More than One Anode Bed

UFC 3-570-06

JANUARY 31 2003

7-10.10 More than One Anode Bed. If a current requirement test includes more

than one anode bed location; all current sources should be interrupted simultaneously

to measure the potential shift of the structure. The total current requirement is found by

adding the current from all power sources together. Always consider proper current

distribution and estimate the required current requirement for each individual system.

7-10.11 Completion of Testing. Upon completion of testing, turn all power sources

off, disconnect all cables, and remove temporary anodes. For ease of removal of

ground rods or small diameter pipes and conduit, use three flat metal bars as shown in

Figure 7-25.

Figure 7-25. Removing Temporary Anodes (Ground Rods)

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7-11

ELECTROLYTE RESISTIVITY MEASUREMENT. Resistivity is the property of

a material that determines the electrical resistance between two points within the material.

The most common units of resistivity are ohm-centimeters and ohm/cubic centimeters,

which are equivalent. Many factors in the operation of cathodic protection systems are

dependent upon the resistivity of the electrolyte. The corrosivity of the environment is

generally higher when the resistivity is low. The output of both sacrificial anodes and

impressed current anodes is also dependent upon the resistivity of the environment. The

resistivity of fresh water and seawater normally does not change sufficiently to affect the

operation of cathodic protection systems. However, the resistivity of soil environments

depends upon the amount of moisture present and is subject to wide variations. These

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