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Tower Grounding Wire Size

To: <towertalk@contesting.com>
Subject: Tower Grounding Wire Size
From: robrk@fyi.net (Bob Morris K2RK)
Date: Sat, 04 Jan 1997 01:48:56 -0800
Wendell - W5FL wrote:
> 
> I bought and read the polyphaser book.  I am installing a 64 foot Rohn 45 
> Foldover tower.
> 
> Tomorrow I will weld the rebar cage for the Rohn 45 Tower section base and 
> weld 6 12 inch pieces to the 4 inch dia pipe guy wire anchors.  I plan to 
> weld or braze (whichever works) all the ground wires and radials to the rebar 
> and guy wire anchors.
> 
> Question 1:  How do you weld #6 copper wire to ugly old rebar?
> 
> I am planning to use #6 copper ground wire for all radials for lightning 
> protection.  Two 32 foot radials to each of the 4 guy anchor posts and two 65 
> foot radials to the tower rebar cage (ufer ground) and tie to one tower leg.  
> How should I tie the tower leg, the ground rod, and the rebar cage together?  
> Where should the #6 that runs 100 foot to the ham shack entrance panel tie to 
> the tower?  All the radials will run away from the house.  Polyphaser seemed 
> to indicate that you also needed to co
> 
> Question 2:  Is #6 awg solid copper ($0.20/ft) wire ok for the radial 
> grounding system.
> 
> It meets NEC codes and the Inductance decrease for #4 awg ($0.30/ft) is 
> negligible.  Polyphaser says #24 awg will fuse with a lightning strike, but 
> no where could I ever find a minimum wire size that will not fuse.  Since 
> this is a guyed tower, I at least get the benefit of a strike being split 10 
> ways (Tower, 4 guy wires, 3 feedlines, and two control cables).  How 
> conforting that oly 50% of the lightning energy will come in your house if 
> you can't strip it off of the coaxes and control cables!!
> 
> Ground Rods:  I have one sunk 8 feet in solid rock under the tower, and each 
> of the guy pipes are sunk 5 1/2 feet in the ground.  Beyond that I see no 
> further need for ground rods since they cannot be driven more than 2 to 3 
> feet under the surface horizontally (solid rock is 2 - 3 foot down)and they 
> cost $10 each (same as 50 feet of #6 awg copper ground wire).
> 
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'Welding" gound wires......At a REAL GOOD electric supply store, ask
for "Cadweld" wigits. Ceramic forms with a powder mixture. Form is 
place over a ground rod, wires put in side holes, powder dumped in,
and light with a torch. Makes a brass looking "weld". Many different
types of forms...for rods, one,two, three wire holes etc....
Maybe get a catalog....Cadweld.... Erico Prouducts Inc. Cleveland Oh.
GL

ps - ground your guy anchors, per the Rohn pictures....Some say don't
tie the rebar,inside the cement, to the ground system ?

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