In a commercial installation copper plated steel rods are used around the
base of the tower, around the building and along the security fence.
Galvanized rods are used ath the guy point grounds. The object is to get
the ground resistance as low as possible around the tower and equipment.
The galvanized rods are used at the guypoints to increase the ground
resistance there and help prevent the fusing of the guy wires if the tower
were to take a direct hit.
The Motorola R-56 manual for site selection states that compression
fittings should not be used external to the building. If these must ne used
they must be inspected periodically to ensure that the wire cold flow has
nor reduced the contact resistance.
All references that I have seen suggest that external ground wires be cad
welded to the tower and ground rods.
Solid copper rods would be too soft to drive and would be expensive. Brass
rods would be expensive and not provide significantly better ground contact
than the copper plated steel rods.
The object is to get all of the eguipment and the connecting wires to the
same potential during a lightning event. If this object is not met
differences od potential exist and current flows. If the differences of
potential are great enough, electrical damage occurs and the magic smoke is
released.
73
Glenn
WB4UIV
At 04:40 PM 7/31/02 -0400, N2TK wrote:
>Does ir make much difference if the ground rods are solid copper, copper
>plated steel, galvanized steel, or brass rods?
>
>Also, is brass okay to use for a ground clamp to a Rohn tower or does brass
>also react with the galvanizing?
>
>Tnx
>Tony
>N2TK
>
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Glenn Little glittle@awod.com QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@amsat.org AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) ARRL TAPR
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