Underground Corrosion and Electrical Grounding

Underground corrosion associated with electrical grounding has caused numerous problems in operating electric systems. Much of the difficulty is due to dissimilar metal effects between buried copper and steel connected together via the grounding network. Unfortunately, these effects are widely ignored in electrical design and the requirements of electrical protection and corrosion mitigation are often seen as opposing each other. Experience has shown that both sets of requirements can be met. On electric distribution lines, the most helpful measures against corrosion include the use of galvanized steel rather than copper for grounding electrodes. Sacrificial anodes are helpful for adding additional corrosion protection where needed. Underground copper wire should be tinned or otherwise coated to avoid or minimize dissimilar metal effects. Research is in progress for determining what coatings would be best for this purpose.