Abstract: A power switching apparatus is disclosed which has an electrical conductor to which high voltage can be applied. A series of circuits formed by a switching point and a current-limiting element which contains PTC thermistors and varistors is arranged in the cable run of the electrical conductor. An apparatus for operating the switching point interacts with the current-limiting element. The current-limiting element has n (where n is a natural number greater than 1) series-connected parallel circuits each having at least one PTC thermistor and at least one varistor connected in parallel with it. A current sensor arranged in the cable run of the electrical conductor or those connections of one of the PTC thermistors and of the varistor connected in parallel with it which are interconnected at two junction points in one of the parallel circuits are operatively connected to the input of the operating apparatus.

Abstract: The current-limiting resistor has two connection electrodes (1, 2) which are arranged parallel to one another as well as a resistance body (3) which has PTC behavior and with which large-area contact is made by the connection electrodes (1, 2). A varistor (40) is in electrically conductive contact with the resistance body (3). The resistance body (3) contains two contact areas (50, 51) as well as a response point (60) which is connected in parallel with the varistor (40) via the two contact areas (50, 51) and implements a PTC transition above a threshold value of a current flowing through the resistor.Since the resistance body effects the electrical contact with the varistor (40) in the case of this resistor, no metal connection electrodes are required for the varistor. At the same time, due to the outward displacement of the response point (60) away from the varistor (40), the operational reliability of the resistor is considerably improved.