A surge arrester for the power supply of low-voltage systems, having a housing, two electrodes which are situated axially opposite one another, an arc combustion chamber formed in the interior of the housing, and a trigger aid. A spark gap is formed between the two electrodes so that an arc is produced when the spark gap between the two electrodes is triggered, the axial distance between end faces of the two electrodes being so large that the arc voltage is greater than the expected line voltage. Conversion of energy within the surge arrester is reduced by the arc combustion chamber having an inner region and at least one expansion region into which the arc can propagate after triggering. The inner region is arranged between the two electrodes and is delimited axially by the end faces of the electrodes and is delimited longitudinally by the at least one expansion region.