For purposes of protecting electrical installations against electromagnetic disturbances, especially overvoltages, for instance, as a consequence of lightning strikes, wiring lines laid for connecting individual electrical apparatus are surrounded by a shielding, which is formed by a braiding, consisting of electrically conducting material and which is in connection with connector elements arranged at its ends. The connector elements, as well as an additionally provided terminal, branching and attachment elements, comprise, respectively, a transitional part over which the braiding is pulled and on which it is fastened by means of a clamping element. In addition, further sheaths of a plastic braiding are provided between the electrical shielding and the electrical lines.