Re: Panel Grounding vs. Lightning Rod Grounding

On Sep 30, 11:10ï¿½am, "Doug" <n...@home.com> wrote:
> "w_tom" <w_t...@usa.net> wrote in message
>
> news:a50945f9-949a-4dfc-9e3c-5e860b5d0938@e53g2000hsa.googlegroups.com...
>
>
>
>
>
> > On Sep 30, 1:23 am, David <inva...@socrates.edu> wrote:
> >> Tom, would you happen to have a link to the 1990 code -- where it
> >> addresses
> >> the present topic of lightning grounding?
>
> > ï¿½Code does not address lightning grounding except where
lightni
ng
> > might harm a human. ï¿½Code is about human safety. (For
example, 
a TV
> > ariel and lightning rods have a dedicated earth ground defined by
> > code.) ï¿½Code must be met and then exceeded for appliance
protec
tion.
>
> > ï¿½Code does require earthing of everything to a common
point. 
ï¿½Code
> > requires connections to earth ground to be less than 20 feet.
ï¿½
And
> > code required a dedicated earth ground - water pipe is no long
> > sufficient for earthing. ï¿½An electrician will meet code
require
ments.
> > But protection means code is also exceeded.
>
> > ï¿½For lightning protection, wire gauge is not important.
ï¿
½Wire length,
> > no splices, not inside conduit, separated from other wires, and no
> > sharp wire bends are more critical. ï¿½Code does not
address thes
e
> > 'also' issues. ï¿½ IOW a ground wire from breaker box to
earth mu
st not
> > go over the foundation and down to earth. ï¿½That is too
long, to
o many
> > sharp bends, and not separated from other wires.
ï¿½Earthing must
be
> > routed through the foundation and down to earth for better surge
> > protection. ï¿½Reason why is wire impedance.
>
> > ï¿½A utility demonstrates how to kludge a solution when the
build
ing
> > was constructed wrong:
> > ï¿½http://www.cinergy.com/surge/ttip08.htm
> > This also upgrades earthing to 'exceed' what only met code.
>
> > ï¿½One underlying concept is impedance.
ï¿½Whereas a 50' ro
mex wire to
> > breaker box would be well under 0.1 ohms resistance to AC electricity
> > - that same wire may be 120 ohm impedance to a surge.
ï¿½Code is 
mostly
> > about wire resistance. ï¿½Electronic protection requires
low wire
> > impedance which is why grounding must exceed the 1990 code.
ï¿½Ma
ny
> > mistakenly assumed their panel was grounded by assuming wire
> > "resistance". They did not grasp a more important concept - wire
> > "impedance".
>
> > ï¿½Experience without underlying knowledge teaches nothing.
ï
¿½Experience
> > is only educational when concepts such as wire impedance are
> > understood. ï¿½So many 'knew' grounding did nothing by
forgetting
to
> > learn fundamental concepts such as wire impedance. ï¿½Their
'less
> > experience' ï¿½combined with no fundamental knowledge
taught them
> > nothing.
>
> You wouldn't happen to know anything about Belgian wireless alarm systems
> would you?
>
> Doug-

Oh crap ........ now ya did it!
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