[TowerTalk] Fwd: Fwd: Fwd: Screw Anchor Experience

[Steve Maki]

On 6/22/2013 2:59 AM, K8RI wrote:

> On 6/22/2013 12:27 AM, Hans Hammarquist wrote:
>> I believe the screw anchor is good enough by itself to act grounding
>> rod. I, myself, did not put any grounding rods at the guy anchors but
>> I used nine (9) grounding rods around the foot of the tower. These rod
>> are not copper rods but galvanized steel. I also have galvanizes steel
>> rods holding the tower in place. I think I have enough grounding. I,
>> needless to say, do not have enough for a direct hit though. Who does?

> The guy anchor should not serve as a ground for any thing, so it should
> not need a ground rod either.
>
> The guy, if metal,should have an insulator near the anchor, preventing
> the anchor as serving as a ground.
>
> Several of us have stated the circuit consisting of ground, tower, guy,
> guy anchor, and ground must be broken with an insulator, preventing the
> round rod as serving as a battery that eats itself up by serving as one
> of the electrodes. If this is done there is no need for a sacrificial
> electrode.

According to Anchor Guard, an anchor even all by itself can act as a 
corrosion cell:

"Basic Anchor Support Design Example 1. Figure 6 shows the basic design 
of a typical anchor support. The anchor support has all the necessary 
elements of a corrosion cell. The shaft itself acts as both anode and 
cathode as well as the electrical path between the two. The concrete and 
soil act as dissimilar electrolytes. The soil has less oxygen just above 
the concrete anchorage and consequently, less resistivity. The 
electrical path is the shortest between the anode and the cathode at the 
same point as the oxygen deficient soil, thus the deteriorating action 
of corrosion is most strongly in effect in this area. Experience has 
shown that this is the area most likely to deteriorate and cause the 
tower to fail."

-Steve K8LX