The effects of lightning strikes on earthing or protection systems designed to IEC 62305 can be modelled using an equivalent single frequency from 25kHz up to 1MHz which gives similar results to a time-domain approach. This article provides the frequency and current values to be used for modelling lightning.

This report shows the effects of a direct lightning strike to an air terminal installed on top of a building which is connected to a buried earthing system.

Low voltage earthing systems include TN-S, TN-C-S, TT, IT and DC. High voltage earthing includes solid, ungrounded, resistance, reactance and resonant.

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.

Earthing rods improve earthing systems when driven into low resistivity soil layers. Due to the proximity effect the rule of thumb is earth rods should be separated by at least their driven length. Rods may be encased in concrete to lower their resistance. Equations are provided for hand calculations and these have been validated with numerical software.

Soil electrical resistivity varies based on several factors. Use these tables to validate your soil measurements or devise a soil model without having measurements for preliminary earthing/grounding designs.

This article provides typical values for surface layer resistivity to be used for earthing and ground electrical calculations of touch and step voltages.

We compare the best and latest earthing and grounding system design software including SafeGrid, CDEGS, XGSLab, ETAP and more based on technical features and compares price.

Soil resistivity is one of the most critical factors affecting earthing and grounding system performance and safety. In cold climates, the top-soil layers may be frozen during the winter or spring seasons, and resistivity may increase to as high as 10,000 Ω.m in the frozen soil layers. This can give rise to significant touch voltage hazards during an earth fault.