[TowerTalk] Protecting Buried Guy Anchors

[Jim Thomson]

Date: Wed, 13 Oct 2010 22:08:11 +0000
From: Don Moman VE6JY <ve6jy.1 at gmail.com>
Subject: Re: [TowerTalk] Protecting Buried Guy Anchors

If you have insulated guy wires, no galvanic current can flow. If not:
insulate them....  1 amp for 1 year consumes 20 lbs of anchor - so even a
few milliamps over time from a small earth potential difference can weaken
your anchor. Protecting the anchor rod from the earth with tar/pitch
compound can't hurt either.

73 Don
VE6JY

On Wed, Oct 13, 2010 at 9:35 PM, Mark Robinson <markrob at mindspring.com>wrote:

> I have installed the standard Rohn GAC303 guys anchors into buried concrete
> per the Rohn drawings.
>
> I was talking to a tower installer who says that he has seen these buried
> guy anchors eaten away in only a few years.
 I think that I am OK since I have pulled 8 foot copper ground rods that
> have
> been in the ground here for several years and they came out shiny and
> bright.


............................................................................................................................................

>
 Interestingly enough, I will be adding cathodic protection to my 145 foot Rohn 45 tower this 
weekend even though after 9 years, there is no evidence of anchor corrosion (primarily because
 my guys are insulated and not grounded at the anchor points).

  GL es 73,

  Jeff, W3KL

##  what's wrong with grnding the guy wires themselves ?   You see that in the Rohn catalogs. 
IF EHS used, and broken up with egg insulator's, there should be no current flow.   There was 
something in the latest   EIA-222-rev G spec  abt  grnd rods for guy wires. I think it was  that
copper rods could no longer be used,  because of disimilar  metals, or the grnd wire  from the
grnd rod  to the galvanized guys  could not be  copper.  

##  it all depends if your soil is alkaline..or acidic.  Around here, 8' copper grnd rods last forever,
and ditto with copper water pipes coming into homes.  Galvanized anything  that is in direct soil
contact just eats itself.  A friend back in 1980, had a rental place, and buried the bottom 2'  of his
tower [angle legs]  into dirt.  Then guyed the tower, along with the house bracket.   He took it all down
in 1990....and there was almost  nothing left of the tower that was buried in the dirt !   Apparently, if using
galvanized GAC-XXX  rods in buried concrete, the portion of the GAC-XXX  rod  that comes up at an
angle is all in direct contact with the soil.  That  portion is supposed to be  covered with roofing tar pitch
1st, [ let harden].. then  installed in the grnd.   Having said that, telco's and pwr co's  use thousands of 
buried rods in the grnd, [AB Chance type screw in anchors, installed with a Kelly Bar]   and  they appear to 
hold up  for decades.  They also use at least one egg on each guy wire too. 

Jim   VE7RF