Corrosion is the leading cause of below-grade grounding system failure. Left undetected, corrosion of ground conductors, ground rods, and buried metallic structures can silently degrade a facility's safety system over years or decades — until a fault event reveals the failure in the most dangerous way possible. This technical paper from E&S Grounding Solutions addresses the science of electrochemical corrosion as it applies to grounding systems, and describes the engineering solutions available to prevent or mitigate it.

The paper covers the mechanisms of galvanic corrosion, stray current corrosion, and microbially induced corrosion (MIC) in the context of buried grounding conductors and metallic structures. It explains how soil resistivity, pH, moisture content, and the presence of dissimilar metals all contribute to corrosion rates, and how CDEGS software is used to model corrosion risk and predict system life expectancy.

Cathodic protection (CP) solutions discussed include sacrificial anode systems and impressed current cathodic protection (ICCP), with guidance on when each approach is appropriate. The paper also covers the integration of CP systems with existing grounding designs to avoid interference and ensure both systems perform as intended. This document is essential for facility engineers, asset managers, and corrosion engineers responsible for the long-term integrity of buried metallic infrastructure.