Which type of cathodic protection is preferred for poorly coated structures in high resistivity soils?

Impressed Current Cathodic Protection (ICCP) is preferred for poorly coated structures in high resistivity soils due to its ability to provide a more controlled and robust level of protection. In situations where coatings are inadequate, such as in the case of poorly coated structures, the risk of corrosion is significantly higher. High resistivity soils can complicate the effectiveness of cathodic protection systems, making it necessary to apply a stronger protective current.

Impressed Current CP systems utilize a direct current source that can supply a consistent and adjustable level of current to the anodes. This adaptability allows for greater effectiveness in diverse soil conditions, particularly where resistance is above normal levels. The ability to increase current output as needed makes impressed current systems effective at overcoming the challenges presented by high resistivity soils.

Additionally, impressed current systems can be designed to provide deeper penetration into the soil, which is essential to ensure that the current reaches all areas of the structure that need protection, especially when the coatings do not provide optimal shielding. This makes them the most suitable option for protecting poorly coated structures compared to other methods.