The invention relates to a switchgear cabinet or rack comprising a mounting unit, the front of which has vertical mounting profiles that laterally delimit an installation space for installed user-side units, said profiles having fixing sections for attaching mounting sections of the installed units, and comprising components of a detection device for determining the presence of an installed unit in an installation position of the installation space. he components of the detection device have a vertical detector strip that is attached to a mounting profile and contains detector elements associated with the installed positions and arranged on or in said strip and code carriers that are provided on the installed units, the information from said carriers being transmitted for evaluation via the detector elements to a monitoring and control unit, either wirelessly or by wire. Clearly-represented user information is achieved for the switchgear cabinet using light elements mounted on or in the detector strip, said elements being associated with the installation positions and achieved by the fact that the light elements can be controlled in accordance with the information in the code carriers.