"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