JANUARY 31 2003
Advantages and Disadvantages of Impressed Current Anode Systems
Economically feasible when installed on existing structures.
Large voltage available (potential difference limited only by the size of
Large current available, even in very high resistivity electrolytes.
Can provide sufficient current to protect very large, poorly coated, or
Economically feasible to replace anode system when required.
Significant operation and maintenance requirements.
Relatively large chance of premature failure or breakdown.
Possibility of stray current causing interference damage to other metallic
Impressed Current Test Stations. Test Stations for structures with
impressed current cathodic protection systems normally are merely contact points for
the positive connection of a voltmeter to allow for potential testing. Normally, there are
two wires to the test station to permit test lead verification and redundancy. Also,
impressed current systems require the same test stations as galvanically protected
bonds. Any location where the structure is assessable could be considered a test
station. These locations could be where a pipeline goes through a valve pit, low level
drain pit, high level drain pit, exposed crossing a ditch, goes aboveground for a valve or
meter, or enters a building or any other location where it is exposed.
Test stations should be installed wherever the structure is inaccessible to
allow the ability to test the cathodic protection system(s). Examples of such areas
include paved areas and structures under concrete slabs. In these cases, the test
stations provide a contact point for the reference electrode as well as test leads to the