The article describes a method for calculating large earthing systems, which generally consist of elements such as various earthing electrodes (mesh and rod earthing electrodes, metal pipes, etc.) and passive overhead and insulated electrical circuits (transmission line earthing cables, cable sheaths, etc.). The mutual conductive and inductive coupling between the elements of the earthing system that occurs under conditions of grounding connections is also taken into account. The earthing electrode is presented as an equivalent model of the electrical network whose elements, by assumption, are not equipotential. The proposed calculation method allows for careful computer analysis of various problems in the field of earthing, such as: designing an optimal earthing system, analyzing the mutual influence of multiple earthing electrodes, more precisely determining the danger of the potential being raised, etc.