Device protection against overvoltage

The protective device against overvoltages (SPD) comprises a spark gap (SG) and, in series with the spark gap (SG), a resistance element (R) varies with temperature, with positive temperature coefficient. The spark gap (SG) has a defined holding current. The resistance element (R) is dimensioned such that when a switching temperature is reached, the current is limited so as to be less than the holding current of the spark gap and that the holding current is switched off. The resistance element is dimensioned so that, in case of transient event, the switching temperature is reached.