ETL 1110-9-10(FR)

5 Jan 91

5)

Determine the total circuit resistance (RT), from

equation 1-3:

RT = RN + RW + RC

Where:

RN =

Anode-to-water resistance

RW =

Wire resistance

RC =

Tank-to-water resistance.

a)

step 4 above. (RN = RA since RA is equal to one

continuous wire anode).

b)

Header cable/wire resistance (RW) is solved using

equation 1-15:

LW RMFT

RW '

1000 ft

Where:

LW = 115 ft (Effective wire length. The

positive wires from the rectifier

to each end of the anode circle

will be approximately 115 ft long)

RMFT =

0.51 ohm (Effective wire resistance

per 1000 lin ft. Since there are

positive wires from the rectifier

to each end of the anode circle,

each wire will carry about one half

of the current [12.5

amp].

The

wires selected are No. 10 AWG.

Because the two wires are in

parallel, the effective resistance

is

one half the single wire

resistance [1.02 ohms per 1000 lin

ft/2 = 0.51 ohm])

RW

=

115 ft x 0.51 ohm

1000 ft

RW

=

0.06 ohm

c)

Tank-to-water

resistance

(RC)

and

negative

circuit resistance.

The negative wire is connected to the tank

structure near the rectifier, so its resistance

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