lightning strike on the computer

Discussion in 'Computer Support' started by jw 1111, Sep 10, 2005.

  1. jw 1111

    jw 1111 Guest

    Hi, a friends computer yesterday was 'done in' by overhead thunder and

    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.
    jw 1111, Sep 10, 2005
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  2. jw 1111

    Toolman Tim Guest

    Lightning damage can come occur to anything on the power mains, and the
    phone line, and the TV ariel or cable. If you can disconnect, do so. I can't
    get behind the fridge, but many times those get blown. TVs also go out
    often, computers even more often. Any electronics or appliance can be
    damaged. Anytime I know a storm is close I try to get the electronics

    At the office we had many computers on standard APC surge protectors with
    the $10,000 guarantee. One strike we lost 5 computers (out of 20) even with
    the surge protectors in place. I replaced the power supplies and sent the
    receipt and a bill for my labor to APC and they paid it without a hitch.
    Toolman Tim, Sep 10, 2005
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  3. 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, Sep 10, 2005
  4. 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.
    =?ISO-8859-1?Q?R=F4g=EAr?=, Sep 10, 2005
  5. Okay, I misspelled "lightning" but I'm still not a-joking.
    =?ISO-8859-1?Q?R=F4g=EAr?=, Sep 10, 2005
  6. 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.
    Shenan Stanley, Sep 10, 2005
  7. You sir, are full of it. I don't mean shit, I mean knowledge with not a
    lot to back it up. I'm not much better. So please try not to be too
    offended. All these surge protectors, including UPS's, offer so little
    protection that it's frightening. Yes, you can kill almost any
    electronic device with EMS. Don't give a shit how clamped down you are
    with your copper rods and stuff. *But* if you have a really good earth
    connection, are carefull about how things are wired you do seem to have
    a better chance. I use Phasar lightning protection on my outdoor
    wireless stuff. In at least one instance that's on top of a tower on top
    of a mountain, it gets hit about thrice a month (rough estimate)
    directly by lightning. Not lightning in the area, not EMI, direct hits.
    I've had to replace all sorts of shit there. Ever seen a little 802.11b
    radio exposed to 300 billion volts of electricity? Scotty can't turn up
    the power there, it's already maxed out.
    =?ISO-8859-1?Q?R=F4g=EAr?=, Sep 11, 2005
  8. jw 1111

    Buffalo Guest

    Well, no wonder.
    Every time I expect a thunderstorm, I unplug all appliances and also do the
    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.
    Buffalo, Sep 11, 2005
  9. I'm in a rather high lightning risk area. I never unplug anything except
    my Aunt Virgie's life support. She's proned to getting an electronic
    thrill and I can't get her off the water-meter reader for several days.
    =?ISO-8859-1?Q?R=F4g=EAr?=, Sep 11, 2005
  10. jw 1111

    w_tom Guest

    First we will dispell rumors that are so commonly promoted
    with this subject. Your telephone compnay has wires
    everywhere in town directly connected to their $multi-million
    computer. If that computer is damaged, then figure about 5
    days to replace it. Reality, they keep that computer running
    and connected to all those overhead wires during every
    thunderstorm and suffer no such damage.

    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.
    w_tom, Sep 11, 2005
  11. jw 1111

    Buffalo Guest

    Buffalo, Sep 11, 2005
  12. jw 1111

    dadiOH Guest

    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'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
    dadiOH, Sep 11, 2005
  13. jw 1111

    Trax Guest

    |> First we will dispell rumors that are so commonly promoted
    |>with this subject. Your telephone compnay has wires
    |>everywhere in town directly connected to their $multi-million
    |>computer. If that computer is damaged, then figure about 5
    |>days to replace it. Reality, they keep that computer running
    |>and connected to all those overhead wires during every
    |>thunderstorm and suffer no such damage.

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

    4 High School Golfers Struck By Lightning, 1 Critical
    Trax, Sep 11, 2005
  14. jw 1111

    w_tom Guest

    Buy a surge protector only for insurance - that is exempt
    from federal laws? If one needs insurance, then one goes to a
    license broker who must honor the claim. Since plug-in
    protectors are so ineffective, then myth purveyors promote
    this warranty hype. Did you read the long list of exemptions
    with that warranty? Some even state that the existence of a
    protector from another manufacturer voids the warranty. The
    warranty is so chock full of exemptions that it will not be
    honored as so many hope:
    Newsman on 10 Sept 2002 in the newsgroup
    entitled "SONY TiVo SVR-2000"
    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
    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).

    This is about secondary protection. Not discussed
    previously is primary protection as demonstrated in these
    w_tom, Sep 11, 2005
  15. jw 1111

    dadiOH Guest

    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.


    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
    dadiOH, Sep 11, 2005
  16. jw 1111

    J-McC Guest

    People under estimate the power and danger of lightning, we had a hit
    near the computer centre at the place where I used to work. It blew
    the daylights out of a 11kv underground mains cable, and damaged
    nearly all of the p/cs on site, approx 400. I was astounded to see
    the tops of ics just blown off and holes in memory chips. In those
    days we had a mainframe and used rs232 links to all the desktop
    computers. Now most of the buildings have a fibre link back to the
    comp-centre and then the usual cat5 within a building.
    The little lightning surge busters were evaporited all that was left
    was part of their leads.
    It cost well over $aud500k to rectify plus the cost of salaries of
    scientific staff who were not very productive till the computers were
    repaired, most by replacement. The Compaqs,Hp and IBM did fare
    slightly better than the clones but in the end most were stuffed.
    J McC
    J-McC, Oct 2, 2005
  17. jw 1111

    w_tom Guest

    A spark plug fires and moves tons of automobile. Clearly we
    have underestimated the power of a spark plug. Same reasoning
    used to claim damage was from the 'power of lightning'.
    Instead we consult industry experts: Martin A Uman in "All
    About Lightning"
    From From Colin Baliss in "Transmission & Distribution
    Electrical Engineering":
    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

    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:
    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
    w_tom, Oct 2, 2005
  18. jw 1111

    Charlie Tame Guest

    Oh good, once again society is to blame then :)

    Charlie Tame, Oct 2, 2005
  19. jw 1111

    w_tom Guest

    Your telephone company connects overhead wires everywhere in
    town to a $multi-million computer. Do they have the damage
    from direct strikes that J-McC details? Of course not.
    Lightning can initiate significant damage. Society is not at
    fault. But some humans fail to learn well proven lightning
    protection techniques that the phone company was using even in
    the 1930s. Society has long since learned how to make
    lightning damage irrelevant. But some humans today still have
    not learned that 1930s technology.

    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.
    w_tom, Oct 2, 2005
  20. jw 1111

    Buffalo Guest

    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
    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?
    Buffalo, Oct 2, 2005
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