System for overvoltage protection

System according to one of the proceeding claims, in which the switch (3) may be switched off by means of an earth leakage circuit breaker.

System according to one of the proceeding claims, in which the surge protective device of the second type (9, 11, 12) is non blowing-off

System according to one of the proceeding claims, in which the elements of the power supply unit are positioned inside a closed cabinet.

System for surge protection of an object comprising a supply unit, which is connected to the secondary output of an external transformer,

• in which the secondary windings (1) of the external transformer are coupled in a star configuration, the star point of the transformer being connected to a downstream neutral conductor (7) and an earth electrode provided near to the transformer, characterised in that,
• in the supply unit at least one phase conductor (6) is connected to the neutral conductor (7) by means of a surge protective device of a first type (4), and the neutral conductor (7) is connected to an earth electrode (5) provided near to the supply unit by means of a surge protective device of a second type (9), and in which the surge protective device of the second type (9) has a rating of at least 40 kA, more preferably at least 50 kA and even more preferably at least 100 kA.