Abstract: In a metal-clad, compressed gas-insulated high-voltage switching installation, installation parts can be cut off by a circuitbreaker and connected to the grounded casing by means of a grounding switch, insulated measuring electrodes connectable to the testing terminal of a capacitive voltage divider and to a display device being provided in the casing adjacent to the grounding switch, for observation of the conductor voltage.To obtain a simple test setup in a three-phase clad installation, two pin-type measuring electrodes are arranged respectively centrally between pairs of the three conductors in such a way that their rounded end protrudes into the interior of the casing.