Spark-gap arrangement encapsulated in a pressure-proof housing, for diverting harmful disturbances due to overvoltage, comprising at least two electrodes disposed substantially opposite one another in a housing that is conductive or provided with a conductive coating, between which a discharge space is formed and which are insulated from the housing, characterized in that directly by way of the conductive housing a trigger voltage can be applied to form a subsidiary spark gap in the discharge space, so that by way of the subsidiary spark gap the main spark gap between the main electrodes can be ignited.