lightning strike on the computer

what precautions should one take in that situation ? should one disconnect
the pc from the telephone lead and/or the mains. what about tv and vcr ?
are these surge protector things worth buying and if one has one; it is best
to still disconnect to be on the safe side? thanks for any advice.

Get a $35-$800 UPS system. (Yeah - the numbers range - but it depends how
much run time you wantr, etc. heh)

Run your telephone and/or network through the surge arrest system as well.
For most home users, a 300-1000VA system will be more than sufficient.

For other electronic equipment - you should always hook them in through a
surge arrestor strip of some sort - at least.

--
Shenan Stanley
MS-MVP
--
How To Ask Questions The Smart Way
http://www.catb.org/~esr/faqs/smart-questions.html

These other well-meaning people are semi-correct. I had a 32" TV taken
out by EMI even though it was completely disconnected from electrical or
cable connections. There ain't no guarantees in this stuff. If the
computer or other device is plugged in by any sort of connection,
there's a way for it to get fried. If it's not plugged up to any wire,
then EMI (look it up) can still get it. I'm not a-joking, you can
completely disconnect your computer from every damn wire in the world
and lightening can still screw it up even though it struck a mile down
the road.

Okay, I misspelled "lightning" but I'm still not a-joking.

No one suggested you would be 100% safe.. The tree outside gets struck by
lightning and falls on your house and crushes your TV - the surge protector
did nothing... Or if it catches your home on fire (directly or
indirectly) - surge protector worthless.. It can even just have enough
charge in the air around the equipment to burn it out..

However - since it is more likely a lightning strike will hit something else
before your home and travel through a wire to your electronic equipment in a
surge.. Then it is logical to get something that can help prevent that to
protect your investment to the best of your ability. While you can never
protect against everything, only the foolish would not take the precautions
they are able to take..

The way the OP made it sound - there was NO protection (or a "Dollar Store
special" surge protector) for the equipment. Depending on the storm, I will
either trust or not the 1000VAs I have connected to my computer equipment.
Too many factors to list - but it's a call only the person who owns the
stuff and knows their homes wiring situation and such can make.

Well, no wonder.
Every time I expect a thunderstorm, I unplug all appliances and also do the
following:
I put my PC, the TV and the Refrigerator (unplugged of all wires of course) on
my bed and covered them with my non-electrostatic quilt,and then, if the storm
is going to last during the night, I connect a copper wire to my left big toe
with the other end connected to the cold water pipe. I have never lost my PC,TV
or fridge, but I did lose part of my left big toe.

PS: Next time when you disconnect your TV , don't put it outside in the rain.

Commerical radio stations are routinely struck by direct
lightning strikes without any damage.

911 and telco operators don't remove headsets and leave the
room when thunderstorms arrive. If what others claim was
true, then those operators would have to remove headsets with
every storm.

Well over 95% of all trees struck have no appreciable
indication. Many simply see the rare exception and assume
that damage is routine for lightning. The point is that
direct lightning strikes routinely cause no damage IF you
learn and install a simple basic system.

Second, we move on to effective protection verses mythical
protection. If you think for one minute that a protector sits
between lightning and your computer - stops, blocks, or
absorbs what three miles of sky could not stop - then you are
ripe to be scammed. The is what plug-in protectors would have
you believe to sell undersized protectors (see the number for
joules). Many make the assumption that a surge protector and
surge protection are same thing. This being a myth encouraged
by ineffective protectors so often seen on shelves in Circuit
City, Sears, Radio Shack, CompUSA, Walmart, Best Buy, Staple,
Kmart and Office Max.

Step one to effective protection is the building's single
point ground. Earthing that is required in buildings that
meet post 1990 National Electrical Code and rarely sufficient
in buildings that predate those requirements. The 1990 code
does not define earthing for surge protection. And that
grounding may not be sufficient by itself. But this is the
sentence you must comprehend. "No earth ground means no
effective protection".

No earth ground is what ineffective protectors must forget
to mention to sell their overpriced products. What does that
telco do to protect their computer? Every utility wire that
enters a building first connects to the single point earth
ground. It dumps the direct lightning strike to earth before
entering the building. That earthing connection for a
residential building would be a direct wire connection (ie
CATV, satellite dish), or it would be a connection via a
'whole house' protector (ie. AC electric, telephone). 'Whole
house' protectors are so inexpensive and so effective as to be
installed, for free, on an incoming phone line. But THE wire
most often struck is also THE wire highest on utility poles.
Wire that most often carries a destructive transient into
electronics is AC electric. Most common source of incoming
transients that destroy computer modems is AC electric.

Notice what effective protection does. It does not stop,
block, or absorb as myth purveryors would have you believe.
The effective protectors simply shunts (connects, distributes)
a surge from one wire to all others. It does what Ben
Franklin demonstrated in 1752. If that earthing wire is a
'less than 10 foot' connection to a building's single point
earth ground, then effective protection exists. If that
protector is a plug-in type (adjacent to the computer), then a
surge has been provided more paths to find earth ground,
destructively, via that powered off computer. This little
fact is why plug-in protector manufacturers simply avoid all
discussion about earthing to sell a grossly undersized,
ineffective, and overpriced protector.

Effective 'whole house' protectors are sold by manufacturers
with responsible names such as Square D, Leviton, Cutler
Hammer, Intermatic, Siemens, Polyphaser, and GE. Two sources
of effective 'whole house' protectors are Home Depot
(Intermatic) and Lowes (Cutler Hammer and GE).

But again, the protector is only a connection to earth
ground. That connection must be short (ie 'less than 10
feet'). At minimum, that earth ground would be a ten foot
copper ground rod. Everything incoming must connect short to
this rod. In some locations, even that ground rod may not be
sufficient. But this is the bottom line: the protector is
only as effective as its earth ground. Those who promote
ineffective plug-in protectors will simply ignore THE most
critical component in a surge protection 'system'. An
effective protector makes a short connection to that critical
component: earth ground.

What protects everything in the house? 'Whole house'
protectors and every incoming utility connects to that single
point earth ground before entering the building.

Yeah. Not so much because they will keep something from being fried but
because they will pay for the damage.

That said, you need to get one from a manufacturer who pays off promptly
and doesn't try to make a federal case out of the paper work. One such
is Belkin.

There is lots of lightning here in central Florida and when I was on
dial up I probably had 4-5 modems fried over a couple of years.
Additionally, one big storm took out the mobo and more in two different
computers. In one of them (an old HP), the mobo was no longer available
so had to replace other stuff too. To make a long story short, total
damage on both computers was $700+ and Belkin paid off promptly and in a
helpful manner.

--
dadiOH
____________________________

dadiOH's dandies v3.06...
...a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

I heard that surge protector has only limited use.

sit down and read (provided you have power) some book because you may have
to disconnect TV and cable connection.

"dadiOH" <dad...@wherever.com> wrote in message
news:cdVUe.4642$Hs6.1386@trnddc07...

Don't need no stinking wires, golf clubs work just fine.

4 High School Golfers Struck By Lightning, 1 Critical
http://www.local6.com/weather/4956435/detail.html

--

http://www.zimbra.com/

Did you read all those exemptions? A surge protector is for
hardware protection only. Benchmarks in surge protection -
products that are most effective - offer no warranty. Note
the trend. A less warranty is typical of better protection.
Real world protector have responsible manufacturer names such

This is about secondary protection. Not discussed
previously is primary protection as demonstrated in these
pictures:
http://www.tvtower.com/fpl.html

Works for me...

I have had numerous claims, all were paid promptly. All were from
Belkin except one; that one was a bit of a hassel but was paid.

It is a numbers game for the companies...sell jillions of protectors
which result in a miniscule number of claims. As I said, works for me.

From From Colin Baliss in "Transmission & Distribution
Electrical Engineering":
> Although lightning strikes have impressive voltage and current
> values (typically hundreds to thousands of kV and 10-100 kA)
> the energy content of the discharge is relatively low and most
> of the damage to power plant is caused by 'power follow-through
> current'.

Now examples of what these men note. Also note the
difference between power and energy.

Lightning seeks earth ground via a transformer. The
transformer was not properly earthed. Lightning first forms a
plasma path across the transformer; then discharges. But that
plasma path remains after lightning has discharged.
'Follow-through current' (from AC electric primary wire to AC
electric secondary wire) causes the transformer to explode;
does not come from the little energy numbers in lightning.
The explosive energy comes from high energy numbers in AC
utility electricity. One should first learn numbers before
speculating what is and is not high energy - not to be
confused with high power.

A human only speculates when he does not first learn the
numbers. He saw massive damage and then *assumes* all that
energy was from lightning - even though damage involved a high
energy 11,000 volt AC utility wire.

Why does lightning setup such damage? Because a human has
failed to properly earth. For an AC electric transformer,
pictures demonstrate where protection must be inspected - by a
human:
http://www.tvtower.com/fpl.html

Furthermore, every incoming utility must be earthed to a
common point before entering the building. Essential earthing
- protection well proven even in the 1930s - would be missing
to have damage described by J-McC. This was described in an
earlier post in this discussion.

If the human thought those adjacent 'lightning surge
busters' provided effective protection, well, the human again
has failed to first learn basic lightning protection concepts;
failed to read that earlier post. The human has again
assumed "surge protector equals surge protection". Others in
this same discussion also had fallen for that propaganda. The
human is advised to read an earlier post in this same
discussion on 10 Sept 2005, also posted at:
http://tinyurl.com/dgrpt
that includes this phrase:

Lightning can build plasma wires that, in turn, can cause
massive "damage ... caused by 'power follow-through
current'." This because lightning was not properly earthed by
humans. No earth ground means no effective lightning
protection.

Charlie

"w_tom" <w_t...@hotmail.com> wrote in message
news:43400D7E...@hotmail.com...

Of course, we could blame it on the education system, the
unions, religious leaders who preach blasphemy, ... and lets
not forget the most evil of all ... the tax man.

I don't understand the"little energy numbers in lightning" statement.
Do you mean that although a lightning bolt has an extremely high amount of
potential power, very little of it was dissipated?
Don't trees literally blow apart from a lightning strike (sap vaporizing super
fast)?
Copper water pipes have been known to blow out of the ground (from over 6 feet
burial) due to a lightning strike.
Perhaps a simpler explanation.
Did the follow through current come from the collapsing plasma field?
Where does the "power follow-through current" come from?
The AC? What causes the follow-through current?

For example, to put this energy into numerical perspective,
from:
http://www.weatherwise.org/qr/qry.lightningpower.html
> A kilowatt hour is 3.6 million joules. ... we should consider
> only the electrical energy available at the bottom of the stroke
> for capture and storage. For an average stroke that is probably
> less than ten million joules.

Don Kelly in newsgroup sci.physics.electromag on 4 Nov 2000
entitled "Oddball question":
> In a large storm, there is an appreciable amount of energy but
> most of this is dissipated as heat and light in multiple
> strokes over the duration of the storm (and a wide area) ...
> A typical stroke will reach its peak in about 1-2 microseconds
> and die to about half peak in 50-100 microseconds. Millionths
> of seconds, not seconds! There may be several strokes in the
> same path but even 3-5 strokes will take less than 1/1000
> second. The strokes just appear to last seconds.
> Yes there is a high peak power in a stroke but this does not
> translate into appreciable energy (about 55 KWH (200MJ)for an
> average stroke). Energy is what we need, not high peak power.
> Allowing an extremely (ridiculously so) optimistic 50% energy
> recovery and noting that a high isokeraunic level may be 8-10
> strokes/square Km /year- this translates to about 220-275
> KWH/ sq Km/year.
> A 25 watt bulb running for the full year will require
> 220KWH/year so a storm could supply one 25 watt bulb
> /sq Km/year.

Furthermore, the energy dissipation at the strike location
is made trivial by how well that stuck item is connected to
earth. Therefore direct lightning strikes even stopped harming
church steeples starting in 1752. Well earthed lightning rods
often have no strike indication other than a loud noise after
that strike. But when so many only see a direct strike to a
poorly earthed item, (meaning energy dissipation is higher),
then they assume the direct lightning strike must have high
energy.

To better appreciate the concept, one must first learn
concepts such as ideal current source. Meanwhile, plasma
fields don't collapse. That is confusing electric and
magnetic fields with particles (matter) called plasma.

Without numbers, one has no idea. It is an old propaganda
technique practiced by Goebals, Radio Moscow, and Rush
Limbaugh. Forget to provide numbers so that no one will ask
embarrassing questions. Provided are numbers from those who
do the work. What really was the source of energy through
that pipe? Lightning - or a 'follow-through current' that was
defined in the previous post?

Keep in perspective. That means numbers. How much current
can flow through that AC electric wire inside the dwelling
walls without vaporizing? Up to 300 amps continuous. AND
hundreds of thousands of amps for a short duration. But
again, the numbers.

First define what you consider high energy - the numbers.
Experts who have studied lightning for their entire
professional life don't find these high energy numbers that
myths use to hype fear and loathing. More sources with
knowledge and the numbers are cited.

Cited is the example of an exploding power transformer - not
destroyed by lightning but instead destroyed by AC utility
power - an example of 'follow-through current' that has high
energy.

These were usually not as big as the US multibeam high gain things but
nevertheless pretty big and either H shaped or X shaped.

Normally they were mounted on a chimney, and many in those days had coal
fires.

In fact the "Attractant" if that's the right word was not the TV antenna but
the rising column of ionized gas from the fire, apart from the obvious fact
that the chimney was the highest point.

TV makers started adding bleeder resistors across the antenna inputs, in
those at least one element was a "Floating" rod rather than a wrapped dipole
in an effort to drain static, but many TV's had no ground connection anyway
so I guess the drain was to mains neutral. Nevertheless better than nothing
perhaps.

Nowadays with UHF the antenna is much smaller and there is in effect a DC
short across the antenna inputs but still no proper ground in most cases.

Charlie

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