Pull the wall plug or not?

Discussion in 'NZ Computing' started by texan.usenet, Sep 6, 2004.

  1. texan.usenet

    texan.usenet Guest

    We have many thunderstorms some very severe, some not, along with
    outages.

    Normally when we have a t/storm I turn off the computer, monitor etc.
    Everything is connected into surge protector units that are the
    correct rated j.
    However when watching a weatherman on the Weather Channel, he said it
    is best to unplug everything including surge protectors from the
    wall.

    We have surge protectors on just about everything because of the
    sudden outages that can range from a second or two [often repeatedly]
    to several hours. What alerts us is the carbon monoxide detector
    which is plugged into a wall socket - it fair screams everytime power
    goes off and on [hence the knowing how frequent and short outages can
    be].

    Last Friday night, we were outside when there must have been a surge
    or two. Our cable box blew [are these so sensitive to power
    outages as this is about the 4th one that has gone after either a
    storm or outage]. The next morning, the power company had all their
    big trucks in the area - the neighbour's water well pump had also
    blown.

    So, opinions please - does one really need to disconnect the power
    surge unit from the wall after turning off anything connected to it?

    Cath
     
    texan.usenet, Sep 6, 2004
    #1
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  2. texan.usenet

    steve Guest

    Don't surge protectors only work one time?

    Or have you got the more expensive sort that can be reset?
     
    steve, Sep 6, 2004
    #2
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  3. I would unplug - and don't use the phone !!
     
    Jed Meisterdude, Sep 6, 2004
    #3
  4. texan.usenet

    EMB Guest

    Yep, pull the plug at the wall. Lightning will jump an open switch, and
    won't even stop to look at a surge protector. When I was in the Fire
    Service we were called to a lightning strike - the power pole outside a
    house had been hit. Inside the house everything that was plugged in was
    either blackened and smoking, or totally denatured. The home theatre
    system that was plugged into a surge protector was a large heap of
    smoking objects, lightswitches were blown off walls, the telephone had
    ceased to exist, the fridge had moved itself halfway across the kitchen.
    However the appliances and computers that weren't plugged in were fine.

    Most scary was all the metal slimline on the corners of the gib board
    had provided some sort of path for the electricity and all the stopping
    over it had been blown off and had burnt holes in whatever it landed on.
     
    EMB, Sep 6, 2004
    #4
  5. texan.usenet

    Roger_Nickel Guest

    Lighting that can arc through a kilometre or so of free air won't have
    much trouble jumping across a few millimetres in a switch. Overhead
    power lines are prime candidates for lightning strike. These power lines
    have spark gaps to protect against lightning strike but a direct hit
    anywhere near your house will toast your surge arrestors and your
    computer ( and your TV, audio system etc.). If in doubt, pull the plug.
     
    Roger_Nickel, Sep 6, 2004
    #5
  6. texan.usenet

    w_tom Guest

    Cath's experience is typical of a direct electrical
    connection from cloud to earth. For example, one typical path
    to earth is via AC electric (wires highest on pole are the
    most often struck), through house (because 'whole house'
    protection system was missing or compromised), and into earth
    via water pump.

    As with the open switch example, no protector that will
    stop, block, or absorb what could not be stopped by 3 miles of
    non-conductive sky. And yet we routinely suffer direct
    lightning strikes without damage - when a human learns the
    basic concepts. For example, 25 direct strikes annually to
    electronics on the Empire State Building and 40 annually on
    the WTC without damage. How? We learn from Ben Franklin's
    1752 experiment.

    Lightning seeks earth ground via a church steeple. Give
    lightning a better path to earth and the church steeple is not
    struck. Its called a lightning rod or a Franklin air
    terminal. Is a lightning rod the protection? Of course not.
    The lightning rod is only as effective as the earth ground to
    which it connects. Enhanced earth grounding means a lightning
    rod is even more effective. Notice the most important
    component for effective protection - earthing.

    Same concept protects transistors. Again, only the silly
    ones who promote plug-in protectors believe we will stop or
    absorb such surges. Surge protectors don't do what plug-in
    protector manufacturers would have us believe. Real world
    protectors *earth* a transient before it can enter a
    building. Its called 'whole house' protection. Every
    incoming utility wire must enter the building at a common
    service entrance to make a 'less than 10 foot' connection to a
    single point earth ground.

    Note some of the phrases that are so critical. 'Single
    point' and 'less than 10 foot'.

    So what does an effective surge protector do? Some wires
    such as satellite dish and cable directly connect to earth.
    No protector required. But if we direct earth incoming (hot)
    AC electric and telephone, then no utility service is
    provided. We install a surge protector so that those wires
    are earthed only during a surge.

    IOW they are called shunt mode protectors for good reason.
    Adjacent to a computer or cable box, they only shunt the surge
    into those adjacent transistors. What kind of protection is
    that? Ineffective. But connected 'less than 3 meters' to
    earth means that same protector shunts to earth ground. The
    latter is called effective protection. Just like in the Ben
    Franklin example, a protector is only as effective as its
    earth ground.

    A protector is not protection. Each are separate components
    of a surge protection 'system'. Some incoming utility wires
    don't require a protector; only a short connection to
    protection. Others require a protector to connect to
    protection. The bottom line: a surge protector is only as
    effective as its earth ground. No earth ground means no
    effective protection which is why ineffective plug-in
    protectors avoid all discussion about earthing.

    And so we are now ready to answer the question. Are surge
    protectors a 'one shot' device? Well, if selling ineffective,
    grossly overpriced protectors without a dedicated earth ground
    protection, then why waste money installing sufficient joules?
    Ineffective protectors are about enriching their manufacturers
    - not about protection.

    Life expectancy of a protector is measures in joules.
    'Whole house' protectors are sufficiently sized to earth a
    direct lightning strike and remain functional. But
    ineffective protectors profit when so grossly undersized as to
    fail. Destroyed by a surge too small to even overwhelm
    computer or cable box internal protection, but sufficient to
    destroy the protector. Then a naive human *assumes* the
    protector failed to save his transistors. Wrong. Electronic
    appliance typically contain any protection that is effective
    at the appliance. Internal protection that assumes the
    incoming transient will be earthed before entering a building.

    Protector failed because it was grossly undersized as well
    as overpriced. Very profitable to the same manufacturer who
    must also avoid discussion about earthing. Why? Too many
    'expert' without basic electrical knowledge recommend that
    "protector that sacrificed itself to protect my computer".
    Reality - computer protected itself while a grossly undersized
    protector failed catastrophically.

    A surge protector is only as effective as its earth ground.
    How to identify ineffective protectors? 1) No dedicated
    connection to a building's single point earth ground AND 2)
    manufacturer avoids all discussion about earthing - even
    though Ben Franklin demonstrated the concept in 1752.
    Effective surge protectors shunt a direct lightning strike to
    earth ground and remain fully functional. Typically at a cost
    of about $1 per protected appliance.
     
    w_tom, Sep 7, 2004
    #6
  7. My take is this: in a serious thunderstorm I disconnect every device
    that is connected to both phone network and power from one or the other
    (cordless phone, computer w. modem, answer machine, fax etc). These
    devices are prime candidates for shunting lightening surges that
    originate miles away.

    To protect against direct strikes on power lines within 1 km from your
    home you'd have to pull the plug, no question. I am usually willing to
    take that risk and not do anything of the kind unless we have a very
    violent thunderstorm directly overhead. But I always do the former if I
    so much as hear thunder. Having lost 3 modems over the years I can say I
    have learned my lesson :)

    -Peter
     
    Peter Huebner, Sep 8, 2004
    #7
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