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ETL 1110-9-10(FR)
5 Jan 91
EPR/HY50 cable has been chosen.
The cable
lengths have been calculated based on the
following distances, which are illustrated in the
deep groundbed examples shown in figures 2-12 and
2-13:
From grade to top of backfill column
100 ft
From top of backfill column to top anode
10 ft
From grade to bottom of backfill column
205 ft
From bottom anode to bottom of backfill
column
10 ft
From anode hole to rectifier 2 cables
at 10 ft
20 ft
From top of anode assembly to bottom of
anode assembly
85 ft
Total cable length from top anode feed
to rectifier 10 ft + 100 ft + 10 ft =
120 ft
Total cable length from bottom feed
to rectifier 10 ft + 205 ft - 10 ft =
205 ft
Calculate top
cable
(RWT)
from
equation 1-15:
LWT RMFT
RWT '
1000 ft
Where:
LWT
=
120
ft
(Cable
length
from
previous calculation)
RMFT
=
0.1183 ohm (Resistance per 1000
lin ft of EPR/HY5O [table 3-6])
RWT
=
120 ft x 0.1183 ohm = 0.014 ohm
1000 ft
Calculate bottom
cable
(RWB)
from
equation 1-15:
Where:
LWB
=
205
ft
(Cable
length
from
previous calculation)
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