The subject matter of the invention is an apparatus for testing a protective, measuring or metering device as a constituent part of a high or medium voltage installation, more specifically of a utility protective relay, of a generator protective device, of a current meter and so on in a high or medium voltage installation, a combined terminal and pole block (1) located in the input field of the high or medium voltage installation being connected in the protective field to the protective, measuring or metering device, said terminal and pole block (1) comprising several terminal and pole segments (2) disposed behind each other, each terminal and pole segment (2) comprising on its upper side a pole opening (5) for receiving the pole blade (7) of a plug (8), each terminal and pole segment (2) having a cable clamping apparatus (27; 31) on either side thereof, said cable clamping apparatus (27; 31) being accessible through an opening (22a) for the cable disposed in the side wall of the terminal and pole segment (2).