Abstract: Apparatus for reducing surge voltages comprising at least one voltage surge suppressor arranged in a holder which has an insulating housing and connecting terminals for connection of external electrical conductors to the apparatus. A metallic foot is so formed on the insulating housing that it, together with an associated pressure member, enables the apparatus to be mounted and rigidly clamped by way of a screw bolt in the manner of a terminal block or the like on a protective earth collector rail. The foot is electrically connected with one terminal of the surge suppressor. The other terminal of the surge suppressor is connected with at least one connecting terminal. On rigidly clamping the apparatus to the collector rail, which at the same time serves as a carrier rail, the required connection between the surge suppressor and the protective ground is automatically produced.