"w_tom" wrote

Lets start by first adjusting the perspective.

You were going strong until you drove off the road and into the ditch right
he

Single point ground can be a single earth ground rod at one
of the building, or it can be accomplished by making earth
beneath equipotential. But it comes back to a basic concept.
No current flows if an incoming and outgoing path does not
exist. Goes right back to elementary school science that
defined electricity. First a complete circuit must exist
meaning that each component must have both an incoming and
outgoing path.

The concept of single point ground is make only one
connection so that both incoming and outgoing paths do not
exist. Some examples of how this is accomplished:

Best remove that whole paragraph from your lightning vocabulary and pretend
you never saw it before. It is completely incorrect and misleading to allude
that lack of a path or circuit will protect anything from lightning. The
opposite is true.

The bonding of all nearby electrically conductive objects is what makes them
equipotential, because current does not flow when there is no potential
between bonded equipments. Interrupting the "circuit" by failing to properly
bond will allow massive potentials and lightning will find several paths you
should have known about and others you never knew possible.

Creating "Equipotential" (bonding) and "Grounding" are two distinctly
seperate principles. Both are required in a system of lightning protection.
If there was one that was immensely more important than the other, it would
be the bonding. A well bonded system "could" survive direct lightning
strikes to the structure with no damage to the equipment even if there was
never a ground connection made (happens to airplannes frequenty). But no
ground system conceivable can allow an equipment room that is not properly
bonded to survive a strike. Applying the two principles of bonding and
grounding together (and surge protection), is what helps control all the
entrance and exit paths for lightning, and makes a lightning protection
"system".

Jack

A well bonded system means all those other potential
'outgoing' paths are connected to the same 'incoming' path.
IOW bonding converts all other possible electrical paths into
the same, common incoming path. If all circuit paths only
connect to the same 'incoming' path, then there is no outgoing
path necessary to conduct electricity.

This is also why equipotential grounding works. But this is
arguing semantics. Bottom line is the perspective of a
protected circuit. If all incoming paths are properly bonded
to a same point, then no outgoing path exists. No outgoing
path means no destructive electricity flow through that
circuit. Therefore no damage.

Jack Painter wrote:
You were going strong until you drove off the road and into the
ditch right he

Single point ground can be a single earth ground rod at one
of the building, or it can be accomplished by making earth
beneath equipotential. But it comes back to a basic concept.
No current flows if an incoming and outgoing path does not
exist. Goes right back to elementary school science that
defined electricity. First a complete circuit must exist
meaning that each component must have both an incoming and
outgoing path.

The concept of single point ground is make only one
connection so that both incoming and outgoing paths do not
exist. Some examples of how this is accomplished:

Best remove that whole paragraph from your lightning vocabulary and
pretend you never saw it before. It is completely incorrect and
misleading to allude that lack of a path or circuit will protect
anything from lightning. The opposite is true.

The bonding of all nearby electrically conductive objects is wha
makes them equipotential, because current does not flow when there
is no potential between bonded equipments. Interrupting the
"circuit" by failing to properly bond will allow massive potentials
and lightning will find several paths you should have known about
and others you never knew possible.

Creating "Equipotential" (bonding) and "Grounding" are two
distinctly seperate principles. Both are required in a system of
lightning protection. If there was one that was immensely more
important than the other, it would be the bonding. A well bonded
system "could" survive direct lightning strikes to the structure
with no damage to the equipment even if there was never a ground
connection made (happens to airplannes frequenty). But no ground
system conceivable can allow an equipment room that is not properly
bonded to survive a strike. Applying the two principles of bonding
and grounding together (and surge protection), is what helps
control all the entrance and exit paths for lightning, and makes a
lightning protection "system".

Jack

All about lightning and grounding at Polyphaser URL:
http://www.polyphaser.com/ppc_ptd_home.aspx


--
Lamont Cranston