Re: why ground an alarm panel.

[w_tom <w_tom1@xxxxxxxxxxx>]

  Many observe a tree damaged by lightning - then assume a
lightning strike is some massive energy.  IOW observations
were not tempered with comprehension of underlying concept and
the numbers.  We all were taught how and why to do that in
junior high school science.

  Well over 95% of trees struck suffer no appreciable damage.
When observers ignored that other 95+% data, then conclusions
were only what they wanted; not conclusions based in reality.
(BTW this is the same technical mistake that hyped child
leukemia from power lines.)

  Same misapplied reasoning is also found in comments such as:
> I've seen way more blown-up panels that were "grounded"
> than not.

  First, all panels are grounded.  Some simply are not
grounding sufficiently - even for human safety.  Why is a
wooden tree a conductor of electricity?  Tree branches are
grounded.   More 'resistive' grounding causes a higher energy
dissipation on that panel - and in that tree.  Therefore what
would be nearly zero power discharge is now and significantly
higher power discharge in a panel.

   Did you see all panels that suffered no damage from direct
transients?  IOW were your observations complete?  Or did you
only observe panels that had damage - ignore those other
panels that were better grounded and therefore had no
damage?   A classic example of observations using 'selective
data sampling'.  Panels that were sufficiently earthed also
suffered from transients - yet had no damage.  Not just
grounded - earthed.  Others that were not sufficiently earthed
(and yet may have been grounded), instead, suffered damage.
Only the last group appears in your observations - a violation
of principles taught in junior high school science.

  Yes improper grounding can contribute to damage which is why
an installer need understand the 'whys' behind terms such as:
'single point earth ground, 'less than 10 feet', 'common
service entrance', 'earthing wire separated from those wires',
and 'no sharp bends, no splices, not inside conduit'.

  One must demonstrated a comprehension of the difference
between grounding and earthing; impedance and resistance;
materials such a concrete and linoleum tile that are
electrically conductive.  Without such knowledge, then many
make assumptions only on what was observed - making 180 degree
erroneous declarations.  It's equivalent to learning from the
Daily News or Fox News;  therefore knowing Saddam had WMDs.
Those who read details - the underlying concepts - read what
the advance physics labs were saying; came to a completely
different conclusion.    A famous expression:  the devil is in
the details. That means learning underlying concepts.

  I see this often by those who did not comprehend or
completely forget what was taught in elementary school about
Ben Franklin's lightning rods and about how electricity
works.  They hype speculation that a lightning strike is a
high energy event, that lightning crashes upon a panel like
waves on a beach, and that grounding a panel causes panel
damage.  All three are myths.

  Another example.  What is legally required in grounding
verses what is technically superior or recommended are two
different things.  This reply was false:
> In this case the two are the same.

  We still do not wire dwellings as if the transistor exists -
even though wiring meets all code.   How can this be if code
legal requirements always result in technically superior
earthing - as you have stated?   Legal requirements for
building wiring make no effort to protect transistors.  Nor
should it according to objective of those codes.  Another
underlying concept - the purpose of those codes.

  Why code legal verses necessary grounding are not
equivalent?  Again, demonstrated by differences between low
resistance and low impedance.  One must first comprehend
underlying concepts.  Understanding those underlying concepts
makes this statement obvious:
>  This for electrical reasons such as wire impedance and
> what that safety ground wire is bundled with.

  What RLB describes is how things were done decades before
WWII where damage was not acceptable.  Although we still don't
wire new buildings as if the transistor exists, a solution is
still easily adapted - in most locations.

  Not grounding a panel can mean a panel is grounded by
inferior methods - for same reason why a wooden church steeple
is 'grounded'.  Why is the church steeple damaged by
lightning?  Inferior grounding causes more energy dissipation
and increased damage.  Sufficient grounding is required for
transistor protection.

"G. Morgan" wrote:
> On Sun, 18 Dec 2005 16:52:06 -0500, w_tom <w_tom1@xxxxxxxxxxx> wrote:
>>   What is legally required verses what is technically superior
>> or recommended are two different things.
>
> Absolutely.  In this case the two are the same.  In my opinion,
> NOT grounding a panel is "technically superior",  it's also not
> required by law.
>
> That saves the brake system wear and tear, yes, grounding a
> burg. panel actually detracts from the system's performance
> and longevity. I've seen way more blown-up panels that were
> "grounded" than not.
> ...
>
> What RLB described works great on paper and in theory, however,
> actually putting that scenario into practice is not feasable
> in 99% of installations.
>...
>
>> This for electrical reasons such as wire impedance and
>> what that safety ground wire is bundled with.
>
> Huh?