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ETL 1110-9-10(FR)
5 Jan 91
I
=
2358 mA or approximately 2.4 amp
which agrees well with the current requirement test
data provided in item 12 of paragraph 2-2a.
3)
Select an anode and calculate the number of anodes
required (N) to meet the design life requirements. Two
sizes are selected for trial calculations using
equation 1-2:
N=
I
IA
Where:
I
=
2.8 amp (Current requirement from item
12 of paragraph 2-2a)
IA
=
Current rating per anode, varies de-
pending on anode size from table 3-3.
Several different size anodes could be chosen.
Experience has shown that for this type of groundbed,
60-in. long anode packages are desirable.
For a 3-in. by 60-in. packaged canisters with a 1/8-in.
by 48-in. ceramic anode rod, IA = 1.2 amp/anode (from
table 3-3 for 15-year design life).
= 2.33; use 3 anodes.
N=
2.8
1.2
For a 3-in. by 60-in. packaged canister with a 1/4-in.
by 48-in. ceramic anode rod, IA = 2.4 amp/anode (from
table 3-3 for a 15-year design life).
N=
2.8
= 1.17; use 2 anodes.
2.4
4)
from equation 1-6:
RA =
p K
L
Where:
p =
2000 ohm-cm (Soil resistivity in area
where groundbed is desired from item 1
of paragraph 2-2a)
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