During a tank test, the cathodic protection system should be kept on when?

• A. At all times
• B. Only during testing
• C. Not used
• D. Only during night

Answer: (A)

Cathodic protection provides corrosion protection by making the metal surface a cathode in the electrolyte. During a tank test, the inside of the tank is a conductive environment, so keeping the CP system energized maintains the protective potential across the test period. If protection is turned off, the steel is left unprotected, which can accelerate corrosion, potentially affect test readings, and obscure or degrade signs of leaks. Since CP is normally kept on to protect the structure during service, it should remain on continuously during testing as well. Therefore, the best practice is to keep it on at all times.