A device for monitoring a space by changing a sequence of a serial interconnection of closing contacts, in particular of cover switches in a security housing, having a series circuit variation apparatus, a security cover, at least two closing contacts, and a protective circuit, wherein said at least two closing contacts each have an open, electrically nonconductive state and a closed, electrically conductive state, wherein said security cover is set up to put each of said at least two closing contacts in a closed, electrically conductive state, wherein said protective circuit is set up to detect an opening of at least one of said at least two closing contacts, wherein said series circuit variation apparatus serially interconnects said at least two closing contacts, wherein the sequence of the serial interconnection of said at least two closing contacts can be changed by said series circuit variation apparatus.