[Elecraft] Lightning Protection articles

[Don Wilhelm]

Joe,

Details on *my* perimeter ring -- I put mine in while backfilling around 
the foundation, used #4 wire and placed it 6 to 12 inches under the 
final grade.  It is located quite near the foundation - from zero to 12 
inches.  There is a driven 8 ft. ground rod at every corner and any 
other place where the wire must make a turn - in my case, that is  9 
ground rods.  Rather than CAD-welding and burying the ends of the rods 
and wire, I choose to clamp mine using clamps above the ground, so at 
each ground rod location, the wire comes upward in a smooth arc to clamp 
above the  ground.  I can go around the house and check each clamp each 
spring and fall - just try to snug it down a bit with a wrench, if it 
moves it needed tightening.  That takes only a short time for that 
maintenance.  Every conductor exiting the building is tied to this 
perimeter wire, but in my case there are none other than the utilities - 
electric and telephone - all plumbing is PVC or CPVC.

There is nothing wrong with a perimeter wire further away from the 
foundation, that is just the way I did it.  I had no sidewalks to 
contend with because they had not yet been built.  Each installation 
will be different, and the installer may have to be creative.
If I had sidewalks or paved driveways to deal with, I would look at 
methods like running the wire through an expansion joint area, or boring 
through under the concrete.  I believe the continuity is more important 
than the depth of the wire, but that is just my guess, I have no data.

As pointed out in the QST articles - do the best you can and know the 
shortcomings of your installation.  That knowledge *should* be able to 
tell you how much you can trust it during a lightning event and how far 
you should stay away from the equipment during a lightning event.  
Unless you have an installation using much larger conductors than I have 
used, and bring all conductors into the operating area through a single 
"grounding window", then do not even think about operating through a 
lightning storm as commercial broadcast stations do.  If I had 00 wire 
for the perimeter wire and the ground connections and a continuous sheet 
of copper under the floor to keep everything at the same potential, I 
might consider operating through a storm, but I do not have that kind of 
installation - I just believe mine is better than many.

The answer to part of what started this discussion is still unchanged, 
all ground rods should be connected to the utility entry ground - that 
is a part of the AC grounding scheme and is to keep all persons safe in 
case of an electrical fault.  Lightning protection is a different 
animal, but in the case where we hams tend to drive additional ground 
rods, the two can be (but not necessarily) considered together.  Neither 
of these grounding systems should be considered as an RF ground - that 
is another subject entirely.

73,
Don W3FPR

Joe Planisky wrote:
> Hi Don,
>
> The KB2UYT articles from 2002 mentions a perimeter ring, but gives no  
> real details as to the construction and installation of the ring.  An  
> article by KD7PEI in the 8/2008 QST gives more details, but still  
> fails to answer some questions such as:
>
> How far away from the building foundation can the ring be?  Obviously  
> closer means less material needed, but can it be TOO close?  Can it be  
> too far?
>
> How do you deal with concrete sidewalks, concrete driveways, stone  
> patios, or other obstacles that prevent you from placing the ring  
> close to the foundation?  (KB2UYT does say that "A perimeter ground  
> that only goes three-quarters or half-way around the house is better  
> than no perimeter ground at all."  But would it be better to get a  
> complete ring with parts of it 20' away from the foundation, or a  
> partial ring 3' away?)
>
> Is there a recommended vertical separation between the ring conductor  
> and other underground pipes and wires?
>
> If you have time and are so inclined, could you perhaps tell us more  
> about the ring you installed, the materials you used, and how you went  
> about the installation?
>   
>