Earthing connections are a critical component of power utility systems, directly impacting electrical safety, fault current dissipation, and the long-term reliability of infrastructure. Whether installed above ground or buried, these connections are exposed to various environmental stress that can lead to corrosion, mechanical degradation, and eventual failure. Soil chemistry, moisture content, atmospheric pollutants, UV exposure, and thermal cycling all contribute to the deterioration of grounding connectors over time.
Corrosion is among the most persistent threats, particularly in earthing applications where connections are in continuous contact with soil or exposed to harsh weather conditions. Galvanic corrosion between dissimilar metals, crevice corrosion in improperly sealed joints, and stray current corrosion from nearby systems can all compromise electrical continuity and increase earthing system impedance. These issues not only affect performance but also pose significant safety risks due to elevated touch and step voltages.
This paper focuses on corrosion related challenges and mitigation strategies for earthing connections, with particular emphasis on the selection and application of connection methods. Industry guidance from IEEE Std 837-2024 provides performance-based criteria for qualifying permanent earthing connections. The standard defines acceptable connection types based on their ability to maintain mechanical integrity, low electrical impedance, and corrosion resistance over the service life of the system.
Three primary types of earthing connections are examined: exothermic welds, compression connectors, and mechanical connectors. Exothermic welding is often considered the most reliable method for buried applications, as it creates a molecular bond that is highly resistant to corrosion and does not loosen over time. Compression connections, when installed with proper tooling and materials, offer a viable alternative, particularly where exothermic welding is impractical or restricted. These connectors must be carefully chosen to match conductor materials, and their long term performance depends on both proper installation and environmental sealing. Mechanical connectors, only used in above ground applications for their accessibility and ease of installation, must be carefully protected with insulating compounds or enclosures to prevent corrosion ingress.
The paper also addresses key design and installation considerations, including the avoidance of dissimilar metals, surface preparation, sealing of joints, and the use of protective coatings. Periodic inspection and testing, including earthing resistance measurements and visual assessment of accessible connections, are emphasized as essential elements of a preventive maintenance program.
By adhering to IEEE 837-compliant practices and selecting appropriate connection technologies based on application and environment, utilities can significantly enhance the durability and safety of grounding systems. This paper advocates for a holistic approach that integrates standards based connection design, corrosion mitigation, and lifecycle maintenance to ensure reliable grounding infrastructure under real world operating conditions.