I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Thanks.
--
John English

On Sat, 4 Jul 2009 23:40:18 -0700, the renowned John E.
wrote:

I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Thanks.

IMO, 11% high voltage over nominal should not "fry" the controller
board in the first place.


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

On Sun, 05 Jul 2009 02:58:00 -0400, Spehro Pefhany
wrote:

On Sat, 4 Jul 2009 23:40:18 -0700, the renowned John E.
wrote:

I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Thanks.

IMO, 11% high voltage over nominal should not "fry" the controller
board in the first place.



Yes. The controller was overly fragile, or it may have just had a
random failure unrelated to supply voltage. That happens.

If the owner blames the electrician, don't use him again. Sue the
power company for providing 245.


John

John Larkin wrote:

On Sun, 05 Jul 2009 02:58:00 -0400, Spehro Pefhany
wrote:


On Sat, 4 Jul 2009 23:40:18 -0700, the renowned John E.
wrote:


I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Thanks.

IMO, 11% high voltage over nominal should not "fry" the controller
board in the first place.




Yes. The controller was overly fragile, or it may have just had a
random failure unrelated to supply voltage. That happens.

If the owner blames the electrician, don't use him again. Sue the
power company for providing 245.


John

You can only do that if the electric company is actually providing that
245V.
It's possible they are providing 480/460 V 3 Phase, and a in house
transformer is being used. If that is the case, then there should be
taps on the primary side to adjust this how ever, this measurement
must be taken with at least 50% load of the shop on it to get a true
reading.

245V is not uncommon and shouldn't cause any issues, actually,
induction motors run better on peppier voltages.


I may sound like I'm getting fired up over this with multiple reply's
I have made, it's nothing against you John how ever, this comes from
events that I have seen take place at work where expensive electronics
just went faulty on normal use and caused a lot of down time and
material loss. The powers to be that don't know anything about the field
start pointing fingers and when they research to see who was the last one
to have their hands in the machine no matter how long ago it was. They
think its a good justification to start blame storming. Some time people
loss their jobs when they did absolutely nothing wrong only to save the
ass of some one else!.

On 5 Jul., 08:58, Spehro Pefhany
wrote:
On Sat, 4 Jul 2009 23:40:18 -0700, the renowned John E.



wrote:
I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Thanks.

IMO, 11% high voltage over nominal should not "fry" the controller
board in the first place. *


a loose neutral can result in all kinds of strange voltages depending
on the load on the
phases, so the 11% might just be what the voltage was when it was
measured, not what
it was when the controller was fried

-Lasse

"John E."

I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but
has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the
CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?


** What a STUPID troll !!!

The PSU in the CNC blew cos it was a pile of **** PLUS the design was 100%
incompetant cos it gave no protection to the delicate and expensive load.

Bet it was old and way past use by date too.

**** off TROLL !!


..... Phil

On Sun, 5 Jul 2009 17:13:32 +1000, "Phil Allison"
wrote:


"John E."

I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but
has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the
CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?


** What a STUPID troll !!!

The PSU in the CNC blew cos it was a pile of **** PLUS the design was 100%
incompetant cos it gave no protection to the delicate and expensive load.

Bet it was old and way past use by date too.

**** off TROLL !!


.... Phil


Probably a good call, since modern switchers, which the DC supplies
for these things usually are, can handle up to about 265 volts. Even a
bit more, typically.

"Archimedes' Lever"
"Phil Allison"

"John E."

I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring
(3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but
has
done shop wiring before and had a good attitude and track record. The
guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the
CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?


** What a STUPID troll !!!

The PSU in the CNC blew cos it was a pile of **** PLUS the design was
100%
incompetant cos it gave no protection to the delicate and expensive load.

Bet it was old and way past use by date too.

**** off TROLL !!


Probably a good call, since modern switchers, which the DC supplies
for these things usually are, can handle up to about 265 volts. Even a
bit more, typically.


** Unlikely it was a SMPS based on the OP's admittedly poor and incomplete
info.

Cos SMPS do not have multi-taps for AC input voltage - PLUS if an
off-line switcher fails from overvoltage, it just blows the fuse and goes
dead.

But losing regulation and over-voltaging the load ( as was alleged by the
OP) is another scenario altogether - more often associated with old age or
the failure of one of a few critical components in the regulation loop.



...... Phil

On Sat, 4 Jul 2009 23:40:18 -0700, John E.
wrote:

I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

The nominal utility power as supplied is supposed to be 240V. 5
volts over is a touch hot, but not out of the bounds of normal
tolerances - turn everything on in the neighborhood some hot August
afternoon with the AC units cranked, and tell me what the voltage
reads then...

If they were seeing 250V - 255V or more, then I'd call the Utility
and get the transformer taps knocked down a notch.

If the power supply on the CNC computer had changeable taps, and the
last guy that touched it didn't have any reason to look to see what it
was set for, IMHO it's nobody's fault. Especially if the shop they
moved from and the one they moved to had the same nominal operating
voltage, and they knew it - I'm not going to open 50 machines looking
for the unexpected when I'm charging by the hour unless I have a good
reason to... Just "Git Er Done" and go home.

If he had a reason to look inside and saw it was on the 220V tap he
should have moved it to the 240V - or told the owner - it's good
practice to follow but there's no responsibility to look involved.

And I wouldn't expect 255V on the 220V tap to kill it. Now if it
was set for 208V input and you fed it off the 'High Leg' from an Open
Delta service that's hovering around 280V to ground, THEN I'd expect
fireworks. Open Delta High Leg voltages can bounce around and go even
higher, then something flashes over...

That would be the /one/ time I'd call it against the Handyman,
putting the high leg on the control circuit would be a big goof. You
are supposed to put the regular 240V legs on the A and C phases coming
in, and the 'High Leg' Orange lead to B phase and NOT the controls.

The average power supply is supposed to feed +5V, +12V & -12V etc.
to the computer board, and have Crowbar protection so that's all that
gets through. If the supply blows up and lets line voltage through to
fry the controller board (even if you put an over-voltage on the
input) that's a badly built power supply.

Otherwise, it's entirely possible that it just reached End Of Life
and decided to go out in a spectacular manner, and the move had
nothing to do with it. The timer that makes things blow up three days
out of warranty finally went off.

Unless you want to spend a lot of money on Electronic Forensics to
analyze the power supply failure, "The world may never know..."

-- Bruce --

PS - Have to trim off alt-r.c.m to make this go, 4 crosspost limit.

Bruce L. Bergman wrote:

The nominal utility power as supplied is supposed to be 240V. 5
volts over is a touch hot, but not out of the bounds of normal
tolerances - turn everything on in the neighborhood some hot August
afternoon with the AC units cranked, and tell me what the voltage
reads then...

If they were seeing 250V - 255V or more, then I'd call the Utility
and get the transformer taps knocked down a notch.

My drier sees 250VAC. Low voltage stuff in this house gets 125VAC.

Everything is working just fine.

Jon

My drier sees 250VAC. Low voltage stuff in this house gets 125VAC.
Everything is working just fine.

sniff sniff Is that burning cotton I smell?

William Sommerwerck wrote:
My drier sees 250VAC. Low voltage stuff in this house gets 125VAC.
Everything is working just fine.

sniff sniff Is that burning cotton I smell?

Drier has a temperature limiter, so although the slightly higher voltage
results in a slightly quicker "turn on" time for the elements, they still
are shut off at the same temperature regardless of incoming voltage.

Jon

"Jon Danniken" wrote in message
...
William Sommerwerck wrote:


My drier sees 250VAC. Low voltage stuff in this house gets 125VAC.
Everything is working just fine.

sniff sniff Is that burning cotton I smell?


Drier has a temperature limiter,

It's called a thermostat

so although the slightly higher voltage
results in a slightly quicker "turn on" time for the elements, they still
are shut off at the same temperature regardless of incoming voltage.

Of course. I was jesting.

Jon Danniken wrote:
William Sommerwerck wrote:
My drier sees 250VAC. Low voltage stuff in this house gets 125VAC.
Everything is working just fine.
sniff sniff Is that burning cotton I smell?

Drier has a temperature limiter, so although the slightly higher voltage
results in a slightly quicker "turn on" time for the elements, they still
are shut off at the same temperature regardless of incoming voltage.

Jon




I rented a house for a while that had unusually high line voltage. It
varied from around 122V to 125V depending on the time of day. If it was
much higher than that, I'd be concerned, but anything from 115V to 125V
is pretty normal.

A friend of mine over in the UK is near the end of a long run from the
transformer that powers his street. His voltage varies considerably,
from as low as 220V to nearly 250V.

Bruce L. Bergman wrote:
On Sat, 4 Jul 2009 23:40:18 -0700, John E.
wrote:

I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

The nominal utility power as supplied is supposed to be 240V. 5
volts over is a touch hot, but not out of the bounds of normal
tolerances - turn everything on in the neighborhood some hot August
afternoon with the AC units cranked, and tell me what the voltage
reads then...




That is not always the case. I'm a little rusty when it comes to 3 phase
distribution, but I've dealt with some things like this in a machine
shop friends of mine own. The voltage depends on the service to the
building. Some shops have 208V and some have 240V, and we've had to
reconfigure machines from time to time that were purchased from other
locations, or run some off buck/boost transformers if they were not
configurable. Perhaps someone more knowledgeable can fill in the details.

It's good practice of course to measure the voltage and double check the
configuration of the particular machine prior to applying power.

$4K seems pretty high though, did anyone look into repairing the damaged
board?

On Sun, 05 Jul 2009 15:33:48 -0700, James Sweet
wrote:

Bruce L. Bergman wrote:
On Sat, 4 Jul 2009 23:40:18 -0700, John E.
wrote:

I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

The nominal utility power as supplied is supposed to be 240V. 5
volts over is a touch hot, but not out of the bounds of normal
tolerances - turn everything on in the neighborhood some hot August
afternoon with the AC units cranked, and tell me what the voltage
reads then...




That is not always the case. I'm a little rusty when it comes to 3 phase
distribution, but I've dealt with some things like this in a machine
shop friends of mine own. The voltage depends on the service to the
building. Some shops have 208V and some have 240V, and we've had to
reconfigure machines from time to time that were purchased from other
locations, or run some off buck/boost transformers if they were not
configurable. Perhaps someone more knowledgeable can fill in the details.

It's good practice of course to measure the voltage and double check the
configuration of the particular machine prior to applying power.

$4K seems pretty high though, did anyone look into repairing the damaged
board?

CNC electronics cost about 4-8 times as much to fix as normal
electronics. Shrug..its called :"the going rate" unfortunately.

Gunner

"Lenin called them "useful idiots," those people living in
liberal democracies who by giving moral and material support
to a totalitarian ideology in effect were braiding the rope that
would hang them. Why people who enjoyed freedom and prosperity worked
passionately to destroy both is a fascinating question, one still with us
today. Now the useful idiots can be found in the chorus of appeasement,
reflexive anti-Americanism, and sentimental idealism trying to inhibit
the necessary responses to another freedom-hating ideology, radical Islam"

Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno

On Sun, 05 Jul 2009 16:40:10 -0700, Gunner Asch
wrote:

CNC electronics cost about 4-8 times as much to fix as normal
electronics. Shrug..its called :"the going rate" unfortunately.

Motor controllers are 70s technology with MAYBE 90s electronics, if you
are lucky. Even if it is a brand new design, it still isn't worth
anything more than any other industrial application.

$4000 is a bit much for a simple swap out.

Perhaps it is guys like you that have inflated the price over the
years. Overt greed is such a sad thing. It produces jerks that thumb
their noses at the entire industrial world, then cannot figure out why
God handed you a heart condition.

I guess that's what they all deserve for buying Japanese CNC hardware.

Buy American. I'll bet that one of Cincinnati Milacron's controller
boards do not cast that much.

Laugh laugh laugh? You say? I laugh at you, jackass.

I say that I hope that chest gripper of death hits you soon, because
you are a major Asch hole.

On Mon, 06 Jul 2009 01:11:46 -0700, Archimedes' Lever
wrote:

On Sun, 05 Jul 2009 16:40:10 -0700, Gunner Asch
wrote:

CNC electronics cost about 4-8 times as much to fix as normal
electronics. Shrug..its called :"the going rate" unfortunately.

Motor controllers are 70s technology with MAYBE 90s electronics, if you
are lucky. Even if it is a brand new design, it still isn't worth
anything more than any other industrial application.

$4000 is a bit much for a simple swap out.

Yes it is indeed. Take that up with the Japanese btw..and their US
agents.

Perhaps it is guys like you that have inflated the price over the
years. Overt greed is such a sad thing. It produces jerks that thumb
their noses at the entire industrial world, then cannot figure out why
God handed you a heart condition.

My greed? Hummm perhaps you havent any idea that Im one of the cheapest
CNC service techs in So. Cal? Or is it simply that Im A service tech
that busts your chops?
Or are you simply an argumentative Leftwing piece of **** who doesnt
like anyone to the Right of Trotsky? Powa to da Pipples!!!

I guess that's what they all deserve for buying Japanese CNC hardware.

Buy American. I'll bet that one of Cincinnati Milacron's controller
boards do not cast that much.

How much do you care to wager on that? Be specific......I could use a
nice score. But then..it would appear you are a Leftwinger..and you
would lose, whimper and whine, and then steal someone elses money if I
held a gun to your head and made you pay up on your bet.

Laugh laugh laugh? You say? I laugh at you, jackass.

yawn

I say that I hope that chest gripper of death hits you soon, because
you are a major Asch hole.

And I hope you have a nice day too.

Gunner, off to LA to finish taking apart a factory


"Lenin called them "useful idiots," those people living in
liberal democracies who by giving moral and material support
to a totalitarian ideology in effect were braiding the rope that
would hang them. Why people who enjoyed freedom and prosperity worked
passionately to destroy both is a fascinating question, one still with us
today. Now the useful idiots can be found in the chorus of appeasement,
reflexive anti-Americanism, and sentimental idealism trying to inhibit
the necessary responses to another freedom-hating ideology, radical Islam"

Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno

On Jul 5, 2:40 am, John E. wrote:
Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

As others have said, there's not much the wiring guy could have done
wrong to get 245 volts rather than 220. He hooked up what was there
and couldn't be expected to have detailed knowledge of what the owner
was going to run, what setting he had it on or how sensitive it was.

Does the owner have some reason to believe that this was not the
voltage in the new shop before the additions?

On Sun, 5 Jul 2009 02:04:47 -0700 (PDT), Larry The Snake Guy
wrote:

He hooked up what was there
and couldn't be expected to have detailed knowledge of what the owner
was going to run,

You're an idiot. If you are wiring POWER runs, you had better know
what your loads are, and how they get connected.

John E. writes:

What is the legal and moral responsibility of each party?

None. It is George Bush's fault.

John E wrote:

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

It is the owner of the shop to make sure the electrician he hired was licensed
and if needed insured. Since you did not say where this happened, I can only
make a blanket statement.

If the "guy" represneted himself as a licensed electrictian, then there may
be some criminal liability here for fraud. If he did not claim to be licensed,
or the owner of the business knew that he was not licensed, he is free and
clear.

If the owner hired him knowing he was not licensed, then it was his
responsability to hire a licensed electrician to inspect the work before
he "threw the switch". If he did not, he may be subject to criminal and
civil penalties, have his electricity turned off, etc.


Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.


And how do you know that? What device did you use to measure the voltage.
Assuming the voltmeter was accurate to 2% and rounded up, 240 volts would read
245. The difference is negligable anyway.

As for the voltage setting on the device, it's not the "wiring guy's" job.

Would you want some random "handyman" poking around inside of an expensive
CNC machine?

What is the legal and moral responsibility of each party?

I am not a lawyer, but from my (mis)understanding, as long as the "guy" did
not represent himself as an expert on the machine in question, or as a licensed
electrician, ALL of the responsability falls on the owner of the business and
none on the "guy" or anyone's insurance company.


What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Well, I'm going to make one. If the "guy" was up front about his not being
licensed, nor trained on the insides of the CNC machine, he is of good
character and reasonable intelligence.

Let's just say that the person who hired him was also of good character and
intelligence, but ignorant of the law and the requirments of equipment.

He's lucky that all he suffered was one $4000 board failing, not his
entire factory burning down around him with no insurance.

If in the future, he does not hire a licensed electrician to perform the
necessary inspections, etc, nor a properly trained technician to inspect
the equipment, you can say something very different.

I also think it is fair to assume that he has by now had a licensed electrician
in to inspect the work, and a trained technicain in to check all of his
equipment. If he has not done both.........


BTW, if both locations are connected to the same "power grid", it is
unlikely that the line voltage was 220 volts in the old location and 240
in the new one.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

In article , wrote:

BTW, if both locations are connected to the same "power grid", it is
unlikely that the line voltage was 220 volts in the old location and 240
in the new one.

Incorrect. Distribution voltages are on the order of a few thousand volts,
stepped down by transformers at the point of service to a few hundred. New
location = different transformer = possibly different service voltage even if
the distribution voltages are exactly the same.

That said, though.... any device designed for 220V should be able to handle
245V.

Doug Miller wrote:

Incorrect. Distribution voltages are on the order of a few thousand volts,
stepped down by transformers at the point of service to a few hundred. New
location = different transformer = possibly different service voltage even if
the distribution voltages are exactly the same.

Yes, BUT, a power company attempts to keep a constant voltage throught their
service area. While the voltage fluctates due to equipment, load, etc, I don't
think you can honestly say that if it is 220 volts on one side of town, the
same "grid" produces 240 on the other side of town. It might be 242 in one
place and 239 in another, but even that's a big difference unless there is
a heavy load in one location and not another.

The EU spec allowing household line voltage to be 240 volts while claiming 230
was to allow the UK to keep their current system while being "in spec" but I
doubt it was intended to allow variations from as much as 220 in one place
and 240 in another within the same country.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

In article , wrote:
Doug Miller wrote:

Incorrect. Distribution voltages are on the order of a few thousand volts,
stepped down by transformers at the point of service to a few hundred. New
location = different transformer = possibly different service voltage even if
the distribution voltages are exactly the same.

Yes, BUT, a power company attempts to keep a constant voltage throught their
service area. While the voltage fluctates due to equipment, load, etc, I don't
think you can honestly say that if it is 220 volts on one side of town, the
same "grid" produces 240 on the other side of town. It might be 242 in one
place and 239 in another, but even that's a big difference unless there is
a heavy load in one location and not another.

You're missing the point. This has nothing to do with the voltage supplied
by the utility. The utility doesn't supply 220V or 240V or whatever. They
supply (for example) 4KV. A transformer at the point of service reduces that
to 220V, or 240V, or whatever. Different transformers connected to the *same*
4KV primary voltage could easily produce different secondary voltages.

Doug Miller wrote:
You're missing the point. This has nothing to do with the voltage supplied
by the utility. The utility doesn't supply 220V or 240V or whatever. They
supply (for example) 4KV. A transformer at the point of service reduces that
to 220V, or 240V, or whatever. Different transformers connected to the *same*
4KV primary voltage could easily produce different secondary voltages.

No, I'm not. When I lived in the US, (PECO) the electric company sold
me 240 volt 2 phase electricity. It was nominaly 127 volts, but often
dropped down during times of high usage.

They did not supply or sell me 4kv volts, or anything else.

Here it's even simpler. Israel electric sells me 230 volts, 50Hz electicity
and except for just before the power going out it has been that way for 12
years. When I had a UPS monitoring the voltage, it was never more than
1 volt +- spec.

Ok, since you insist would anyone out there who gets 4kv from their local
electric company please raise your hand.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

On Sun, 05 Jul 2009 16:53:25 GMT, (Doug Miller)
wrote:


You're missing the point. This has nothing to do with the voltage supplied
by the utility. The utility doesn't supply 220V or 240V or whatever. They
supply (for example) 4KV. A transformer at the point of service reduces that
to 220V, or 240V, or whatever. Different transformers connected to the *same*
4KV primary voltage could easily produce different secondary voltages.


Indeed it does.

My single phase home 220 volt service runs between 245-252 volts

Pacific Greed and Extortion claims that is nominal and within spec for
home wiring.

Fortunately..most of my gear runs fine on this, with the exception of
the VFD on my Gorton mill. At times, it shows an over voltage alarm and
refuses to run until the voltage drops back down to under 246.

Ive called this to the attention of the local PG&E wanks..and they
simply shrug, send someone out to measure the voltage, confirm that
indeed its 252, blither a bit and then leave.

gunner

"Lenin called them "useful idiots," those people living in
liberal democracies who by giving moral and material support
to a totalitarian ideology in effect were braiding the rope that
would hang them. Why people who enjoyed freedom and prosperity worked
passionately to destroy both is a fascinating question, one still with us
today. Now the useful idiots can be found in the chorus of appeasement,
reflexive anti-Americanism, and sentimental idealism trying to inhibit
the necessary responses to another freedom-hating ideology, radical Islam"

Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno

On Jul 5, 11:39*am, "Geoffrey S. Mendelson"
wrote:
Doug Miller wrote:

Incorrect. Distribution voltages are on the order of a few thousand volts,
stepped down by transformers at the point of service to a few hundred. New
location = different transformer = possibly different service voltage even if
the distribution voltages are exactly the same.

Yes, BUT, a power company attempts to keep a constant voltage through their
service area. While the voltage fluctuates due to equipment, load, etc, I don't
think you can honestly say that if it is 220 volts on one side of town, the
same "grid" produces 240 on the other side of town. It might be 242 in one
place and 239 in another, but even that's a big difference unless there is
a heavy load in one location and not another.

The EU spec allowing household line voltage to be 240 volts while claiming 230
was to allow the UK to keep their current system while being "in spec" but I
doubt it was intended to allow variations from as much as 220 in one place
and 240 in another within the same country.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel *N3OWJ/4X1GM

Was going to ask someone knowledgeable to post the percentage voltage
variation allowed in the USA (or wherever it is) for 'normal service'.
For example if one were to look at European and similar so-called 230
volt systems might find that plus 10% to minus 5% (or some such thing)
quite normal? Just using those as an example that is around 218 to to
253 volts!
The question posted states "Upwards of 245 volts, whereas the machine
taps were set for 220 volts".
That is only a 12% difference! And when was the voltage found to be at
245? Immediately upon installation or several days/weeks later?
To answer the question as asked; I don't think the workman who did the
wiring is/was responsible. More so the owner who should take
responsibility for not using the proper trade/profession. If it was
say an insurance or warranty situation surely whoever has to repair or
supply the 'blown' part would ask "What tests or checks were made
after the machine was moved here and hooked up anew? There is also
nothing to say that the machine had not been working on 245 volts, or
whatever , at the old location. Also what was the agreement or
contract with the worker about testing the machines at the new
location once hooked. Maybe? Maybe not? Maybe more a task for the
people who regularly operate and service the machines regardless of
whether they are in the old or new location? Did the owner get a
cheaper job by taking the risk of using a non-registered electrician.
Two cents fom here based on what's provided!

stan wrote:

Was going to ask someone knowledgeable to post the percentage voltage
variation allowed in the USA (or wherever it is) for 'normal service'.
Average values of +5 to -10% of the nominal, in California, as
delivered at the service entrance,

jk

"Doug Miller" wrote: (clip) That said, though.... any device designed for
220V should be able to handle
245V.
^^^^^^^^^^^^^^^^^
Years ago when household appliances ran on 110 volts, we had 220. Since
then, voltage from neutral to either side rose to about 120, and voltage
across both side rose to 240. For some reason we still talk about 220 as
though it were double 120. What I'm getting at is that systems are no
longer designed for 220--it's 240, so the discrepancy is only 5 volts, and
that's trivial.

I'm guessing that the failure was due to some totally different cause, not
an error in line voltage.

On Jul 5, 4:40*pm, John E. wrote:
I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Thanks.
--
John English

Tempting as it is to blame your Mr Bush for all the eveils of the
world, including my hens not laying, I would propose the following:
1.As noted, the main supply voltage is nominal, variations are normal
and to be expected.
2.Possibly, if the machine was let stand for a while in the unpowered
position, and it was an old controller (and with a linear power
supply, it probably was,) then the electrolytics in the power supply
could have failed due high ESR, and then it lost regulation and fried
the board.
3.My humble opinion is to just mark write it off to bad luck.
Otherwise, get the lawyers involved for years and huge amounts of
money......

Andrew VK3BFA

On Jul 5, 5:04*am, Andrew VK3BFA wrote:
On Jul 5, 4:40*pm, John E. wrote:



I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Thanks.
--
John English

Tempting as it is to blame your Mr Bush for all the eveils of the
world, including my hens not laying, I would propose the following:
1.As noted, the main supply voltage is nominal, variations are normal
and to be expected.

Any reasonable design for the power supply should have defended the
controller board even if the voltage was further out of bounds than
the poster suggested.

That said: I don't think we can blame Bush for this because it didn't
burn down the whole shop in the process.

2.Possibly, if the machine was let stand for a while in the unpowered
position, and it was an old controller (and with a linear power
supply, it probably was,) then the electrolytics in the power supply
could have failed due high ESR, and then it lost regulation and fried
the board.

The capacitors could have also failed in the leaky and then exploding
manner. Having them suddenly go open as they flung their guts all
over the insides could have been the cause.

That said: I don't think we can blame Bush for this because it was
Hillary that swapped all the "N" and "Q" keys on the key boards in the
Whitehouse so it was likely her fault.

3.My humble opinion is to just mark write it off to bad luck.
Otherwise, get the lawyers involved for years and huge amounts of
money......

Andrew VK3BFA

On Jul 5, 4:40*pm, John E. wrote:
I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Thanks.
--
John English

Tempting as it is to blame your Mr Bush for all the eveils of the
world, including my hens not laying, I would propose the following:
1.As noted, the main supply voltage is nominal, variations are normal
and to be expected.
2.Possibly, if the machine was let stand for a while in the unpowered
position, and it was an old controller (and with a linear power
supply, it probably was,) then the electrolytics in the power supply
could have failed due high ESR, and then it lost regulation and fried
the board.
3.My humble opinion is to just mark write it off to bad luck.
Otherwise, get the lawyers involved for years and huge amounts of
money......

Andrew VK3BFA

In article .net, wrote:
I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Hard to make the case after 4 weeks that _anything_ the electrician did had
anything to do with this. At four seconds, or even four minutes, I'd consider
it obvious. But four weeks went by, and the owner thinks the electrician
caused this? No way.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

So what? Equipment designed for 220V should be able to handle 245V. It's not
the electrician's responsibility to open the CNC machine to see what it's set
for.

I would have two simple questions...

1. Did the electrician have any control over the voltage when the system was
rewired?

2. Is it normal for electricians to measure the voltage, and "do something"
about it if it's not correct (if only reporting the problem to the
businessman)?

William Sommerwerck wrote:

1. Did the electrician have any control over the voltage when the system was
rewired?

2. Is it normal for electricians to measure the voltage, and "do something"
about it if it's not correct (if only reporting the problem to the
businessman)?

You missed the point of the original post. The person who did the work was
NOT an electrician, they were a "handyman" hired to do the work.

Since the person never said where they were, it's hard to guess what the
rules are but in (almost?) every jurisdiction that licenses
electricians, a license is needed to do electrical work.

If an unlicensed person does electrical work, the work has to be inspected
by a licensed electrician before the power is turned on. If that was not the
case, there would be no point in licensing electricians, would there?

Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

I work on lasers that use a buck/boost with 16 tap possibilities on 3
phase all the time, and I used to use the same units in theatrical
touring service until more modern solid state lasers dominated the
laser show industry. . From that perspective, I'm amazed at the
replies here that have failed to ask two simple questions. I will
state that I never met a house electrician who ever looked at the
rating plate on the gear, although I did have a few that asked about
phase sequences.

Two, I never met a house electrician who ever checked anything
hooked to the pigtail I gave him to connect, including "professional"
rental generator technicians (actually they were the worst) In the
theatrical business, it is up to the touring operator to check the
local guys work, and in most cases, we preferred they stand in a
corner and watch us, after your first blown passbank with 3 or 4 out
of 22 power transistors blown in the laser, you get the idea to check
the taps both preshow and under load condition. In one case I asked
for 220/3, went to lunch, and came out to find 380V European power
from the generator in my distro box, which is why the box had its
own"tagged out" disconnect switch. Its a rotary switch in big modern
generators, easy to mess up.

Questions:

One, Did the "electrician" hook straight to the machine's tappable
control transformers, or did he meet a simple junction box on the
side of the machine. If it were the later, I'd say he's off the
hook. On the other hand if he was staring at a tap strip , he should
have asked. There is also the possibility of a "cascade" of
transformers in some machines, ie little CTs all over the place in the
machine, that need tapped. ??????

Two, Did anybody bother to read the manual chapter on setup? Machine
shop gear needs leveled and "trammed" when moved, its not a simple
matter of tossing a CNC off the truck onto any old pad of concrete and
expecting good parts to tolerances, and the first paragraph usually
reads, something like "check settings" and have appropriate safety
gear. ??????

The fault occurred months down the road, a instant "oof and shower
of sparks:" would point to the electrician, but months down the road
is lack of due diligence on the part of the owner.

On Jul 5, 12:34*pm, wrote:
I work on lasers that use a buck/boost with 16 tap possibilities *on 3
phase all the time, and I used to use the same units in theatrical
touring service until more modern solid state lasers dominated the
laser show industry. . *From that perspective, *I'm amazed at the
replies here that have failed to ask two simple questions. *I will
state that I never met a house electrician who ever looked at the
rating plate on the gear, although I did have a few that asked about
phase sequences.

* * Two, I never met a house electrician who ever checked anything
hooked to the pigtail I gave him to connect, including "professional"
rental generator technicians (actually they were the worst) *In the
theatrical business, it is up to the touring operator to check the
local guys work, and in most cases, we preferred they stand in a
corner and watch us, after your first blown passbank with 3 or 4 out
of 22 power *transistors blown in the laser, you get the idea to check
the taps both preshow and under load condition. * In one case I asked
for 220/3, went to lunch, *and came out to find 380V European power
from the generator *in my distro box, which is why the box had its
own"tagged out" *disconnect switch. Its a rotary switch in big modern
generators, easy to mess up.

Questions:

*One, *Did the "electrician" hook straight to the machine's tappable
control transformers, or did he meet a simple *junction box on the
side of the machine. *If it were the later, I'd say he's off the
hook. *On the other hand if he was staring at a tap strip , he should
have asked. There is also the possibility of a "cascade" of
transformers in some machines, ie little CTs all over the place in the
machine, that need tapped. ??????

Two, Did anybody bother to read the manual chapter on setup? Machine
shop gear needs leveled and "trammed" *when moved, its not a simple
matter of tossing a CNC off the truck onto any old pad of concrete and
expecting good parts to tolerances, and the first paragraph usually
reads, something like "check settings" and have appropriate safety
gear. ??????

The fault occurred months down the road, a instant *"oof and shower
of sparks:" would point to the electrician, but months down the road
is lack of due diligence on the part of the owner.

BTW just measured our North American domestic single phase here!
Leg A = 119 volts, Leg B = 121 volts. Leg A to b = 232 volts.
119/115 = 3.4% high
121/115 = 5.2% high
232/230 = 0.8% high
It's about 02.00h in mid summer so system load is probably light and
utility will have adjusted. No AC loads here; not needed.

1. Did the electrician have any control over the voltage when the system
was rewired?

2. Is it normal for electricians to measure the voltage, and "do
something"
about it if it's not correct (if only reporting the problem to the
businessman)?

You missed the point of the original post. The person who did the work was
NOT an electrician, they were a "handyman" hired to do the work.

I didn't miss the point (I think). He was doing the work of an electrician.
And whether or not he was a licensed electrician, he is still morally
responsible for the quality of his work. (Think Hamurabi.)


Since the person never said where they were, it's hard to guess what the
rules are but in (almost?) every jurisdiction that licenses
electricians, a license is needed to do electrical work.

If an unlicensed person does electrical work, the work has to be inspected
by a licensed electrician before the power is turned on. If that was not
the
case, there would be no point in licensing electricians, would there?

No, there wouldn't be. But if he botched the job, he has to be held
responsible. Doesn't he?

Of course, one might argue that if the person who hired him /knew/ he wasn't
an electrician, and didn't have the work inspected, then he (the hirer) is
responsible for whatever went wrong.

In article , "William Sommerwerck" wrote:
1. Did the electrician have any control over the voltage when the system
was rewired?

2. Is it normal for electricians to measure the voltage, and "do
something"
about it if it's not correct (if only reporting the problem to the
businessman)?

You missed the point of the original post. The person who did the work was
NOT an electrician, they were a "handyman" hired to do the work.

I didn't miss the point (I think). He was doing the work of an electrician.
And whether or not he was a licensed electrician, he is still morally
responsible for the quality of his work. (Think Hamurabi.)

Actually, you *are* missing the important point, which is that it's
_not_his_fault_:

1) 245VAC is *not* a problem in a nominal 240VAC supply.
2) If the equipment is actually labelled 220V, and not 240V, it's *old*.
3) Equipment designed for 220VAC normally operates just fine on 240VAC.
4) If the wiring, or the voltage, were in any way to blame, the failure almost
certainly would have occurred long before it did. Four weeks after the fact, I
can't see how that could be laid at the feet of the guy that did the wiring,
licensed or not.