Corrosion issues for copper earthing (grounding) networks are:
- corrosion of the copper material in soil including effects of inhomogeneities.
- corrosion of earth electrodes from lightning strikes, fault and equalizing currents, and stray currents.
- corrosion of copper wires induced by cathodically protected objects or by other sources, as well as deteriorated electromechanical connections.
- corrosion of welds.
The literature review primarily covers corrosion of copper even if corrosion in soil of other materials used for conductors in soil is briefly covered. According to results from previous investigations and results reported in the literature, uniform copper corrosion in soil and corrosion induced by lightning strikes is estimated to be of minor importance for grounding systems for Swedish nuclear power plants.
Soil conditions resulting in aeration cells from poor ground preparation or earth electrodes pressed through the sand fill into e.g. clay soil may however result in local corrosion that may possibly be extensive. For both uniform and localized corrosion, long term data is however lacking.
