During an earth fault on a substation earth grid, the flow of current to the earth will produce voltage gradients. An earth grid that is properly designed will safely dissipate current into the ground.

Should a metal fence be bonded to the substation earth grid? The metal fences around substations keep people out but they pose earthing safety challenges. These metallic fences, which are easily accessible to the public and personnel, must be adequately earthed and touch voltages on them during an electrical fault must not exceed safe limits.

This article shows the effects of soil resistivity and thickness of layers on grid resistance for earthing systems in multilayer soils. Increasing the resistivity of soil layers tends to increase the grid resistance, no matter which soil layer that is. Increasing the thickness of any soil layer with high resistivity also increases grid resistance and if the soil layer thickness is increased for a low resistivity layer then the grid resistance will decrease. Software modelling is performed and the results are compared and shown to match well with those from CDEGS software.

Copper is often preferred for its superior electrical properties, while aluminum and galvanized steel are chosen for cost-effectiveness. Copper-clad steel can offer a balance between cost and performance. This article demonstrates which option is best for different scenarios.