[TowerTalk] Ground Rods into Concrete Stubs

[K3GM]

Hey Mike,

What you're proposing to do has the makings of what is referred to as a Ufer
ground.  Named for its inventor, the principle of the Ufer ground is simple.
It is very effective and inexpensive to install during new construction. The
Ufer ground takes advantage of concrete's properties to good advantage.
Concrete absorbs moisture quickly and looses moisture very slowly. The
mineral properties of concrete  and
its inherent pH means concrete has a supply of ions to conduct current. The
soil around concrete becomes "doped" by the concrete enhancing its
effectivness.  The moisture present, (concrete gives up moisture very
slowly), in combination with the "doped" soil, make a good conductor for
electrical energy or lightning currents.  Ufer techniques are used in
building footers, concrete floors, radio and television towers, tower guy
wire anchors, light poles, etc. Copper wire does not function well as a
"Ufer" ground due to the pH factor of concrete (+7pH is common). The use of
steel reinforcement as a "Ufer" ground works well and concrete does not chip
or flake as has been found with copper. The use of copper wire tied to the
reinforcement rods outside the concrete shows none of these problems.   In
your case, I would add additional rebar to your installation making sure the
rebar  "cage" is attached to the base stub by welds.  The notion that your
concrete pad will explode is unfounded according to Polyphaser's "Grounds
for Lightning Protection" publication.

7 3.......Tom K3GM



>
> I'm in the process of getting a tower put in, a 48' Rohn HDBX.
>
> Is there any reason that I can't take and attach 3 ground rods to the
BOTTOM
> of the base stubs (that are buried in the concrete)?  That would put them
> another 4-5 feet down.
>
> I am planning on also putting in some more ground rods (8 footers I
imagine)
> in the immediate vicinity also.
>
> Mike
>
>



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