Device for monitoring varistors integrated in a circuit

In a device for monitoring at least one varistor integrated into a circuit, in a housing at least one varistor and at least one element, especially of Palusol, whose volume increases upon unallowed heating of the varistor, are arranged. Furthermore, a circuit breaker connected into the circuit of the varistor or the main circuit is assigned to the element, and the volume increase corresponds to the switching path for opening the circuit breaker. In order to simplify the installation and to guarantee the operation, it is proposed that the varistor and the element whose volume is increasing when heated be assembled into one block (1) by means of a tight and heat-conducting sealing compound completely enclosing the element and be replaceably inserted into the housing (3) exhibiting the circuit breaker (13).