Are PC surge protectors needed in the UK?

[w_tom]

Transmitted an incomplete post. Sorry for the mistake.
Now for that airplane. Notice earth ground is the tail
section:
http://bm6aak.myweb.hinet.net/file/456.gif

Of course this airplane ground is completely beyond the
scope of the current discussion. Airplanes are more difficult
to ground. A Pan Am 707 was destroyed by lightning over
Elkland MD because internal grounding was not sufficient. An
airplane must be grounded so that any part can become an earth
ground; making airplane design more challenging. We, on the
other hand, are having enough trouble discussing simple
structural earthing - a well proven 1930 technology. Why then
complicate it with airplanes and other irerelevant questions?

 

[Ron Reaugh]

Ok sir. Explain to us how a plug-in UPS provides common mode
protection. Also cite the manufactuer's spec that claims that
common mode protection (and good luck).

No problem. Here:
http://sturgeon.apcc.com/techref.nsf/partnum/990-7015/$FILE/7015-1.pdf
Section 9.4

Do you understand what common mode means with respect to the above spec and
do you understand how that differs/same as the general concept of common
mode and how that relates to these issues?

In order to protect a device from an undesirable voltage arriving over the
power cable one simply shunts that unwanted voltage such that it appears
equally on all the wires on that power cable i.e. AC-hot, AC-neutral and
the ground wire which connects to the chassis of the device. That shunt is
done with capacitors and surge diodes or MOV devices etc. or in the old days
on your phone line with a spark gap. That's basically what a surge
suppressor does. The device's input components therefore see no intolerable
VOLTAGES and it survives. It makes no difference to the device if the whole
device(chassis and all) jumps to a million volts during the episode. Ever
heard of a Faraday Cage?

Also please explain how those 130 ohms impedance in 50' of
12 AWG wire is not significant when earthing even a trivial
100 amp surge?

Not relevant. What happens on an airplane? The protection issue isn't
grounding a surge current; the issue is maintaining important components at
a stable/safe voltage with respect to one another such that nothing gets
damaged. Ever heard of a Faraday Cage?

In the meantime, please explain how earth ground at a hydro
electric plant is at all related to single point earth ground
for a building,

In large buildings as in hydroelectric plants there is NO SINGLE POINT
ground but multiple connections to a common ground cage/plane. On an
airplane there isn't even one point to ground except an ionized air column t
hat chooses its own path for a few microseconds at a time on occasion.
Ever heard of the concept of a ground plane? Every heard on the concept of
capacitive coupling and AC impedance? How does a Faraday Cage relate to a
ground plane?

for a PA or stereo system, for the PC board
layout of A/D converters, or any other simple electronic
system where ground loops can be a problem. You do understand
the concept of ground loop?

You're walkin into my backyard now. Now what's the difference in design of
that DA for 8 bit 800MHz conversion and 24 bit 200KHz conversion? DAs are
more fun that ADs.

Good. Please then show us how
the ground at a power station has any relevance?

Now for the completely irrelevant topic of ground in an
airplane:

It's entirely relevant to demonstrating that you have no understanding of
the issues in question.

The answer is that the principles of how to do system input protection on an
airplane are IDENTICAL to how to do them at home or in a high rise.

The NUMBER ONE FAILURE of an incompetent designer in this arena is to
mistake that a ground connection has much to do with the issue; it does
NOT. The ground connection has much more to do with other issues like the
safety of the guy who is using the box and the UL and the national
electrical code. Why do you suppose that US home wiring didn't even include
a 3rd wire(ground) until the 50's? Do you think some new physical law was
suddenly discovered?

One can protect a gadget from surges WITHOUT a ground wire or any ground at
all; that's the WHOLE point. Shunt the surge voltage such that it's common
moded and to the chassis at the input and outputs and the device is
protected.

 

[Ron Reaugh]

Transmitted an incomplete post. Sorry for the mistake.
Now for that airplane. Notice earth ground is the tail
section:
http://bm6aak.myweb.hinet.net/file/456.gif

OH, cool but of course it simply proves my points.

Of course this airplane ground is completely beyond the
scope of the current discussion.

You mean beyond you.

Airplanes are more difficult
to ground.

No, airplanes are impossible to proactively ground while in flight(save a
high energy beam) and much more importantly the is no need to ground an
airplane in flight. There is just a need to have a good continuous Faraday
Cage. Damn, how did anyone ever survive when planes were made of wood or
paper(or are they non-conductors)?

A Pan Am 707 was destroyed by lightning over
Elkland MD because internal grounding was not sufficient.

Oh, you mean the Faraday Cage was discontinuous or flawed or maybe it was a
super bolt of the kind that has punched holes in heavy gauge steel petroleum
tanks.
In any case I'll bet that the cockpit radio was undamaged at least until
impact.

An
airplane must be grounded so that any part can become an earth
ground; making airplane design more challenging.
HUH?

We, on the
other hand, are having enough trouble discussing simple
structural earthing - a well proven 1930 technology. Why then
complicate it with airplanes and other irerelevant questions?

Because device/PC protection design has little to do with earth grounding.

 

[Ron Reaugh]

Was UPS between AC mains and computer? No.

Wrong. Topologically the UPS is "between".

UPS and
computer both connect to AC mains just like light bulbs. In
fact it would be same protection if both computer and UPS
shared same wall receptacle.

WRONG! About a critical 10 nanoseconds WRONG nevermind the impedances and
common mode condiderations!

Any transient from the
receptacle confronts UPS and computer equally.

Not in the critical time domain.

However
protection inside a UPS is often so grossly undersized that a
surge too small to damage a computer might still damage the
UPS. Furthermore, some computers can even act as surge
protectors - shunt a destructive surge so that it does not
seek earth ground via other computers.

Until you define specific circuits - including how every
wall receptacle is wired, then I cannot provide more
information.

I cannot say exactly why that particular event happened.
But above is one reason why a UPS may be damaged and computer
is not.

NO, the first component with surge suppression topologically is usually the
one that takes the HIT. Do you suppose that's by design?

Computer power supplies have internal protection.
Protection so sufficient that there is little adjacent to a
power supply that can enhance protection. But computer
internal protection can be overwhelmed if destructive
transients are not earthed before entering the building.

OH, you mean unless the building is a heavily constructed Faraday cage and
all wiring has feedthru bypass and surge suppression, then a destructive
transient could get through and that has NOTHING to do with you high
transient impedance ground wire.. Why is it that we all knew that?

Bottom line is this. You had UPS failure. Therefore you
have no effective surge protection. Even surge protectors
must not be damaged due to a surge.

HUH, frequently good surge protectors are destroyed by big surges just as
they are designed to do. The good one FAIL closed circuit where protection
is even better!

To provide a better answer, do as I do - autopsy the dead
body. Replace the defective part to learn what has actually
been damaged. Autopsy only complete when the failed unit is
fully functional.

If a server farm has no 'whole house' protection and a single
point earth ground,

NO, a large server farm has grid ground and power grid firewalls.

then no UPS or plug-in protector is going
to do anything better. In fact, it is just not a reliable
operation if 1) every incoming utility line does not enter at
the common service entrance all connected to the single point
earth ground

No, you are getting closer to reality.

and 2) building does not have necessary 'whole
house' protector on incoming AC mains. From Sun Microsystems
planning guide:
http://www.sun.com/servers/white-papers/dc-planning-guide.pdf

To a good Faraday cage or ground plane. A circuit of LOW AC IMPEDANCE.

What that all boils down to is design the Faraday Cage or ground plane well
and has little to do with actual earth grounding save the UL and electrical
code.

 

[Chaos Master]

J.J. said:

Does anyone have a reference to HDDs getting corrupted by power
events on the mains power supply?

Happened here. Power surge, while I was working on a MS-Word document.

Returned, Windows booted, but crashed at the desktop, so I entered using a Win98
boot disk and ran Scandisk.

2 or 3 bad blocks, and some files/Windows' registry were corrupted.

[]s

 

[w_tom]

Please feel free to show us an MOV datasheet that says

... good surge protectors are destroyed by big surges just
as they are designed to do. The good one FAIL closed
circuit where protection is even better!

That claim is classic urban myth. MOV data sheets define
normal operation. MOV is at end of life typically when it
degrades by about 5%. How can it degrade 5% and yet
vaporize? It cannot. Bottom line remains - a properly sized
protector shunts the transient and remains fully operational.
Eventually MOV degrades; does not vaporize. Vaporizing is
when the MOV grossly exceeds manufacturer specification - is
grossly undersized for the task. But purveyors of undersized
and ineffective protectors want consumers to believe their
overpriced protector should vaporize on every surge. Scam is
the better word.

In the meantime, there is no topology in electronic
circuits. Electrically, a shunt mode protector is not
"between" the appliance and a surge no matter how much junk
science topology is rationalized. But then this thread is
full of myth purveyors promoting such junk science reasoning -
such as MOVs are designed to protect by vaporizing. Which
plug-in manufacturer do you work for, Ron Reaugh?

 

[w_tom]

Well lets see. The Boeing 707 was an entire 'faraday cage'
of aluminum. And inside that aluminum 'faraday cage' was a
completely enclosed fuel tank - another faraday cage. How did
lightning get through two faraday cages to explode the fuel
tank on that Boeing 707? And why was the correction to
install more grounds inside that 'faraday cage'? Could it be
that no sufficient 'faraday cage' exists? Yep.

Ron, when you get some real world experience with 'faraday
cages', then come back and share your experiences. In the
meantime, grounding inside that 'faraday cage' is essential
for safe airline operations - so that lightning will pass
through the inside of that 'faraday cage' without doing
damage. Lightning caused damage inside that 'faraday cage'
over Elkton MD.

 

[w_tom]

Ron. Did you read your citation before posting it? Where
is the reference to common mode protection? Where are any
numbers that apply to common mode protection? Once APC used
to provide far more numbers when they claimed to protect from
Normal mode transients. Now they don't even make those
claims. Numbers provided by Ron's citation:

Surge energy rating (one time, 10/1000 µs
waveform): 160 J.
Surge current capability (one time, 8/20 µs
waveform): 6500 Amp peak maximum.

Hell. They don't even list dBs for the noise filter. What
kind of spec is that? Noise filter for what? Incoming AC
line? Output power line? Clearly these are specs for the
technically naive.

After one surge, the entire UPS is toast? Look at those
pathetic numbers. Only 160 joules? Only 6500 amps?
Effective protection starts at about 1000 joules and 50,000
amps. Thank you Ron for demonstrating pathetic protection
from that plug-in UPS.

Oh - where do they mention anything about 'faraday cage'
protection?

In the meantime, Ron describes normal mode protection:

In order to protect a device from an undesirable voltage
arriving over the power cable one simply shunts that unwanted
voltage such that it appears equally on all the wires on that
power cable ...

Where is the common mode protection? Not in that citation.
Not in what Ron describes. Just another reason why that
plug-in UPS does not provide effective protection.

 

[w_tom]

View specs for a plug-in protector. It claims to protect
from a type of surge that does not typically exist. That way,
the myth purveyors will assume it protects from all types of
surges. And so we have a common quote - "a surge got past my
surge protector". In reality, the surge took a left turn to
get the surge protector and a right turn to attack the
computer - simultaneously.

Get a surge protector that protects from a type of surge
that actually does damage. So which one do you install? The
one that costs tens of times more money per protected
appliance, OR the one that costs so much less and even
protects from the destructive type of surge? The latter is
the single, properly sized, and properly earthed 'whole house'
protector. Now that the best protector is also the most cost
effective, we can compare that price to what we might lose
without installing it. IOW the 'whole house' protector
provides a basis to decide protection for everything inside
the house.

Is a PC surge protector needed in the UK. No: if protectors
is the ineffective plug-in type that may even contribute to
damage of an adjacent computer. Maybe: if it is the less
expensive and more effective 'whole house' type.

 

[w_tom]

Why is 'absorb' verse 'shunt' an important difference? If a
protector absorbs surges, then it sits between surge and the
protected device - in series. It must stop or block surges.
But then it must be a series mode protector. It is not. It
is shunt mode. Shunt mode protectors don't function if they
absorb surge energy. Difference between 'shunt' and 'absorb'
is important to keep the consumer confused.

A shunt mode protector connects off to the side; is not
located electrically between protected device and incoming
transient. A shunt mode protector connects as if it was
another appliance - albeit much closer to the single point
ground.

Absorbing is what the plug-in protector manufacturer hopes
you assume. That way they need not discuss earthing and hope
you assume it is a series mode protector. But they are,
instead, shunt mode protectors. Effective shunt mode
protectors must be connected short to earth ground. If you
*assume* it absorbs surges then they can avoid an earthing
discussion; let myths purveyors promote their ineffective
product.

Series mode protectors absorb. Shunt mode protectors are
similar to electric switches or electric wires - they shunt.
If others believe that it absorbs, then critical earth ground
may be overlooked. Essential to selling that ineffective
protector is to avoid all mention of earthing. And so they
hope other will *assume* it absorbs. If it shunts, then one
may ask what it shunts to? Those would be embarrassing
questions.

 

[Ron Reaugh]

Please feel free to show us an MOV datasheet that says

That claim is classic urban myth. MOV data sheets define
normal operation. MOV is at end of life typically when it
degrades by about 5%. How can it degrade 5% and yet
vaporize? It cannot. Bottom line remains - a properly sized
protector shunts the transient and remains fully operational.
Eventually MOV degrades; does not vaporize. Vaporizing is
when the MOV grossly exceeds manufacturer specification - is
grossly undersized for the task. But purveyors of undersized
and ineffective protectors want consumers to believe their
overpriced protector should vaporize on every surge. Scam is
the better word.

Gibber ignored.

In the meantime, there is no topology in electronic
circuits.

And this wacko nonsense is from the guy who brought up DA design! At high
frequency it is most ALL about topology!

Electrically, a shunt mode protector is not
"between" the appliance and a surge no matter how much junk
science topology is rationalized.

Did you ever hear about the speed of light or about 1 foot per nanosecond?

But then this thread is
full of myth purveyors promoting such junk science reasoning -
such as MOVs are designed to protect by vaporizing. Which
plug-in manufacturer do you work for, Ron Reaugh?

Vaporizing...are you gonna bring in Klingons now as we seem to be having a
bit to drink?

 

[Ron Reaugh]

Ron. Did you read your citation before posting it? Where
is the reference to common mode protection?

Right where I said it was as anyone who reads it can see for themselves.
Gain some technical background before you tackle such technical issues.

 

[Ron Reaugh]

Well lets see. The Boeing 707 was an entire 'faraday cage'
of aluminum. And inside that aluminum 'faraday cage' was a
completely enclosed fuel tank - another faraday cage. How did
lightning get through two faraday cages to explode the fuel
tank on that Boeing 707? And why was the correction to
install more grounds inside that 'faraday cage'? Could it be
that no sufficient 'faraday cage' exists? Yep.

If you'd read my previous post I already said exactly that.

Ron, when you get some real world experience with 'faraday
cages', then come back and share your experiences. In the
meantime, grounding inside that 'faraday cage' is essential
for safe airline operations - so that lightning will pass
through the inside of that 'faraday cage' without doing
damage. Lightning caused damage inside that 'faraday cage'
over Elkton MD.

No, inside a discontinuous Faraday cage....get a clue.

 

[w_tom]

Put an impulse down a wire. Where on that wire will the
impulse voltage first be seen? On the near end where the
impulse starts? Obviously not. Impulse first appears at the
far end of wire. How can this be when it takes the impulse 1
foot per second to get to that far end? Topology as defined
by Ron would erroneously conclude impulse first appears where
impulse was first applied to wire.

Why do we know that topology not relevant? Its a simple
second year course called E-M fields. One first learned basic
concepts before promoting rubbish such as topology and
'faraday cage'.

Notice that Ron Reugh also cannot provide MOV datasheets to
demonstrate protection by vaporization. He is typical of
those who would recommend plug-in protectors. Facts remain
unchallenged: a surge protector that vaporizes during a surge
is ineffective and even violates the MOV manufacturer's own
specifications. Ron's best technical response:

 

[w_tom]

IOW there is no claim in that APC sales brochure for common
mode transient protection. Even worse, they no longer make the
specific claim for normal mode protection. Ron again
demonstrates propaganda used to promote plug-in UPSes for
ineffective surge protection.

 

[J.J.]

A 3 or 5% reduction in voltage, also known as a brownout to
the utility, is totally irrelevant to electronics and
especially irrelevant to computers. A computer works just
fine even when incandescent bulbs dim to less than 40%
intensity. Even demanded in Intel specifications. IOW what
the utility calls a voltage reduction is full power to the
computer. Utility would have to decrease voltage more than
20% for a computer to see a brownout. But if utility voltage
drops that low, then electric motors may be damaged. IOW
voltage too low to damage electric motors is even full power
to a computer - which demonstrates how resilient a computer
really is.

BTW, utility does not institute a voltage reduction to save
money. Voltage reductions are a last ditch effort to avoid
rolling blackouts.

Spikes and harmonics are (or should be) irrelevant to a
computer. Again, because the computer is so resilient.
However that internal computer protection assumes the building
has a 'whole house' protector so that spikes cannot overwhelm
computer internal protection.

All of which is irrelevant to HD protection. Either the
power supply will output correct power or it will shutdown.
This, of course, assumes the computer assembler had basic
electrical knowledge and did not install those 'defective by
design' $25 or $40 power supplies. But again, this was
explained earlier.

If a computer PSU fails then I have heard that it may (or may not)
blow the mainboard and perhaps various other components with a
power surge or soemthing like that.

It seems that better PSUs are designed so that when they fail they
have some circuitry which protects the other components in the PC.

Is this failsafe feature of the PSU I am referring to pretty much
the same feature you are referring to? Or are they separate
features?

Does anyone know how common it is to get this failsafe feature in a
PSU?

 

[John Gilmer]

Just another reason why FAT was obsoleted by HPFS which in
turn was obsoleted by NTFS.

I'l bite:

I think I understant FAT systems.

But the only thing I "think" I know about the NTFS is that, effectively, the
system first makes a record of what it is about to do, then it does it, and
then it either erases the original record or somehow marks it.

SO: can someone "explain" the NTFS to me. (Please don't tell me to "look
it up.")

 

[Mike]

Does anyone have a reference to HDDs getting corrupted by power
events on the mains power supply?

Reference Microsoft

"Because you didn't shut down Windows properly, Scandisk is now trashing
your disk to complete the job.

In future, always shut down Windows properly"

Scandisk is not *always* going to pull your nuts out of the fire after a
power interruption. In fact, it might make things worse

Wouldn't you *expect* data corruption, if the system was writing/about to
write cached data, and the mains power went off?

You don't need references to figure out that it's a bad idea to just
lose power in an uncontrolled way.

 

[The Ghost In The Machine]

In sci.physics, w_tom
<[email protected]>
wrote

Put an impulse down a wire. Where on that wire will the
impulse voltage first be seen? On the near end where the
impulse starts? Obviously not. Impulse first appears at the
far end of wire. How can this be when it takes the impulse 1
foot per second to get to that far end?

Erm, 1 foot per *nano*second. Light speed.

Perhaps it's somewhat less than that; AIUI electric current
is along the lines of 2/3 c, but it's still pretty darned
fast.

[rest snipped]

 

[Ron Reaugh]

Put an impulse down a wire.

You can't even define "impulse".

Where on that wire will the
impulse voltage first be seen? On the near end where the
impulse starts? Obviously not. Impulse first appears at the
far end of wire.

Now you've self contradicted and imploded. Ask Albert.