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Surge protection, lightning, grounding, modems


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From: w_tom <w_tom1@hotmail.com>
Subject: Re: WinModems
Date: Wed, 29 Jan 2003 14:51:54 -0500
References: <b11h0b.mf5.ln@news.it.uc3m.es>
<b0gtfb$5qd$02$1@news.t-online.com> As demonstrated by high school science, one must understand both theory and experimental evidence to have knowledge. Have you built surge protectors, seen them work or fail, and learned the underlying theory? I have even repaired modems by replacing components on the PC board - to learn how surges damage modems. I learned the circuit paths used by surges through modems by replacing the defective parts. Your friend used surge protectors and still lost modems. Of course. Was the surge protector at the service entrance and connected short to central earth ground? If not, then the surge protector many even have contributed to his modem damage. Just because it is called a surge protector does not mean it provides surge protection. That assumption is called junk science.

  It is called 'whole house' surge protection.  Principles
were proven long before either you or I existed.  A surge
protector is only as effective as its earth ground - as even
Ben Franklin demonstrated in 1752.  To appreciate why surge
protectors work successfully, one must understand the
difference between impedance and resistance, AND must
understand why that concept is appropriate to surge
protection.  These are 1st year EE concepts.

  Cited previously is a discussion in newsgroup misc.rural. 
Nothing technically advanced.  But if simple concepts are not
understood, then the reader does not have sufficient knowledge
to know even what a surge protector does.  Demonstrated is why
plug-in surge protectors are not effective (safety ground wire
does or doesn't exist) and why a surge protector must connect
less than 10 foot to central earth ground.

  A tech support person should be familiar with why surge
damage happens. Figure from an industry professional shows how
effective surge protection is installed - the essential single
point ground for each structure.  Destructive surges can even
enter on underground wires.  Notice no plug-in surge
protectors:
  
http://www.erico.com/erico_public/pdf/fep/TechNotes/Tncr002.pdf 

  A benchmark in surge protection is Polyphaser.  Tech support
should know that name.  Polyphaser's application notes are
considered legendary by industry professionals.  What do they
discuss? Earthing, because surge protection is about earthing
a surge - not about surge protectors:
   http://www.polyphaser.com/ppc_technical.asp

http://www.telebyteusa.com/primer/ch6.htm
> Section 6.4:
> Conceptually, lightning protection devices are switches to 
> ground. Once a threatening surge is detected, a lightning 
> protection device grounds the incoming signal connection point 
> of the equipment being protected. Thus, redirecting the 
> threatening surge on a path-of-least resistance (impedance) 
> to ground where it is absorbed.

http://www.ipclp.com/html/aud_ho_faq.html
> A properly installed lightning protection system intercepts 
> the lightning bolt between cloud and earth and harmlessly 
> conducts it to ground without damage.
> Yes, in addition to the lightning protection system consisting 
> of air terminals, conductor cables, clamps, fasteners, 10 foot 
> grounds, etc., a secondary lightning suppressor is installed 
> on your electric service entrance panel to prevent current 
> fluctuations (called lightning surges) during a thunderstorm. 



  That secondary lightning suppressor is the 'whole house'
surge protector. 

  Does the surge enter on phone line, destroy a modem, then
stop?  Of course not.  Surges are electricity.  No surge
damage occurs if a complete circuit does not exist.  An
incoming and outgoing path must exist through that modem to
have surge damage.  One does not have a clue how a surge
damaged something until one first defines both that incoming
(from cloud) and outgoing (to earth) circuit path.  This was
defined in the above cited discussions you were expected to
read in misc.rural. 

  Industry professionals learn underlying principles which is
why both internal and external modems are exposed to same
surge damage.

  Again, you don't have the real world experience.  You have
heard about 15 symptoms.  But did you follow the complete
circuit - incoming and outgoing through the building?  Did you
replace damaged components to make the modem work?  Does you
experience also demonstrate that destructive surges occur
typically once every eight years?

  Did you first learn from IEEE papers that demonstrate that
outlet safety ground wire, if used for surge protection, would
induce surges on all other household wires?  Read that
sentence again.  That ground wire bundled with other household
wires would induce surges throughout the building if a surge
was using that safety ground wire.  Again, another reason why
a surge protector to earth ground wire must be less than 10
feet - and other essential fundamentals defined in those
misc.rural newsgroup discussions.

  Those posts in misc.rural were not read which explains so
little knowledge about surge damage.  Those who have both
learned theory and have extensive experience know why 'whole
house' surge protectors with a short connection to earth
ground are critical.  Don't response yet.  First learn how
much there is to know about surge protection AND how
ineffective plug-in UPSes and surge protectors really are. You
have many hours of reading in those two discussion in
misc.rural. Many industry sources cited. The importance of
this sentence will then be important:  a surge protector is
only as effective as its earth ground.


Kirk Strauser wrote:
> At 2003-01-29T03:32:52Z, w_tom <w_tom1@hotmail.com> writes:
> 
>> This poster demonstrates a lack of real world experience.
> 
> By this, you mean "you"?
> 
> Look, I'm not making this stuff up.  As I said earlier, I've personally
> talked to 15-20 people whose computers were burnt to a crisp via lightning
> into an internal modem.  I'm certain that not every single one of them lived
> in old houses with ancient wiring.  A good friend, for instance, lived in a
> 10-year-old home, used surge protectors, and still lost hardware.
> 
> I'm sure that you know something about the subject, but I've seen this
> happen first-hand, and I'm not particularly interested in someone telling me
> that it's either impossible or extremely unlikely.
> 
> To re-iterate, when I worked in tech support, it was well-accepted that a
> thunderstorm *would* result in one or two callers who were online during the
> storm, and now can't boot their computers.  Guaranteed, every time.
 


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All I can say is that Taking advice on Lightning protection from w_tom is like asking blind freddy for advice on Colour
w_tom has absolutely no idea about Lightning Protection, Power Distribution or Basic electrical Theory.

Kirk Strauser on the other hand is correct Using an Internal Modem in a PC is like pleading with Thor to blow the living S..t out of your PC in the Next Thunderstorm.

You see by far the most common path for Lightning is in via the phone Line, through your modem and out to the Earth provided by the AC Mains - Not the other way round as w_tom claims. Contrary to w_toms bizarre belief Phone lines are not actually earthed anywhere whereas AC Mains is.

As for w_toms 1KJ Mov these generally last about 20nS in a Near or direct Lightning strike and after that the race is on to destroy your Modem, PC and anything else in the way.

THE ONLY PROTECTION YOU CAN PROVIDE DURING A THUNDERSTORM IS TO UNPLUG YOUR MODEM AND PC. running the PC on AC Mains qlone is a calculated risk and although I cannot recall offhand any damage that came in Via AC mains alone from Lightning I will concede that it is possible.





Kerio Samepage


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