[TowerTalk] Grounding connection to tower legs

[Jim Thomson]

Date: Tue, 17 Oct 2017 07:29:22 -0700
From: Grant Saviers <grants2 at pacbell.net>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Fwd: Grounding connection to tower legs

<One more alternative is to use a DX Eng saddle clamp and extend the 
saddle backing plate far enough to use two hole lugs.  I made the 
backing plate out of 1/4 x 1-1/2" 6061 and wide enough for two lugs each 
side.  One clamp on each leg with 2 or 3  #6 or #2 wires to pairs of 
buried 8' rods Cadwelded.  I put some contact goop in the saddle area 
where it contacts the tower.  2" saddles for Rohn 65 are a very close 
fit.  A few dollars cheaper than the Rohn similar idea, and uses two 
hole lugs.  Aluminum against zinc is pretty benign electrochemically.

Grant KZ1W

##  Excellent idea !   DX eng  makes both saddle clamps and also the
heavier assy, that is a 1 inch wide solid aluminum saddle, one solid al
saddle on each side of the tubing in question.  They make em all the way from
small od  up to 2 inch  od.  The regular saddle clamps with the single, solid al
saddle go from tiny stuff...up to  4 inch od.    Then just use a wider hb al backing plate,
and punch /drill  2 holes in it for the mating U bolt..and 2 more holes for the mating 
2 hole compression clamp assy.   I would fabricate the  hb backing plate so the compression
clamp ends up in the vert plane.  

##  use the correct die, and compress ur  2 gauge stranded cu  in the 2 hole compression lug.
Use insulated 2 gauge cu,  Then cadweld  at the top of the 8ft  ground rod.  I think  current
eia –222 specs state that  TWO legs of the tower require grounding.   I do all 3 legs. 
Tops of each ground rod are below ground level, so only the 2 gauge wire is seen coming out
of the grass. 

##  2 gauge, stranded  cu, and insulated between tower legs and cadwelded ground rod
is placed inside that split loom stuff u see in home depot electrical dept.   Thats easy to
install either b4..or after the fact.    Then its all bomb proof. 

##  Only place I saw cu strap used was at the telco, if they had a rooftop tower, like a small one,
not very tall, with 1-2 microwave dishes on it.   Cu strap was 3 inch wide by at least .125 thick.
It went over the side of the flat roof..and down to ground level.  Then tied into the ground buss
system that encircled the building..which also contained the switching equipment, microwave gear, dsl stuff,
and everything else in a typ office.    Typ 10 ft rods  jack hammered in  every  10 ft. around the perimeter
of the building.  I dont know how the myriad of rods were connected.   Winter temps would hit –17 deg C. 
They need to be below the frost line.   But thats a different application, with different specs.  Had to be 
2 ohms or less...even in winter.   Nobody gets lightning in sub freezing wx, so that is a moot point.  

Jim  VE7RF