused. I still have a
working one that was new in about '73.
Aged meters (decades) shouldn't be expected to be as accurate as when they
were manufactured because component values will drift with age, but their
durability is their real value (and they can often be recalibrated or
repaired to their original accuracy).
For home/shop wiring voltages, an error of a few volts isn't very critical.

Beckman made some of the highest quality DMMs, although they're produced
under Wavetek now (and look like a design school project for a TV/VCR/?
all-in-one all purpose remote control).
The Beckman Industrial 100-4000 series were extremely well built. Not many
handheld DMMs had a 1000-1500VAC range, which is important for 460+ 3-phase
AC (because the phase-phase peaks exceed the 750VAC maximum input of meters
with a 750AC max. range).
Old Beckman DMMs can be problematic.. the switches may have become oxidized,
or the LCD holders may not be as tight as neccessary to maintain
consistently clear readings (missing display segments).

WB
.................

"Mike Henry" wrote in message
...
I guess I expected something other than absolute zero VAC, but 14 and 70
VAC
had me a bit concerned. Without cause apparently.

Your "no lead" test was interesting. The Tenma (import from Gaingers,
probably) that I was using most of the time is an autoranging DMM and
reads
around 1-2 MV. An old Heathkit (an actual kit) from around 30 years ago
reads 0.1-0.2 MV reads exactly 0 on all of it's ranges. Guess I'll use
the
Heathkit next time and maybe look around for an analog in good shape.

Is Simpson a good brand?

Mike


"Wild Bill" wrote in message
...
Yes, an analog volt meter is definitely more reliable than a lot of DMMs
for
AC volts.

With a DMM sitting on a table, not connected to any circuit, you might
notice that if you only hold a single meter lead tip with your fingers,
that
the reading jumps around.

A quick check for the relative quality of a DMM is to set it on the
lowest
voltage range with no leads attached. The display should be zero or a
very
low reading that doesn't fluctuate. Fluctuation can indicate that there
is
no shielding, or that it's inadequate, and some low-end meters are the
worst.

Depending upon the design of the DMM meter's input and conversion
circuitry,
the readings can be very unreliable, especially when checking for AC
voltages.

Generally, the only analog AC meters that will give unusual-looking
readings, are the amplified ones that are intended to measure very small
potentials in the micro or millivolt potentials (not for AC
house/building
wiring troubleshooting).

WB
..............




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