On Thu, 15 Jul 2010 18:54:08 -0700 (PDT), Tom Horne
wrote:

On Jul 13, 10:52*am, John Ferrell wrote:
I don't remember the sources but I have concluded that the Grounding
wire should be no smaller than #6.

*More than 8 feet of ground rod is of little consequence.

All ground rods should be tied together. Don't put your house between
two electrodes!

The ground rods are better directly under the structure that they are
protecting.

The system does not absorb massive high energy strikes. It starts
bleeding off the energy before the strike builds and thus minmiizes
the effect.

Home improvement stores sell #6 wire, ground rods and connectors.


John Ferrell W8CCW

John
Would you mind sharing what you base that advise on? Much of it
appears contrary to NIST guidance on protective grounding and current
industry practice.

Parts come from the code books,
some from experience and
some from observation.

The #6 wire is out of the code book. Reason and observation leads to
the conclusion that whatever you use there is the possibility of a
lightning strike that can vaporize it. That also supports the notion
that the charge must be bled off over time (seconds?) rather than
shunted to ground instantaneously. In a moment of lapsed judgment I
installed a ground rod for an invisible dog fence on the opposite side
of the house from the electric service ground. I also allowed the
TV-Internet cable ground a few feet away. Lightning strikes carbonize
cable coax connectors. Dog fence controller factory repair is $40 per
event. After much consideration I ran a #6 wire between the power
service ground and the rods for the dog fence and cable ground rods.
Much thought was given to this because that route involved putting a
conductive path along the floor joists just beneath my bed! I
considered the fact that copper plumbing is routinely routed without
concern wherever it is needed. No more service calls to the cable
company, no more repairs needed for the dog fence controller!

I have concluded that if more than 8 foot ground rods were required
for effect or code, the supply houses would be selling them. I cannot
argue with redundancy though. THERE IS A POTENTIAL PROBLEM WITH GROUND
RODS THAT ARE NOT BONDED WITH AT LEAST #6 WIRE! Common sense dictates
that protective system be continuously bled to a common level rather
than allowed to build up a differential charge.

My observations have led me to the notion that the frail little #6
wire does not provide the path for a direct strike. It only suggest a
route for the strike. A straight direct route is more likely to be
followed to ground than a longer twisted route. Lightning is a "boss
force". It can and will ionize its own path in a seemingly whimsical
manner. A spin-off cable loop has been popular for antenna entry
points for many years. This is one of those considerations that may
not do anything but it cannot hurt either!

Whatever you do it must:
Meet code, follow the law
Satisfy the Insurance company, don't give them room to wiggle out of a
claim!
Enhance safety
Protect your property.

In spite of all the precautions and preparations that you take you can
only reduce your exposure to the natural forces in life! My dog Shadow
(a black Labrador Retriever) endorses this by retreating to the Master
Bathroom during storm conditions. Midnight, (Shadows Cat) concurs by
hiding in the basement workshop under those same conditions. I
disconnect all ham radio antennas.

At this time I seem to have my problems at bay... but I also have
professionally installed lightning rods on the house.

John Ferrell W8CCW