Lem wrote in message
...
Are surge protectors on the main power supply actually needed in
the UK?

here in the UK we have few overhead mains power lines and have a
relatively steady mains power supply when compared to many other
countries (including the US).

However there seem to be very many surge protector products
advertised for sale in the UK (Argos, Maplins, etc).

I am quite sure it is not bad practice to use a surge protector but
in fact I have never known anyone who has has a problem from a
surge coming in through the power supply.

So personally I don't bother using a surge protector on my PC.

Am I being too complacent?

It all depends on your tolerance of risk.

It doesn't have to hit a power pole. A friend of mine lost 2 PCs when
lightning hit a tree next to her house, then jumped to the house (knocking
some siding off in the process).

Surge protectors are cheap. Or just back up your data regularly.

--
greywolf42
ubi dubium ibi libertas
{remove planet for return e-mail}

In article ,
Lem writes:
Are surge protectors on the main power supply actually needed in
the UK?

No, at least not to protect PCs.

here in the UK we have few overhead mains power lines and have a
relatively steady mains power supply when compared to many other
countries (including the US).

However there seem to be very many surge protector products
advertised for sale in the UK (Argos, Maplins, etc).

Lots of people run a particular OS which is known for its
instability, and you can sell them just about anything if
you suggest it might make their systems more stable. Of
course it doesn't, but that just means they'll try something
else (except changing the OS;-). Surge protectors are one of
the many items on the list that such people will try.

The other issue is that the multi-way trailing socket blocks
got down to the point where they're only a couple of pounds
each, or even less. By adding a extra few pence worth of
components, you can call them surge protected and sell them
for 3 times the price. Brings in more profit.

I am quite sure it is not bad practice to use a surge protector but
in fact I have never known anyone who has has a problem from a
surge coming in through the power supply.

True. Even if you have millions of pounds worth of equipment
on your supply, it isn't worth it, the occurance is so rare,
so it certainly isn't for a few home PC's.

What I have seen several times is damage caused by a surge
induced by lightning on a phone line. Of course, the mains
surge protector will do nothing to protect against that.

So personally I don't bother using a surge protector on my PC.

Am I being too complacent?

Not in my opinion.
If I saw something at less than rip-off prices for protecting
against surge on phone line, I might consider that.

--
Andrew Gabriel

Is the cumulative effect of transient voltages leading to premature
equipment failure not an issue then?
something as simple as a desk fan switched on & off and supplied via the
same socket as a PC can create a transient over voltage of 1kV
Sure it will not knock the PC out but it will reduce the life of the kit.






"Andrew Gabriel" wrote in message
...
In article ,
Lem writes:
Are surge protectors on the main power supply actually needed in
the UK?

No, at least not to protect PCs.

here in the UK we have few overhead mains power lines and have a
relatively steady mains power supply when compared to many other
countries (including the US).

However there seem to be very many surge protector products
advertised for sale in the UK (Argos, Maplins, etc).

Lots of people run a particular OS which is known for its
instability, and you can sell them just about anything if
you suggest it might make their systems more stable. Of
course it doesn't, but that just means they'll try something
else (except changing the OS;-). Surge protectors are one of
the many items on the list that such people will try.

The other issue is that the multi-way trailing socket blocks
got down to the point where they're only a couple of pounds
each, or even less. By adding a extra few pence worth of
components, you can call them surge protected and sell them
for 3 times the price. Brings in more profit.

I am quite sure it is not bad practice to use a surge protector but
in fact I have never known anyone who has has a problem from a
surge coming in through the power supply.

True. Even if you have millions of pounds worth of equipment
on your supply, it isn't worth it, the occurance is so rare,
so it certainly isn't for a few home PC's.

What I have seen several times is damage caused by a surge
induced by lightning on a phone line. Of course, the mains
surge protector will do nothing to protect against that.

So personally I don't bother using a surge protector on my PC.

Am I being too complacent?

Not in my opinion.
If I saw something at less than rip-off prices for protecting
against surge on phone line, I might consider that.

--
Andrew Gabriel

"Lem" wrote in message
...
Are surge protectors on the main power supply actually needed in
the UK?

here in the UK we have few overhead mains power lines and have a
relatively steady mains power supply when compared to many other
countries (including the US).

However there seem to be very many surge protector products
advertised for sale in the UK (Argos, Maplins, etc).

I am quite sure it is not bad practice to use a surge protector but
in fact I have never known anyone who has has a problem from a
surge coming in through the power supply.

So personally I don't bother using a surge protector on my PC.

Am I being too complacent?


I have no UK electrical power system knowledge.

I do however have extensive electrical utility knowledge.

I would never install a computer without a UPS.

What is the age of the installed cables? When a cable faults the surge is
substantial.
Transformers, capacitors, breakers, generators ...all fault at times and
they result in heavy electrical surges.

HDD are frequently corrupted due to power events.

~$40 USD (350VA) with $15000 of equipment insurance is worthwhile.

greywolf42 wrote:
It doesn't have to hit a power pole. A friend of mine lost 2 PCs when
lightning hit a tree next to her house, then jumped to the house (knocking
some siding off in the process).
The tree ? Lost or not ?

Soren

"J.J." wrote in :



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



References, no, practical, hands on experience, yes. I've seen this
several times, not only the HDD, but I've had transient power problems
take out motherboards too.
Examples:
Case 1: Home computer (this one) tree fell across a main line (11kva I
think), caused a surge prior to the stepdown transformer kicking out,
corrupted an almost new 40 gig hdd. Fortunately, an LLF fixed it.
Case 2: Engraving lasers at work, fed from the bus, kept killing HDD's
and motherboards. Ultimately traced to transient voltage spikes,
installed an AVR UPS. Failures were occuring once to twice a week, after
the AVR UPS was installed on each machine, we have had Zero failures, in
over a year.



--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

Remove sp to reply via email

Andrew Gabriel wrote:
What I have seen several times is damage caused by a surge
induced by lightning on a phone line. Of course, the mains
surge protector will do nothing to protect against that.

So personally I don't bother using a surge protector on my PC.

Am I being too complacent?

Not in my opinion.
If I saw something at less than rip-off prices for protecting
against surge on phone line, I might consider that.

I have a surge protector which includes protection for the phone line,
so that's where the ADSL modem gets plugged. Whether it would actually
work or not is another matter of course. My complacency lies in not
bothering to research the matter thoroughly, on the grounds that if I
was buying snake oil, it was at least *cheap* snake oil...

For the mains, online UPS is the proper solution, but I can't say I'm
unduly concerned about not having one. Power provision in the UK is
fairly reliable at the moment, although political and business
imperatives will probably conspire to make it worse in the future.

A plug-in surge protector is on the order of tens of times
more money per protected appliance. Furthermore it does not
even claim to protect from the typically destructive
transient. Protectors do not stop, block, filter, or absorb
destructive transients. Ineffective protector manufacturers
get one to wish that is how they work. In reality, the
protector is not protection. Protector and protection are two
separate components of a surge protection system. Effective
systems must include the protection. And the connection to
protection is either a hardwire (less than 3 meters) or a
protector (also part of a less than 3 meter connection).

In short, the protection is called single point earth
ground. Destructive surges may enter the building seeking
earth ground. If not earthed (either by hardwire connection
or by surge protector), then the destructive surge may find a
path to earth ground via computer. One classic example is due
to a direct strike to lines highest on utility poles - AC
electric. Incoming on AC electric, through computer and its
modem, then outgoing to earth ground via phone line. Many
then *assume* the surge entered on phone line, damaged modem,
then stopped - a violation of even primary school science.

Effective protection means all incoming utilities are
earthed before entering the building. All must be earthed to
the same single point earth ground. That means even the CATV
wire drops down to earth ground, connects ground block 'less
than 3 meters' to that earth ground, and only then rises back
up to enter building. Again, no surge protector required
because earthing is accomplished by a direct and short
hardwire connection.

These concepts are explained further including some examples
of 'whole house' protectors for AC mains at:
"RJ-11 line protection?" on 30 Dec 2003 through 12 Jan 2004 in
pdx.computing at
http://tinyurl.com/2hl53 and
"strange problem after power surge/thunderstorm" in
comp.dcom.modems on 31 Mar 2003 at
http://tinyurl.com/2gumt .

Additional information on how surge protectors work, how
they are rated, installed, etc was posted in:
"Opinions on Surge Protectors?" on 7 Jul 2003 in the
newsgroup alt.certification.a-plus at
http://tinyurl.com/l3m9 and
"Power Surge" on 29 Sept 2003 in the newsgroup
alt.comp.hardware at
http://tinyurl.com/p1rk

One industry professional demonstrates how two structures
are protected. Notice every wire entering each structure
(building and tower) must first connect to single point
ground. Even the buried phone wire carries a potentially
destructive transient which is why even buried wires must
enter building at the service entrance with the 'less than 3
meter' connection to earth ground:

http://www.erico.com/public/library/...es/tncr002.pdf

How do we identify ineffective protectors? 1) No dedicated
connection to earth ground AND 2) manufacturer avoids all
discussion about earthing. A surge protector is only as
effective as its earth ground - the protection.

Those ineffective protector manufacturers fear you might
learn about the essential earth ground AND discover that
plug-in protectors cost tens of times more money per protected
appliance.

Pyriform wrote:
I have a surge protector which includes protection for the
phone line, so that's where the ADSL modem gets plugged.
Whether it would actually work or not is another matter of
course. My complacency lies in not bothering to research the
matter thoroughly, on the grounds that if I was buying snake
oil, it was at least *cheap* snake oil...

For the mains, online UPS is the proper solution, but I
can't say I'm unduly concerned about not having one. Power
provision in the UK is fairly reliable at the moment,
although political and business imperatives will probably
conspire to make it worse in the future.

Hard drives can be corrupted for various reasons based also
upon what the filesystem is. For example, if using FATxx
filesystems, then a loss of electrical power at the right time
can even erase files from that drive. Just another reason why
the technically informed want NTFS filesystems on drives; not
FAT.

Transients should never be a problem to disk drives or
memory. Based upon how these devices are connected, then a
differential type transient would be required to cause
damage. But all minimally acceptable power supplies must have
the essential function called overvoltage protection - that
makes a differential transient not possible.

That is the theory as well proven by power supplies even 30
years ago. Reality is the gross profits obtained by dumping
inferior supplies in North America where so many computer
assemblers don't even have basic electrical knowledge. Many
clones are not built and sold missing the essential
overvoltage protection because the assembler only understands
one specification - dollars. It's called a bean counter
mentality. If the power supply is sold on the cheap, (ie full
retail price is less than $60), then this and other critical
functions are simply *forgotten*. Does not matter. Consumer
is only to be fleeced.

If the destructive differential transient does occur, there
is no overvoltage protection circuit to protect that hardware
- do to power supply purchased by a bean counter. No
problem. Myth purveyors then quickly blame speculated surges,
and recommend overpriced, typically undersized, and
ineffective plug-in protectors.

Up front - does the power supply specifically state that
overvoltage protection is provided? If not, then it probably
is a man-made disaster just waiting to destroy disk drive,
data, and other computer components.

This overvoltage protection is something completely
different from another disk drive threat to FAT filesystems -
blackouts and brownouts.

"J.J." wrote:
Does anyone have a reference to HDDs getting corrupted by
power events on the mains power supply?

Again an assumption that something will stop or block a
destructive transient. Kilometers of air could not stop the
transient. Do you think that silly little RCD switch contact
will do what kilometers of sky could not? Again, protection
is about shunting (diverting, connecting, shorting) a
transient to earth ground. There is no way around that
fundamental fact. Nothing is effective at stopping such
transients.

Again, read those cited discussions. Effective protection
was even demonstrated by Ben Franklin in 1752. It too is
discussed there. Did Franklin stop or block transients? Of
course not. Only products selling on myths attempt to get
others to "speculate" that protectors work by sitting between
the transient and its objective - earth ground destructively
via a computer.

Second - what fast acting switch? That RCD maybe takes 10
milliseconds to respond. In the meantime, 300 consecutive and
destructive transient would complete before the RCD even
thought about tripping. That fast acting switch has the speed
of molasses. Effective protection is defined in those
previously cited posts. You have much to learn there.

"J.J." wrote:
Could a very fast-acting switch (like in an Residual Current
Detector) be used to cut the incoming power supply quickly enough
to halt the transient mains electricity spike before it got to be
too large?

In article ,
"Pyriform" writes:
For the mains, online UPS is the proper solution, but I can't say I'm
unduly concerned about not having one. Power provision in the UK is
fairly reliable at the moment, although political and business
imperatives will probably conspire to make it worse in the future.

Yes, we've had an exceptionally stable/reliable supply in the UK
for perhaps 30 years now (or well over 40 years if you ignore the
1972 miners strike). There are a number of reasons why that's
unlikely to be maintained in the future though.

--
Andrew Gabriel

In article , w_tom wrote:
Again an assumption that something will stop or block a
destructive transient. Kilometers of air could not stop the
transient. Do you think that silly little RCD switch contact
will do what kilometers of sky could not? Again, protection
is about shunting (diverting, connecting, shorting) a
transient to earth ground. There is no way around that
fundamental fact. Nothing is effective at stopping such
transients.

My surge protector came with a guarantee that the company will pay to
repair or replace any equipment damaged through the powerlines when it was
plugged in to their product.
--
"Outside the camp you shall have a place set aside to be used as a
latrine. You shall keep a trowel in your equipment and with it, when you
go outside to ease nature, you shall first dig a hole and afterward cover
up your excrement." -- Deuteronomy 23:13-14

"Gregory L. Hansen" wrote in message
...
In article , w_tom
wrote:
Again an assumption that something will stop or block a
destructive transient. Kilometers of air could not stop the
transient. Do you think that silly little RCD switch contact
will do what kilometers of sky could not? Again, protection
is about shunting (diverting, connecting, shorting) a
transient to earth ground. There is no way around that
fundamental fact. Nothing is effective at stopping such
transients.

My surge protector came with a guarantee that the company will pay to
repair or replace any equipment damaged through the powerlines when it was
plugged in to their product.
--

I've been around for some time now, and I've never known or heard of anyone
actually collecting on such an offer. I know a few that tried, but gave up
after about the fifteenth hoop (getting through the first few was a cake
walk, but they kept getting higher, and higher!). :-] I've heard that
some outfits will pay claims depending on the cost of the item involved, but
know damage will occur with their devices, and consider the payout a cost of
doing business.

Read all the fine print on the offer you have, and report back if you think
you still have a prayer collecting after damaging surge event.

Louis--
*********************************************
Remove the two fish in address to respond

On Fri, 09 Jul 2004 02:16:23 +0000, Gregory L. Hansen wrote:

In article , w_tom wrote:
Again an assumption that something will stop or block a
destructive transient. Kilometers of air could not stop the
transient. Do you think that silly little RCD switch contact
will do what kilometers of sky could not? Again, protection
is about shunting (diverting, connecting, shorting) a
transient to earth ground. There is no way around that
fundamental fact. Nothing is effective at stopping such
transients.

My surge protector came with a guarantee that the company will pay to
repair or replace any equipment damaged through the powerlines when it was
plugged in to their product.

Have you collected on that promise? Somehow I think you'd buy an extended
warranty on that strip too. ;-)

--
Keith

In article ,
"J.J." writes:
(Andrew Gabriel) wrote:

Yes, we've had an exceptionally stable/reliable supply in the
UK for perhaps 30 years now (or well over 40 years if you
ignore the 1972 miners strike). There are a number of reasons
why that's unlikely to be maintained in the future though.

What sort of reasons do you have in mind for causing a less
stable/reliable UK mains power supply?

In a nutshell...
o We are no longer self-sufficient in energy (became a natural gas
importer last year) and are increasingly going to have to rely on
sources from the less stable parts of the planet and sources
which require traversing the less stable parts of the planet.
o All the non-natural gas sources of generation are winding down
at the end of their service lifetimes, and no more being built
(ignoring renewables, which are currently insignificant).
o We no longer have a store of energy -- we used to have many months
supply of coal stockpiled at power stations and weeks supply of
gas stored in gasometers -- all now gone.
o We now have very little in the way of spare generating capacity.
The nationalised electricity generating board used to maintain
spare capacity to enable peaks and unexpected outages to be
handled without concern, but the privatised companies mothballed
this plant as they are only paid for what they produce. It
would take between 3 months and a year to get it back in service,
depending how long it's been mothballed, so it's no use as an
energency reserve.

The industry had a wake-up call on 10 December 2002 when the country
got within a couple of minutes of having to load shed (switch off
parts of the country in an emergency due to not enough power being
able to be generated to meet demand). In spite of this, nothing was
done. Again last winter, there was a particularly cold spell forecast
and a number of experts warned we were in an even worse state than
the year before. Fortunately, the cold spell wasn't anything like as
bad as forecast. Given these wake-up calls have been ignored by the
government, it looks like it's going to have to get worse before
any notice is taken, and we probably are going to have to suffer a
significant load-shedding incident blacking out significant parts of
the country.

--
Andrew Gabriel

In article ,
(Gregory L. Hansen) writes:

My surge protector came with a guarantee that the company will pay to
repair or replace any equipment damaged through the powerlines when it was
plugged in to their product.

If you do the sums, it cheaper for them to leave out the surge
suppressor components altogether and just pay up on any such incident.
Power line surges (in the UK at least) is a vanishingly insignificant
source of damage.

--
Andrew Gabriel

In message , Andrew Gabriel
writes
In article ,
Lem writes:

What I have seen several times is damage caused by a surge
induced by lightning on a phone line.

Been there, done that :-(

Of course, the mains
surge protector will do nothing to protect against that.

So personally I don't bother using a surge protector on my PC.

Am I being too complacent?

Not in my opinion.
If I saw something at less than rip-off prices for protecting
against surge on phone line, I might consider that.

Many of the mains surge protectors also include connectors for looping
a phone line through them.

--
Richard Herring

In message , w_tom
top-posted
Again an assumption that something will stop or block a
destructive transient. Kilometers of air could not stop the
transient.

I think you need to be more quantitative here. Kilometres of air could
not stop what, exactly? They certainly do a good job of protecting me
from lightning strikes in the next village.

--
Richard Herring

Lightning is a connection from cloud to earth borne
charges. Electricity travels through kilometers of
non-conductive air. Why would some millimeters of air between
two RCD contacts stop same electricity? 1,000,000 mm of air
did not stop lightning. Why would 4 mm of RCD air stop what a
million mm could not?

The bottom line is this. Nothing is going to stop
lightning. Lightning protection is about shunting - also
called diverting, redirecting, or electrically connecting - to
earth ground. Any protector that claims to stop or block
lightning (such as in the RCD question) is simply promoting a
myth. And yet that is exactly what many people do - promote
the myth - when they recommend plug-in protectors.

In response to the OP's question. 4 mm of air inside the
RCD (open switch contacts) is not going to stop a potentially
destructive surge.

Richard Herring wrote:
In message , w_tom
Again an assumption that something will stop or block a
destructive transient. Kilometers of air could not stop the
transient.

I think you need to be more quantitative here. Kilometres of
air could not stop what, exactly? They certainly do a good
job of protecting me from lightning strikes in the next
village.

In article ,
Keith wrote:
On Fri, 09 Jul 2004 02:16:23 +0000, Gregory L. Hansen wrote:

In article , w_tom wrote:
Again an assumption that something will stop or block a
destructive transient. Kilometers of air could not stop the
transient. Do you think that silly little RCD switch contact
will do what kilometers of sky could not? Again, protection
is about shunting (diverting, connecting, shorting) a
transient to earth ground. There is no way around that
fundamental fact. Nothing is effective at stopping such
transients.

My surge protector came with a guarantee that the company will pay to
repair or replace any equipment damaged through the powerlines when it was
plugged in to their product.

Have you collected on that promise? Somehow I think you'd buy an extended
warranty on that strip too. ;-)

Haven't had anything break that was plugged into it, although the power
has flickered or quit many times during storms. But then, the TV and VCR
are still working, and they're not on a surge protector.


--
"Let us learn to dream, gentlemen, then perhaps we shall find the
truth... But let us beware of publishing our dreams before they have been
put to the proof by the waking understanding." -- Friedrich August Kekulé

w_tom wrote:
The bottom line is this. Nothing is going to stop
lightning. Lightning protection is about shunting - also
called diverting, redirecting, or electrically connecting - to
earth ground. Any protector that claims to stop or block
lightning (such as in the RCD question) is simply promoting a
myth. And yet that is exactly what many people do - promote
the myth - when they recommend plug-in protectors.

I am not naive enough to think that my little "surge protector" would
save anything from a full-on lightning strike. The issue is whether one
might reasonably expect more modest voltage transients to occur on the
mains supply (and phone line) which can be safely absorbed by such a
device, and which might otherwise disrupt or destroy delicate
electronics (equipped, perhaps, with rather cheap PSUs).

I freely admit to not knowing the answer. Your contributions make good
points about the requirements to be met in order to achieve 'proper'
surge protection, but do nothing to address this question.

In message , w_tom
writes

[top-posting corrected]

Richard Herring wrote:
In message , w_tom
Again an assumption that something will stop or block a
destructive transient. Kilometers of air could not stop the
transient.

I think you need to be more quantitative here. Kilometres of
air could not stop what, exactly? They certainly do a good
job of protecting me from lightning strikes in the next
village.

Lightning is a connection from cloud to earth borne
charges. Electricity travels through kilometers of
non-conductive air.

No, current travels through kilometres of conductive ionised air. First
you need a strong enough potential difference to produce a strong enough
electric field to cause that ionisation. Then there's a complicated
process by which the ionisation spreads to produce a complete channel.

Why would some millimeters of air between
two RCD contacts stop same electricity? 1,000,000 mm of air
did not stop lightning. Why would 4 mm of RCD air stop what a
million mm could not?

Because the potential difference across _that_ gap, and hence the field
strength, may now be insufficient to produce ionisation. Never mind how
many megavolts there were between cloud and earth, the question is how
many there are across that contact gap.

That's why I asked you to be quantitative. Qualitative language like
"same electricity", "surge" and "transient" is not helpful here. Do you
mean a current, a potential difference, an electric field, or what?

The bottom line is this. Nothing is going to stop
lightning. Lightning protection is about shunting - also
called diverting, redirecting, or electrically connecting - to
earth ground. Any protector that claims to stop or block
lightning (such as in the RCD question) is simply promoting a
myth. And yet that is exactly what many people do - promote
the myth - when they recommend plug-in protectors.

Now you're confusing two different things. Most plug-in protectors that
I've encountered do not rely on open contacts (as in the RCD) but use
some form of voltage-dependent resistor and/or spark gap to shunt the
excess potential difference to local ground. To be sure, there may be so
much inductance in the system that they are ineffective, but that's a
different issue.

In response to the OP's question. 4 mm of air inside the
RCD (open switch contacts) is not going to stop a potentially
destructive surge.

It _will_ stop a "surge" or even a "transient" up to some threshold
potential difference. What's that value, and how is it related to what's
going on in the sky outside?

--
Richard Herring

"w_tom" wrote in message
...
Hard drives can be corrupted for various reasons based also
upon what the filesystem is. For example, if using FATxx
filesystems, then a loss of electrical power at the right time
can even erase files from that drive. Just another reason why
the technically informed want NTFS filesystems on drives; not
FAT.

Transients should never be a problem to disk drives or
memory. Based upon how these devices are connected, then a
differential type transient would be required to cause
damage. But all minimally acceptable power supplies must have
the essential function called overvoltage protection - that
makes a differential transient not possible.

That is the theory as well proven by power supplies even 30
years ago. Reality is the gross profits obtained by dumping
inferior supplies in North America where so many computer
assemblers don't even have basic electrical knowledge. Many
clones are not built and sold missing the essential
overvoltage protection because the assembler only understands
one specification - dollars. It's called a bean counter
mentality. If the power supply is sold on the cheap, (ie full
retail price is less than $60), then this and other critical
functions are simply *forgotten*. Does not matter. Consumer
is only to be fleeced.

If the destructive differential transient does occur, there
is no overvoltage protection circuit to protect that hardware
- do to power supply purchased by a bean counter. No
problem. Myth purveyors then quickly blame speculated surges,
and recommend overpriced, typically undersized, and
ineffective plug-in protectors.

Up front - does the power supply specifically state that
overvoltage protection is provided? If not, then it probably
is a man-made disaster just waiting to destroy disk drive,
data, and other computer components.

This overvoltage protection is something completely
different from another disk drive threat to FAT filesystems -
blackouts and brownouts.

A brownout is generally recognized as planned voltage cuts - or
undervoltage.
My utility in the US routinely implements 3% and 5% voltage cuts to shave or
reduce peaks (and thereby save $' when buying power).

There is also the issue of spikes and harmonics.

Given a current laptop/desktop will be ~ $800USD to ~$4000 for a high
performance system and a UPS sells for $40 - why subject a computer
to unexpected power events? What is the value of the data on the hdd(s)?


"J.J." wrote:
Does anyone have a reference to HDDs getting corrupted by
power events on the mains power supply?

In article ZsAHc.14750$oh.13125@lakeread05,
"someone" writes:

A brownout is generally recognized as planned voltage cuts - or
undervoltage.
My utility in the US routinely implements 3% and 5% voltage cuts to shave or
reduce peaks (and thereby save $' when buying power).

There is also the issue of spikes and harmonics.

Given a current laptop/desktop will be ~ $800USD to ~$4000 for a high
performance system and a UPS sells for $40 - why subject a computer
to unexpected power events? What is the value of the data on the hdd(s)?

This just isn't an issue in the UK, about which the original question
was asked. Maybe it's more of a problem in the US for some reason?

--
Andrew Gabriel

No, there's no hardware nor data worth saving in the UKG.

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.

There is nothing cost effective adjacent to the computer. No
UPS nor power strip protector that will protect computer
hardware. Computer internal protection assumes the building
has implemented a 'whole house' protector on AC mains
connected less than 10 feet to central earth ground.
Protection as it was even done and well proven before WWII.

someone wrote:
A brownout is generally recognized as planned voltage cuts -
or undervoltage. My utility in the US routinely implements
3% and 5% voltage cuts to shave or reduce peaks (and
thereby save $' when buying power).

There is also the issue of spikes and harmonics.

Given a current laptop/desktop will be ~ $800USD to ~$4000
for a high performance system and a UPS sells for $40 - why
subject a computer to unexpected power events? What is the
value of the data on the hdd(s)?

First, plug-in surge protectors would not even provide
effective protection meaning that they are not even relevant
to the originally posted question. Furthermore, the little
surge protector does not absorb even modest transients.
Absorbing is not what they do.

Second, a full-on lightning strike is why we install
protectors. Modems already have significant internal
protection as part of design and to meet industry
requirements. Protection that can be compromised by a full-on
lightning strike.

Typical frequency of potentially destructive surges is once
every eight years. That number varies significantly even
between adjacent towns. So how frequent is your
neighborhood? Without information such as underlying geology
and manmade buried objects, weather trends, etc; then your
only valid information comes from history provided by long
term neighbors. Yes, even installation of new buried
utilities can change those trends.

'Whole house' protectors and earthing is so inexpensive that
US telco companies install same, for free, at every customer
interface. Question is whether the £1 per protected appliance
is necessary for a destructive transient that might occur once
every ten or so years. Points one and two define why you
would install that protector.

Pyriform wrote:
w_tom wrote:
The bottom line is this. Nothing is going to stop
lightning. Lightning protection is about shunting - also
called diverting, redirecting, or electrically connecting - to
earth ground. Any protector that claims to stop or block
lightning (such as in the RCD question) is simply promoting a
myth. And yet that is exactly what many people do - promote
the myth - when they recommend plug-in protectors.

I am not naive enough to think that my little "surge protector"
would save anything from a full-on lightning strike. The issue
is whether one might reasonably expect more modest voltage
transients to occur on the mains supply (and phone line) which
can be safely absorbed by such a device, and which might
otherwise disrupt or destroy delicate electronics (equipped,
perhaps, with rather cheap PSUs).

I freely admit to not knowing the answer. Your contributions
make good points about the requirements to be met in order
to achieve 'proper' surge protection, but do nothing to
address this question.

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

Or to avoid the expense of bringing additional generating capacity
online, thereby saving money...

All of which is irrelevant to HD protection. Either the
power supply will output correct power or it will shutdown.

A PSU shutting down is not irrelevant to HD protection. Shutdown at the
wrong moment (especially with the wrong operating system) and you end up
with a badly trashed filesystem.

I have operated computers much further from 120V with absolutely no problems.

Once at the end of 100ft extension cord along with 1500W heater, lights
dimming.

The other time at 130V, light bulbs popping every month.

Even on a generator nearly out of gas I had a minute to shutdown my system, no
corruption occured.

"someone" wrote in message
news:ZsAHc.14750$oh.13125@lakeread05...

A brownout is generally recognized as planned voltage cuts - or
undervoltage.
My utility in the US routinely implements 3% and 5% voltage cuts to shave or
reduce peaks (and thereby save $' when buying power).

There is also the issue of spikes and harmonics.

Given a current laptop/desktop will be ~ $800USD to ~$4000 for a high
performance system and a UPS sells for $40 - why subject a computer
to unexpected power events? What is the value of the data on the hdd(s)?

"w_tom" wrote in message
...
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.

True - my opinion as well - perhaps you could convince my local utility re
this procedure being used on a daily basis.

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.

There is nothing cost effective adjacent to the computer. No
UPS nor power strip protector that will protect computer
hardware. Computer internal protection assumes the building
has implemented a 'whole house' protector on AC mains
connected less than 10 feet to central earth ground.
Protection as it was even done and well proven before WWII.

Perhaps you could explain the half dozen UPS I have seen that operated
correctly and interrupted close in electrical faults.
Naturally the UPS were scrap after the electrical event - but the protected
electronics were ok.
$40 UPS vs $800 desktop or in one situation $200 - $300 UPS vs. $5000 of
servers.

someone wrote:
A brownout is generally recognized as planned voltage cuts -
or undervoltage. My utility in the US routinely implements
3% and 5% voltage cuts to shave or reduce peaks (and
thereby save $' when buying power).

There is also the issue of spikes and harmonics.

Given a current laptop/desktop will be ~ $800USD to ~$4000
for a high performance system and a UPS sells for $40 - why
subject a computer to unexpected power events? What is the
value of the data on the hdd(s)?

Was UPS between AC mains and computer? No. 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. Any transient from the
receptacle confronts UPS and computer equally. 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. 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.

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.

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, 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 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-pap...ning-guide.pdf
Lightning surges cannot be stopped, but they can be diverted.
The plans for the data center should be thoroughly reviewed
to identify any paths for surge entry into the data center.
Surge arrestors can be designed into the system to help
mitigate the potential for lightning damage within the data
center. These should divert the power of the surge by
providing a path to ground for the surge energy. Protection
should be placed on both the primary and secondary side of
the service transformer. It is also necessary to protect
against surges through the communications lines. The
specific design of the lightning protection system for the
data center will be dependent on the design of the building
and utilities and existing protection measures.

If you are suffering transient damage, then the human is
reason for failure. What Sun writes is so well proven and
understood that it was standard even before WWII. Protection
is only as effective as its earth ground.

As for your brownouts - if any voltage is too low for a
computer, then the utility has grossly violated national
standards. A PUC call would create a massive response - if
your AC voltage drops so low as to be problematic to a
computer.

someone wrote:
"w_tom" wrote in message
...
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.

True - my opinion as well - perhaps you could convince my
local utility re this procedure being used on a daily basis.

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.

There is nothing cost effective adjacent to the computer. No
UPS nor power strip protector that will protect computer
hardware. Computer internal protection assumes the building
has implemented a 'whole house' protector on AC mains
connected less than 10 feet to central earth ground.
Protection as it was even done and well proven before WWII.

Perhaps you could explain the half dozen UPS I have seen
that operated correctly and interrupted close in electrical
faults. Naturally the UPS were scrap after the electrical
event - but the protected electronics were ok. $40 UPS vs
$800 desktop or in one situation $200 - $300 UPS vs. $5000
of servers.

"w_tom" wrote in message
...

There is nothing cost effective adjacent to the computer. No
UPS nor power strip protector that will protect computer
hardware.

That's simply wrong/false. A good UPS or good surge protector WILL protect
a PC. Do you understand the concept of common mode?

Computer internal protection assumes the building
has implemented a 'whole house' protector on AC mains
connected less than 10 feet to central earth ground.

That's simply wrong/false. There is nothing magic about 10 feet
except that an electrical pulse travels about that far in 10 nanoseconds.
What do you suppose the risetime of a lightening bolt is and how
does that relate to that 10 feet?
Define "central earth ground" and what it's important characteristics are.
Where is the "central earth ground" on an airplane, car, ISS or on the
Antartic pole US base(over a mile thick cold pure ice)? Are all PCs and
electronics gadgets there doomed?
Ever heard on the concept of a Farady cage?

Protection as it was even done and well proven before WWII.

Yes, for those who actually understand it. What does the "central earth
ground"
look like at a major power station, substation or hydroelectric dam?
Where's it located?

Again, the trashed filesystem is a problems of FAT and other
simplistic file systems. It is not a problem to superior
(journalizing) filesystems.

Will a disk drive write to the platter as voltage drops? Of
course not. The disk drive controller is a complete computer
that also monitors voltage. It does not matter to disk
hardware when power is turned off. But it does matter to some
'simplistic' disk filesystems that power is not removed during
a write operation.

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

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

Or to avoid the expense of bringing additional generating
capacity online, thereby saving money...

All of which is irrelevant to HD protection. Either the
power supply will output correct power or it will shutdown.

A PSU shutting down is not irrelevant to HD protection.
Shutdown at the wrong moment (especially with the wrong
operating system) and you end up with a badly trashed
filesystem.

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).

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?

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, 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? 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:


Ron Reaugh wrote:
"w_tom" wrote in message
...
There is nothing cost effective adjacent to the computer. No
UPS nor power strip protector that will protect computer
hardware.

That's simply wrong/false. A good UPS or good surge
protector WILL protect a PC. Do you understand the concept
of common mode?

Computer internal protection assumes the building
has implemented a 'whole house' protector on AC mains
connected less than 10 feet to central earth ground.

That's simply wrong/false. There is nothing magic about 10
feet except that an electrical pulse travels about that far
in 10 nanoseconds. What do you suppose the risetime of a
lightening bolt is and how does that relate to that 10
feet? Define "central earth ground" and what it's
important characteristics are. Where is the "central earth
ground" on an airplane, car, ISS or on the Antartic pole
US base(over a mile thick cold pure ice)? Are all PCs and
electronics gadgets there doomed? Ever heard on the concept
of a Farady cage?

Protection as it was even done and well proven before WWII.

Yes, for those who actually understand it. What does the
"central earth ground" look like at a major power station,
substation or hydroelectric dam? Where's it located?

w_tom wrote:
Furthermore, the little
surge protector does not absorb even modest transients.
Absorbing is not what they do.

I say absorb; you say shunt. We mean the same thing. Energy that would
have entered the 'protected' load instead goes somewhere else. So unless
you are arguing purely on the basis of semantics, your claim that even
"modest transients" are not absorbed by plug-in surge suppressors is
clearly false. What I want to know is whether such transients are
actually found, and whether they pose a threat to 'unprotected'
equipment.

Your "unless it protects against everything, it protects against
nothing" argument is not entirely convincing.

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?

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

Ron Reaugh wrote:
"w_tom" wrote in message
...
...
Computer internal protection assumes the building
has implemented a 'whole house' protector on AC mains
connected less than 10 feet to central earth ground.

That's simply wrong/false. There is nothing magic about 10
feet except that an electrical pulse travels about that far
in 10 nanoseconds. What do you suppose the risetime of a
lightening bolt is and how does that relate to that 10
feet? Define "central earth ground" and what it's
important characteristics are. Where is the "central earth
ground" on an airplane, car, ISS or on the Antartic pole
US base(over a mile thick cold pure ice)? Are all PCs and
electronics gadgets there doomed? Ever heard on the concept
of a Farady cage?
...

"w_tom" wrote in message
...
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. He
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 wrote:
"w_tom" wrote in message
...
There is nothing cost effective adjacent to the computer. No
UPS nor power strip protector that will protect computer
hardware.

That's simply wrong/false. A good UPS or good surge
protector WILL protect a PC. Do you understand the concept
of common mode?

Computer internal protection assumes the building
has implemented a 'whole house' protector on AC mains
connected less than 10 feet to central earth ground.

That's simply wrong/false. There is nothing magic about 10
feet except that an electrical pulse travels about that far
in 10 nanoseconds. What do you suppose the risetime of a
lightening bolt is and how does that relate to that 10
feet? Define "central earth ground" and what it's
important characteristics are. Where is the "central earth
ground" on an airplane, car, ISS or on the Antartic pole
US base(over a mile thick cold pure ice)? Are all PCs and
electronics gadgets there doomed? Ever heard on the concept
of a Farady cage?

Protection as it was even done and well proven before WWII.

Yes, for those who actually understand it. What does the
"central earth ground" look like at a major power station,
substation or hydroelectric dam? Where's it located?

"w_tom" wrote in message
...
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.

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

Ron Reaugh wrote:
"w_tom" wrote in message
...
...
Computer internal protection assumes the building
has implemented a 'whole house' protector on AC mains
connected less than 10 feet to central earth ground.

That's simply wrong/false. There is nothing magic about 10
feet except that an electrical pulse travels about that far
in 10 nanoseconds. What do you suppose the risetime of a
lightening bolt is and how does that relate to that 10
feet? Define "central earth ground" and what it's
important characteristics are. Where is the "central earth
ground" on an airplane, car, ISS or on the Antartic pole
US base(over a mile thick cold pure ice)? Are all PCs and
electronics gadgets there doomed? Ever heard on the concept
of a Farady cage?
...

"w_tom" wrote in message
...
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-pap...ning-guide.pdf
Lightning surges cannot be stopped, but they can be diverted.

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

The plans for the data center should be thoroughly reviewed
to identify any paths for surge entry into the data center.
Surge arrestors can be designed into the system to help
mitigate the potential for lightning damage within the data
center. These should divert the power of the surge by
providing a path to ground for the surge energy. Protection
should be placed on both the primary and secondary side of
the service transformer. It is also necessary to protect
against surges through the communications lines. The
specific design of the lightning protection system for the
data center will be dependent on the design of the building
and utilities and existing protection measures.

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.

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
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Posting from Brazil. | This pain is just too real
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