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ETL 1110-9-10(FR)
5 Jan 91
2-9.
Horizontal Anodes. (Underground Applications)
There are times when it is advantageous to install anode
horizontally as shown in figure 2-24. For further information,
see paragraphs 10.91 through 10.93 of TM 5-811-7 (reference
10). This configuration is particularly helpful when using
packaged ceramic anodes (figure 2-24) since earth backfill can
be solidly tamped around them. The anodes can be laid on the
bottom of a trench or excavation with compacted backfill. This
often achieves better compaction than when tamping in vertical
holes.
The design is undertaken in the same manner as
described in Section 2-2 and 2-3. The single anode-to-earth
resistance is calculated by using equation 2-11:
(eq 2-11)
Where:
RA
=
Anode-to-electrolyte resistance in ohms.
p
=
Electrolyte resistivity in ohm-cm.
L
=
Length of anode in ft.
d
=
Diameter of anode in ft.
h
=
Depth of anode in ft.
This equation is used to calculate the resistance
of a single anode-to-earth.
For multiple anode installations, equation 1-11 may be used to
approximate total resistance:
RA
p PF
RN '
%
N
CC
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