Jim Lux wrote:
w_tom wrote:

On Nov 8, 5:49 pm, scooterspal wrote:

At the time I looked into my needs I was directed to read the NEC
codebook... articles 800, 810, 820 and 830 that deal with communications
wiring.



NEC is about wiring for human safety. However that ground wire is
also installed for lightning protection - from a direct strike. Those
who fail to first learn numbers will post only their feelings. That 6
AWG is sufficient to earth a direct lightning strike and still remain
intact.

... consider that a bare 18 AWG (1 mm diameter) copper wire, in
air, normally will conduct at least 10 amperes safely, with very low
self-heating temperature rise. If the current slowly rises, the
temperature will increase until the melting temperature of 1065 C
(1950 F) is achieved at about 83 A. This same temperature could
be reached "instantly" by an 8x20 s pulse at a current of 61 kA.



Above numbers are from the front page of a professional engineering
publication (Electrical Engineering Times) of 1 Oct 2007. That 6
AWG can be expected to conduct 200,000 amps which is ten times more
than current from the typically lightning bolt.


http://www.planetanalog.com/features...leID=201807127

note that the author also speaks about the mechanical force issues with
the transient current. (And cites my website for lightning data, which
is kind of cool)..

Jim