The protective switching system has a separate information path (8) between branch switches (1) and their associated group switches (2) for the switch-off signal. The information path is a single electrical line outside the bus (3) and used in conjunction with earth. The single line is held at a given voltage w.r.t. earth. The switch-off signal is earth or a given potential. Alternatively the path may be a double line carrying two different voltages or it may be a given electrical condition (e.g. voltage level) on the information bus (3).
