What is the role of a reference electrode in CP potential surveys?

• A. To supply current
• B. To seal the environment
• C. To filter impurities
• D. To measure the potential of the structure relative to a standard reference.

Answer: (D)

A reference electrode provides a stable, known potential against which the structure’s potential is measured during CP surveys. It acts as a fixed benchmark in the electrolyte, and because it is designed to draw negligible current, it does not disturb the cathodic protection current flowing to the metal. By using a high-impedance voltmeter between the structure and the reference electrode, you obtain the metal’s potential relative to this stable reference. This enables you to assess whether the structure is sufficiently polarized to protect against corrosion and to compare the measured potential to standard CP criteria. It’s not intended to supply current, seal the environment, or filter impurities; its role is solely to provide a consistent reference potential for accurate measurements.