What is the purpose of measuring CP potentials against a reference electrode?

• A. To monitor ambient temperature.
• B. To determine current flow only.
• C. To determine if protection is adequate by comparing potentials to standards.
• D. To estimate mechanical strength.

Answer: (C)

Measuring CP potentials against a reference electrode is about checking whether the protective current is doing enough to keep the metal from corroding. The reference electrode provides a stable, known potential, so you can see the actual surface potential of the protected structure relative to a standard.

By comparing that measured potential to established protection criteria in industry standards, you can tell if the cathodic protection system is delivering adequate protection. If the potential sits within the recommended range, corrosion is effectively suppressed; if it’s not, you know you may need more CP current, a coating inspection, or other adjustments.

The other options don’t fit because this measurement isn’t about monitoring ambient temperature, directly determining current flow, or estimating mechanical strength.