Joules of surge protection needed?

Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

How much surge protection, in joules, does one actually need for home
computing system, including all-in-one pscf-machine? Are certain brands
preferable to others? TIA, s.
14 answers Last reply
More about joules surge protection needed
  1. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    OMG here we go again.....................

    "sdlomi2" <sdlomi2spamfree@yahoo.com> wrote in message
    news:10ft3a08crs71c2@corp.supernews.com...
    > How much surge protection, in joules, does one actually need for
    home
    > computing system, including all-in-one pscf-machine? Are certain
    brands
    > preferable to others? TIA, s.
    >
    >
  2. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    "JAD" <Kapasitor@coldmail.com> wrote in message
    news:10ft8jr9pbt5k6d@corp.supernews.com...
    > OMG here we go again.....................
    >
    > "sdlomi2" <sdlomi2spamfree@yahoo.com> wrote in message
    > news:10ft3a08crs71c2@corp.supernews.com...
    > > How much surge protection, in joules, does one actually need for
    > home
    > > computing system, including all-in-one pscf-machine? Are certain
    > brands
    > > preferable to others? TIA, s.
    > >
    > >
    >
    >
    I sincerely apologize to you, Tad, if I somehow offended you by asking
    this question. But, not knowing, and finding, by searching FIRST, not even
    ONE response/post using the word "joule" in this entire newsgroup, I felt I
    might utilize the group for its intended use. Felt sure there are
    knowledgeable people who might agree to share info on this site.
    Again, I'm sorry you felt the need to respond--esp. since I learned very
    little from it.
    Sincerely, s
  3. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    "sdlomi2" <sdlomi2spamfree@yahoo.com> wrote in message
    news:10ft3a08crs71c2@corp.supernews.com...
    > How much surge protection, in joules, does one actually need for home
    > computing system, including all-in-one pscf-machine? Are certain brands
    > preferable to others? TIA, s.

    There's an article in the latest (August) issue of PCWorld on what they
    refer to as "PC Myths". One, in particular, deals with surge suppressors
    and, according to PCWorld, refutes the notion that a pricey surge protector
    affords more protection that the cheapo models. The article contains a
    statement from a presumed expert that the number of joules is *not* a
    reliable indication of quality and all that's important is that the device
    is UL 1449 rated. All this, of course, seems to fly in the face of
    everything we've previously read or heard on this subject. Here's the link
    to the article:
    http://www.pcworld.com/news/article/0,aid,116572,pg,5,00.asp

    Art
  4. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    "Art" <Anonymous@notanisp.com> wrote in message
    news:dJmdnbz9bIQ4KmPdRVn-jQ@adelphia.com...
    > "sdlomi2" <sdlomi2spamfree@yahoo.com> wrote in message
    > news:10ft3a08crs71c2@corp.supernews.com...
    > > How much surge protection, in joules, does one actually need for
    home
    > > computing system, including all-in-one pscf-machine? Are certain
    brands
    > > preferable to others? TIA, s.
    >
    > There's an article in the latest (August) issue of PCWorld on what they
    > refer to as "PC Myths". One, in particular, deals with surge suppressors
    > and, according to PCWorld, refutes the notion that a pricey surge
    protector
    > affords more protection that the cheapo models. The article contains a
    > statement from a presumed expert that the number of joules is *not* a
    > reliable indication of quality and all that's important is that the device
    > is UL 1449 rated. All this, of course, seems to fly in the face of
    > everything we've previously read or heard on this subject. Here's the link
    > to the article:
    > http://www.pcworld.com/news/article/0,aid,116572,pg,5,00.asp
    >
    > Art
    >
    >
    Thx, Art. Going there now. Have a good day,s
  5. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    Reread that PC World article with care. UL1449 2nd edition
    does not claim a surge protector is effective. UL1449 only
    says the protector does not harm humans. Article even says
    that. A protector with ineffective components could still be
    approved for UL1449 if it does not harm humans. Computer
    protection is completely irrelevant to Underwriters Labs.

    Surge protectors meet two important criteria. 1) Protector
    must be sufficiently sized to remain functional after each
    surge. 2) Protector must make a short conductive connection
    to common earth ground so as to provide that protection.

    Many plug-in protectors are grossly undersized - as
    indicated by their joules number. Review manufacturer data
    sheets and their charts such as:
    http://www.europechemicon.de/ecc01/Products/varistor/va-pulselife-e-010928.pdf
    For surges of constant value, then more joules means a
    protector will survive more surges. The relationship is
    exponential. For example, a plug-in protector rated at 345
    joules may actually use as little as 115 joules in protection
    and never more than 230 joules. Assume this 115 joules only
    survives two or three same size surges. Then the properly
    sized 1000 joule 'whole house' protector might survive for
    well over 100 such surges.

    Notice that numbers are provided in this post. To disagree,
    another will have to provide better numbers. That is the
    problem with so many posts about MOV protectors. They provide
    no numbers - only parrot myths they have heard. Provide here
    even were the charts from MOV manufacturers. That is damning
    evidence that says joules are important.

    BTW, how does a protector fail? It degrades. No protector
    properly sized fails by vaporizing or burning. That failure
    mode is not even listed on those charts or by manufacturer
    data sheets. Vaporization must never happen to a properly
    sized protector. IOW notice how many plug-in protectors are
    not just undersized. They are grossly undersized - completely
    ineffective.

    Why did I mention an undersized 345 joules protector? Look
    at the joules claimed even on plug-in UPS protectors. It too
    is undersized. But then the manufacturer did not even claim
    to provide protection from the destructive type of surge. He
    only says enough so that those myth purveyors will make wild
    assumptions and will recommend that UPS as if it was an
    effective surge protector.

    Effective protector must not be close to transistors and far
    from earth ground. A minimally effective 'whole house'
    protector for residential AC electric is about 1000 joules and
    50,000 amps. It costs about $1 per protected appliance.
    Compare that to how much for the grossly overhyped plug-in
    protectors? To be sized equivalent, the plug-in protectors
    would be rated 3000 joules.

    Art wrote:
    > "sdlomi2" <sdlomi2spamfree@yahoo.com> wrote in message
    > news:10ft3a08crs71c2@corp.supernews.com...
    >> How much surge protection, in joules, does one actually need
    >> for home computing system, including all-in-one pscf-machine?
    >> Are certain brands preferable to others? TIA, s.
    >
    > There's an article in the latest (August) issue of PCWorld on
    > what they refer to as "PC Myths". One, in particular, deals
    > with surge suppressors and, according to PCWorld, refutes the
    > notion that a pricey surge protector affords more protection
    > that the cheapo models. The article contains a statement from
    > a presumed expert that the number of joules is *not* a reliable
    >indication of quality and all that's important is that the
    > device is UL 1449 rated. All this, of course, seems to fly in
    > the face of everything we've previously read or heard on this
    > subject. Here's the link to the article:
    > http://www.pcworld.com/news/article/0,aid,116572,pg,5,00.asp
    >
    > Art
  6. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    100 Joules ZnO varistors with clamping @ 1200 V in the input circuit breaker
    cabinet, with an excellent earth ground.
    Then 10 Joules ZnO varistors w/ clamping @ 275 V close to the computer to
    be protected.
    Those varistors shall be connected between mains wires together and between
    them and the earth ground.

    The telephone socket shall be protected close to the modem and the computer
    it is connected to, with 10 Joule ZnO varistors w/ clamping @ 200 to 275 V
    as well.

    ! ! ! Same earth ground as the computer, star connected with it (very
    important not to have separate earth wires on separate outlets). And, of
    course only one earth wire, the shortest and the straightest as possible.

    For the second level protection (close to the computer), it's more important
    to guarantee a very low common mode between main & telephone signals vs. the
    computer housing connected to the earth wire than to guarantee a very low
    earth resistance itself. The input cabinet protection does the job for that.

    In case of a cable connected network with distant computers it's far more
    tricky.


    "Art" <Anonymous@notanisp.com> a écrit dans le message news:
    dJmdnbz9bIQ4KmPdRVn-jQ@adelphia.com...
    > "sdlomi2" <sdlomi2spamfree@yahoo.com> wrote in message
    > news:10ft3a08crs71c2@corp.supernews.com...
    > > How much surge protection, in joules, does one actually need for
    home
    > > computing system, including all-in-one pscf-machine? Are certain
    brands
    > > preferable to others? TIA, s.
    >
    > There's an article in the latest (August) issue of PCWorld on what they
    > refer to as "PC Myths". One, in particular, deals with surge suppressors
    > and, according to PCWorld, refutes the notion that a pricey surge
    protector
    > affords more protection that the cheapo models. The article contains a
    > statement from a presumed expert that the number of joules is *not* a
    > reliable indication of quality and all that's important is that the device
    > is UL 1449 rated. All this, of course, seems to fly in the face of
    > everything we've previously read or heard on this subject. Here's the link
    > to the article:
    > http://www.pcworld.com/news/article/0,aid,116572,pg,5,00.asp
    >
    > Art
    >
    >
  7. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    On Wed, 21 Jul 2004 21:48:14 +0200, "Aldo Larrabiata"
    <zzz@zorglub.net> wrote:

    >The telephone socket shall be protected close to the modem and the computer
    >it is connected to, with 10 Joule ZnO varistors w/ clamping @ 200 to 275 V
    >as well.
    before them also 0,4A fast fuse is nice; I change them at least once
    a year, because they blow ...
    --
    Regards, SPAJKY ®
    & visit my site @ http://www.spajky.vze.com
    "Tualatin OC-ed / BX-Slot1 / inaudible setup!"
    E-mail AntiSpam: remove ##
  8. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    Cited is MOV protectors that are ineffective for too many
    reasons. First undersized. Second, too close to transistor
    and too far from earth ground. Third, MOVs typically have too
    much capacitance for phone lines. Fourth, the voltage levels
    are too low as even demanded by FCC and other standards.

    MOVs are shunt mode devices. They are not 'protection'.
    MOVs are 'protectors' that are only effective if making the
    'less than 10 foot' connection to 'protection'. Yes,
    'protector' and 'protection' are two difference components of
    a surge protection system. A protector that does not make the
    'less than 10 foot' connection from utility wire to earth
    ground does not provide effective protection. Real world
    surge protector manufacturers discuss this extensively.

    If protectors adjacent to phone were effective, then those
    protectors are already inside the phone. However telco
    already installs an effective protector for free and less than
    10 feet to the single point earth ground.

    A protection system is a building wide system - which is why
    system costs typically tens of times less money per protected
    appliance.

    Another also has a silly idea that fuses stop, block, or
    protect from surges. Fuses take milliseconds to blow. Surges
    complete their destructive work in microseconds. 300
    consecutive surges could destroy a modem 300 times before a
    fuse even though about blowing.

    Furthermore, if the fuse blew, then the surge would continue
    to conduct through plasma inside that fuse. This is why a
    fuse has a voltage rating - 32 volts or 250 volts. A surge of
    greater than 250 volts would simply continue conducting
    through the blown fuse. Again, numbers that demonstrate that
    fuse recommendation is not based upon basic electrical
    knowledge and the numbers.

    Fuse recommendation is bogus for just so many reasons. The
    fuse recommendation demonstrates how widespread myths are
    promoted about surge protection by the naive. Those with
    basic electronics training know the purpose of a fuse is to
    protect humans from dangers such as fire AFTER the appliance
    is damaged.

    Just as in that other post: numbers, manufacturer data, and
    basic engineering principles are provided. To challenge what
    is posted, that poster better have those numbers and cite
    industry professionals. No numbers is how junk scientists
    promote their myths.

    Spajky wrote:
    > On Wed, 21 Jul 2004 21:48:14 +0200, "Aldo Larrabiata"
    > <zzz@zorglub.net> wrote:
    >> The telephone socket shall be protected close to the modem and
    >> the computer it is connected to, with 10 Joule ZnO varistors
    >> w/ clamping @ 200 to 275 V as well.
    >
    > before them also 0,4A fast fuse is nice; I change them at
    > least once a year, because they blow ...
  9. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    maybe you should have searched more pertinent keywords like
    'surge protection'.......

    "sdlomi2" <sdlomi2spamfree@yahoo.com> wrote in message
    news:10ftad6rbns6h6a@corp.supernews.com...
    >
    > "JAD" <Kapasitor@coldmail.com> wrote in message
    > news:10ft8jr9pbt5k6d@corp.supernews.com...
    > > OMG here we go again.....................
    > >
    > > "sdlomi2" <sdlomi2spamfree@yahoo.com> wrote in message
    > > news:10ft3a08crs71c2@corp.supernews.com...
    > > > How much surge protection, in joules, does one actually need
    for
    > > home
    > > > computing system, including all-in-one pscf-machine? Are
    certain
    > > brands
    > > > preferable to others? TIA, s.
    > > >
    > > >
    > >
    > >
    > I sincerely apologize to you, Tad, if I somehow offended you by
    asking
    > this question. But, not knowing, and finding, by searching FIRST,
    not even
    > ONE response/post using the word "joule" in this entire newsgroup, I
    felt I
    > might utilize the group for its intended use. Felt sure there are
    > knowledgeable people who might agree to share info on this site.
    > Again, I'm sorry you felt the need to respond--esp. since I
    learned very
    > little from it.
    > Sincerely, s
    >
    >
  10. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    'joule'

    <Re: Are mains surge protectors needed in the UK? 7/14>

    you must be using one of those more sophisticated news readers

    I'm not OFFENDED , but you will have quite a read
    now..............carry on A1's


    "sdlomi2" <sdlomi2spamfree@yahoo.com> wrote in message
    news:10ftad6rbns6h6a@corp.supernews.com...
    >
    > "JAD" <Kapasitor@coldmail.com> wrote in message
    > news:10ft8jr9pbt5k6d@corp.supernews.com...
    > > OMG here we go again.....................
    > >
    > > "sdlomi2" <sdlomi2spamfree@yahoo.com> wrote in message
    > > news:10ft3a08crs71c2@corp.supernews.com...
    > > > How much surge protection, in joules, does one actually need
    for
    > > home
    > > > computing system, including all-in-one pscf-machine? Are
    certain
    > > brands
    > > > preferable to others? TIA, s.
    > > >
    > > >
    > >
    > >
    > I sincerely apologize to you, Tad, if I somehow offended you by
    asking
    > this question. But, not knowing, and finding, by searching FIRST,
    not even
    > ONE response/post using the word "joule" in this entire newsgroup, I
    felt I
    > might utilize the group for its intended use. Felt sure there are
    > knowledgeable people who might agree to share info on this site.
    > Again, I'm sorry you felt the need to respond--esp. since I
    learned very
    > little from it.
    > Sincerely, s
    >
    >
  11. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    On Wed, 21 Jul 2004 19:19:11 -0400, w_tom <w_tom1@hotmail.com> wrote:

    > Another also has a silly idea that fuses stop, block, or
    >protect from surges. Fuses take milliseconds to blow. Surges
    >complete their destructive work in microseconds. 300
    >consecutive surges could destroy a modem 300 times before a
    >fuse even though about blowing.
    >
    > Furthermore, if the fuse blew, then the surge would continue
    >to conduct through plasma inside that fuse. This is why a
    >fuse has a voltage rating - 32 volts or 250 volts. A surge of
    >greater than 250 volts would simply continue conducting
    >through the blown fuse. Again, numbers that demonstrate that
    >fuse recommendation is not based upon basic electrical
    >knowledge and the numbers.
    >
    > Fuse recommendation is bogus for just so many reasons. The
    >fuse recommendation demonstrates how widespread myths are
    >promoted about surge protection by the naive. Those with
    >basic electronics training know the purpose of a fuse is to
    >protect humans from dangers such as fire AFTER the appliance
    >is damaged.

    miss understood; my surge protector with built in RF filter & phone
    line protection had on tel.line side originally 2 fast .5A 250V fuses
    followed by 3 MOVs on the output for modem side.
    In last years few times saved my Supra modem .... thats a fact!
    (last time 3 weeks ago with a close lightning hit !!! - all my
    neighbors around had much much much more damage than I did!)

    ( & yes I know that everything is useless with Direct lightning hit!)
    --
    Regards, SPAJKY ®
    & visit my site @ http://www.spajky.vze.com
    "Tualatin OC-ed / BX-Slot1 / inaudible setup!"
    E-mail AntiSpam: remove ##
  12. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    The protector installed for free by the telephone company
    (properly earthed) had nothing to do with the protection?

    Surge protectors are installed for a direct strike to
    incoming wires. If nothing can provide direct strike
    protection, then your telephone company, connected to overhead
    wires everywhere in town, must disconnect their $multi-million
    switching computer during thunderstorms? 911 emergency
    response operators remove their headsets and leave the room
    during thunderstorms? Neither happens because surge
    protection, properly installed, protects from direct lightning
    strikes without damage. Damage so easily avoided as to be
    blamed on human failure.

    Direct strike protection is about earthing. Without that
    essential earthing, then nothing is going to stop, block, or
    absorb surges. Furthermore, modems are typically damaged by
    transients on AC mains - not from phone line. Again, many who
    said otherwise saw evidence but forgot how electricity works;
    therefore speculating erroneous conclusions.

    Details will not be provided since those details have been
    discussed extensively elsewhere. Fuses do not protect
    electronics. If those fuses blew, then surge had already
    passed through the electronics. Until you have completely
    understood the event (and it must be at the building level),
    then you don't know why those fuses blew. We know fuses don't
    protect from surges. The numbers are blunt. Surges occur in
    microseconds. Fuses take milliseconds to blow. Until one can
    explain that reality, then one cannot say a fuse protected
    electronics.

    Without learning about lightning protection concepts well
    proven since the 1930s, then one cannot say "everything is
    useless with Direct lightning hit". That statement flies
    contrary to what is proven by example in most every town every
    year.

    Spajky wrote:
    > miss understood; my surge protector with built in RF filter &
    > phone line protection had on tel.line side originally 2 fast
    > .5A 250V fuses followed by 3 MOVs on the output for modem side.
    > In last years few times saved my Supra modem .... thats a fact!
    > (last time 3 weeks ago with a close lightning hit !!! - all my
    > neighbors around had much much much more damage than I did!)
    >
    > ( & yes I know that everything is useless with Direct lightning hit!)
  13. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    Right !

    But obviously no fuse on the computer line ! ! !


    "Spajky" <Spajky##@volja.net> a écrit dans le message news:
    qtttf0dff5gdf167a3bs9tsjt3ot386qki@4ax.com...
    > On Wed, 21 Jul 2004 21:48:14 +0200, "Aldo Larrabiata"
    > <zzz@zorglub.net> wrote:
    >
    > >The telephone socket shall be protected close to the modem and the
    computer
    > >it is connected to, with 10 Joule ZnO varistors w/ clamping @ 200 to 275
    V
    > >as well.
    > before them also 0,4A fast fuse is nice; I change them at least once
    > a year, because they blow ...
    > --
    > Regards, SPAJKY ®
    > & visit my site @ http://www.spajky.vze.com
    > "Tualatin OC-ed / BX-Slot1 / inaudible setup!"
    > E-mail AntiSpam: remove ##
  14. Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

    > > Furthermore, if the fuse blew, then the surge would continue
    > >to conduct through plasma inside that fuse. This is why a
    > >fuse has a voltage rating - 32 volts or 250 volts. A surge of
    > >greater than 250 volts would simply continue conducting
    > >through the blown fuse.

    That's true with DC current because the arcing will stops when the current
    does.
    With the AC current of the mains, the arcing doesn't last more than 10 ms.
    The reason is that the sign of the current reverts twice a period.

    Some fuses contain silica. Its purpose is to lenghten the arcing path making
    it easier to break. Moreover those fuses withstand better the arcing
    phenomena without exploding messily.
    For electronic uses (mechanically non-protected) fuses and/or fuses
    potentially submitted to high short circuits currents, glass fuses are
    avoided to the profit of glass/silica filled ones. Big fuses (25 Amps and
    more) have a ceramic body filled with silica as well. When I say silica,
    it's in fact a powder made of several ingredients which formula is jealously
    kept confidential by the manufacturers.


    > >basic electronics training know the purpose of a fuse is to
    > >protect humans

    No, the purpose of a fuse is to protect the insulation of the wires of the
    electrical installation connected downstream because of overheating in case
    of short-circuit. A fuse is always placed upstream the line to be protected.

    A fuse is intended to withstand for one hour _without any failure_ 110% of
    its rated current.
    At 100% it must last forever up to the rated temperature.

    Then, the time a fuse needs to blow depends on its thermal constraint (I x I
    x t) I square T.
    There are slow and fast fuses.

    With an identical thermal constraint, a semiconductor will always protect
    the fuse because the semiconductor is faster.

    As an example: If you want to protect a 230V / 250 W dimmer, you shall use a
    fast 1.6 A rated fuse withstanding 15 Amp during 10 ms (cold inrush current
    in a bulb) and the associated triac shall be at least 20 Amp peak rated
    (nominally 5 A RMS). Big die inside a TO220 package !


    > line protection had on tel.line side originally 2 fast .5A 250V fuses
    > followed by 3 MOVs on the output for modem side.

    Correct.


    > ( & yes I know that everything is useless with Direct lightning hit!)

    Yes and no, an umbrella put on the hole in the roof may save of the rain
    what is placed underneath !
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