The two parameters result from the lightning current wave shape, i.e. from its front and tail times. The induced touch voltages are connected with the current front time, and the step and touch voltages, as voltage drops, are mainly connected with the current tail. The relation between the shock voltage – time characteristics and the lightning current wave shape parameters is given in Figure 8.8. It enables the selection of the average dangerous value of shock voltages ร both for induced voltages and for voltage drops.