In the discussion of the ground connection, a mix of guys commented or sent
pics of round conductors where others are using strap. The general comment
was that strap is better which I think means lower R & L for the run.
At the outset I was planning to use 3-gauge stranded insulated wire which I
have a lot of on hand. Wire would run from the tower leg clamp, over to the
edge of the concrete and then down to a copper ring bus where the individual
runners to the rest in-ground stuff was.
But for the conductor run from tower leg to ground system I am wondering
what width of strap would be better than the 3 gauge stranded wire. While I
realize that wider is better on the strap width, I wonder what width of
strap would approximate the 3-gauge wire?
73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie
-----Original Message-----
From: Clay Autery
Sent: Tuesday, October 17, 2017 7:32 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Fwd: Grounding connection to tower legs
On 10/16/2017 6:18 PM, jimlux wrote:
On 10/16/17 3:44 PM, Clay Autery wrote:
Just off the cuff, I think this would be overkill for *lightning
protection*, which is why you don't see this approach in the usual
commercial radio installation handbooks (e.g. R56)
you don't worry so much about low resistance or contact area - if it's
reasonably close, the lightning current will arc from one to the other and
a high current spark is VERY low impedance.
And with a long strap, if it does arc underneath, you've got somewhere for
pressure to build up.
What *is* important is mechanical strength - as Jim K9YC pointed out,
Well... For me? When I have many thousands of dollars in equipment at
risk, there is no such thing as "overkill". :)
Anything I can do to pump as much of the strike into the ground prior to
entry into the shack, and thence to reduce the step potential, I will
do. :)
It doesn't take that much "extra" to do a job right.
Who said anything about a "long strap"? I was responding to the man's
question about the clamp...
But since you bring it up.... yes... a strap as wide as I can make
work, AND as short as possible and of sufficient mechanical strength to
stand up to the forces imparted. Apologize... I assumed that those were
givens. <big smile>
73,
______________________
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|