Stray current corrosion is caused by external electrical currents. Which mitigation measures are commonly used?

• A. Caused by external electrical currents; mitigated by isolation, proper CP adjustment, and coatings to prevent current flow.
• B. Caused by humidity; mitigated by painting.
• C. Caused by mechanical wear; mitigated by lubrication.
• D. Caused by magnetic interference; mitigated by magnetic shielding.

Answer: (A)

Stray current corrosion is driven by external electrical currents entering metal structures, creating localized anodic areas that speed up corrosion. The most effective mitigation combines interrupting the current path and reducing the metal’s exposure to those currents: isolating the structure from external conductors or grounding paths stops stray current from entering it; properly adjusting the cathodic protection system maintains the metal at a protective potential so any incoming current doesn’t drive corrosion; and applying coatings provides a physical barrier that blocks current flow into the metal and lowers current density on the surface. Other approaches don’t address the electrical path—humidity and painting alone don’t stop stray currents, lubrication tackles wear rather than electrical corrosion, and magnetic shielding isn’t the right tool for preventing stray current-induced attack.