My $0.02:
I like the idea of bonding all the electrodes with direct buried bare copper. I
always do it, typically with #4. I would use #2 if it were not so much more
expensive. These are residential jobs. If I had large job, like the subject of
this thread, no problem with the #2.

If you only have equipment grounds, above grade, between electrodes, my
understanding is, energy from lightning will flow through those conductors
through and over whatever equipment is in it's path, because of the difference
in ground potential between electrodes. This is undesirable, to say the least. 

Ray, I subscribe to the loop theory as well, but I think it is only a problem
when the loop is all above grade. When half of the loop is in direct soil
contact, with big bare copper connecting multiple electrodes, the lightning
energy is dissipated in the earth before it does damage.

I have in this forum, previously made the case to consider the buried electrode
bonding conductors, as also serving as the required equipment grounding
conductors, since Article 250 allows DC equipment grounds to be run separately
from the circuit conductors. This eliminates the loop. However, Article 690 does
require them to be run with the circuit conductors. Bottom line, run both, don't
worry about the loop which is created.

Cadwelding is great stuff, and fun, like the 4th of July kind of fun. Tinning?
I've never seen it used on buried, bare conductors, though an internet search
show it's available. It is certainly not necessary to have tinned wire to make a
bomber cadwelded connection. 

Dick Ratico
Solarwind Electric


--- You wrote:
It all depends on how its done. If each electrode is attached to the next
electrode by the #2 and Cadweld directly, and also connected through the
required EGC, then there is a loop. Once you have the loop, the low resistance
#2 cable only increases its ability to generate current from an electromagnetic
field (created by a nearby lightning strike).
Cad welding is fine, tinned #2 is fine, but connect the rods through the EGC,
not twice. The only time you would want to connect rods directly to each other,
is if they are all tied to the system at only one point (ie, 3 rods attached in
a line to each other, last one is then connected up to the system)

R. Walters
ray@solarray.com
Solar Engineer

> I suggest that "lightning loops" are therefore a non-issue in Phil's scenario.
> 
> Jolliness,
> 
> Mick Abraham, Proprietor


