What is the role of potential monitoring in a CP system?

• A. Potential monitoring tends to increase system cost and has no functional benefit.
• B. Potential monitoring lowers the risk of measurement noise by calibrating sensors.
• C. Potential monitoring verifies that the protected structure remains within the target CP range and helps detect over- or under-protection and anode depletion.
• D. Potential monitoring is used to adjust coating thickness during operation.

Answer: (C)

Potential monitoring is about confirming that a protected structure stays within the specified protection range and providing early warning when the system isn’t delivering the needed current. By measuring the structure’s potential relative to a reference electrode, you get a direct read on whether the CP system is achieving the target protection level. If the potential stays within the desired window, corrosion protection is effective; if it drifts too positive, the structure may be under-protected, and if it drifts too negative, there’s a risk of over-protection and related issues like hydrogen evolution. Monitoring also helps spot anode depletion: as anodes wear out, the available current drops and the structure potential can shift, signaling that adjustments or replacements are needed. This continuous feedback is essential for keeping the CP system reliable and for diagnosing problems quickly.

The other options aren’t the primary role of potential monitoring. It isn’t mainly about reducing measurement noise through sensor calibration, and it isn’t used to adjust coating thickness during operation.