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?
Hans - N2JFS
-----Original Message-----
From: Mark Robinson <markrob@mindspring.com>
To: Hans Hammarquist <hanslg@aol.com>
Sent: Thu, Jun 20, 2013 9:03 pm
Subject: Re: [TowerTalk] Fwd: Fwd: Screw Anchor Experience
Do you think I should pull the copper rods and install galvanized steel
ground rods instead?
Mark N1UK
----- Original Message -----
From: "Hans Hammarquist" <hanslg@aol.com>
To: <towertalk@contesting.com>
Sent: Thursday, 20 June, 2013 6:09 PM
Subject: [TowerTalk] Fwd: Fwd: Screw Anchor Experience
> To connect an anchor to a copper ground rod is an absolute no-no. That
> will "eat" the anchor in no time.
>
>
> Old wisdom (my grandfather, that was a blacksmith) to me to use a lead
> washer to minimize electrolytic corrosion. I put small pieces of
> insulators between the anchor rods and the turnbuckles to interrupt
> possible current. Could not harm, I believe.
>
>
> Hans - N2JFS
>
>
>
> -----Original Message-----
> From: Patrick Greenlee <patrick_g@windstream.net>
> To: towertalk <towertalk@contesting.com>
> Sent: Thu, Jun 20, 2013 5:55 pm
> Subject: Re: [TowerTalk] Fwd: Screw Anchor Experience
>
>
> If the galvanizing is compromised and you have a bit of soil moisture you
> have the makings of a battery with the steel or iron as one plate and the
> galvanizing as the other. This battery (actually single cell) is shorted
> (the zinc is in contact with the steel/iron) permitting current flow. It
> will eat itself.
>
> Copper clad ground rods and galvanized or bare steel both in the ground
> can
> comprise the plates of a single cell (will register nicely on a voltmeter)
> but not much happens until there is current flow such as when the two
> plates
> are shorted together by running a wire from the ground rod to the guy
> anchor, tower, or anything electrically conductive connecting to the
> anchor.
>
> Patrick AF5CK
>
>
> -----Original Message-----
> From: K0DAN
> Sent: Thursday, June 20, 2013 12:43 PM
> To: towertalk@contesting.com ; Hans Hammarquist
> Subject: Re: [TowerTalk] Fwd: Screw Anchor Experience
>
> Hans...
>
> In my experience this is not true. I have some photos of my failed
> galvanized screw anchor which I can send you. The failure was a good 3+
> feet
> below the ground surface, however I expect the metal rod was probably
> compromised along its entire length.
>
> The property I am on was once a working farm. I occasionally find gears
> and
> other metal parts from farm implements I believe to date from the
> 1920's-1930's. This iron or steel parts are very solid and heavily rusted,
> and the rust protects it from deeper corrosion (think: ocean
> liner)...galvanized anchors, on the other hand, are not the same compound.
> (Metallurgists please chime in). I suspect that the steel underneath the
> galvanizing may be a very soft/cheap material (keep the costs down no
> matter
> what), and once the galvanizing is compromised it does not take long (15
> years in my case) for the actual metal to be totally compromised.
>
> What you describe for poles, fence posts, etc., is true, but I suspect we
> are comparing apples and oranges. And again, we should not assume that all
> soils are created the same. What I have here in west central Missouri is
> probably much different than soils and ground water in other parts of the
> country.
>
> As always YMMV.
>
> 73
>
> Dan
> K0DAN
>
> -----Original Message-----
> From: Hans Hammarquist
> Sent: June 20, 2013 11:38
> To: towertalk@contesting.com
> Subject: [TowerTalk] Fwd: Screw Anchor Experience
>
> What I have seen, it is only the portion closest to the surface that
> corrodes. I have found iron pieces buried for hundred of years with only
> slight corrosion. Scrap iron, stored laying on the ground, has almost
> disappeared in no time. I believe it is a combination of water, "dirt",
> and
> air that is causing this.
>
>
> When installing fence with steel poles, a concrete "plate" is made around
> the pole just at the surface. It is sloped on the top to allow water
> run-off. If you don't do that the pole will corrode at the surface and
> eventually break there.
>
>
> The rebar in concrete is "protected" by the concrete but will corrode if
> too
> close to the surface. In the same way the fence pole is "protected" by the
> concrete plate.
>
>
> Maybe some concrete poured around anchor can extend the life-expectancy of
> the anchor.
>
>
> Next: What method or how would you inspect an anchor for corrosion
> damages?
> Just digging around it?
>
>
> Hans - N2JFS
>
>
>
> -----Original Message-----
> From: Mark Robinson <markrob@mindspring.com>
> To: Jim Thomson <jim.thom@telus.net>; towertalk <towertalk@contesting.com>
> Sent: Thu, Jun 20, 2013 11:36 am
> Subject: Re: [TowerTalk] Screw Anchor Experience
>
>
> Jim wrote
>
>
>> ## why mess with screw in anchors ? Only power companybs + telcobs use
>> em. Even then
>> they use eggs in the EHS guys. A 40b tall utlility pole is already 6
>> feet into the ground. No
>> anodes used.
>>
>> ## The rohn type rod anchors are in contact with the soil, where it is
>> trenched, so that portion
>> of the rod needs to be coated with roofing tar pitch. Those GAC series
>> anchor rods involve
>> excavating a huge hole, that is then trenched. The concrete slab needs
>> to
>> be poured, then the
>> entire mess is bakfilled with dirt.
>>
>
> I reply...
>
> They weren't screw anchors. They were the Rohn supplied anchors set in
> concrete per the Rohn specifcations (as you describee) BUT they are still
> vulnerable to corrosion. I have read dubious accounts of using tar on the
> buried metal parts - the tar can fail and then the corrosion will be
> concentrated in the failed areas
>
> My opinion/guess is that the sacrificial anodes are a better way to go but
> only time will prove me right or wrong.
>
>
>
> Mark N1UK
>
>
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