Rraum was a self-organized exhibition space in a private flat in Frankfurt. All electric appliances of the household were moved in the room, which originally was intended as the exhibition show room, but that room was kept locked during my exhibition for the visitors. All other rooms of the apartment were open. The lamps, cooker, etc. were still functioning and stayed connected with the power sources of their original position by using hundreds of meters of extension cables. Thereby the kitchen loost its function and the accessible areas of the apartment remained in darkness. The starting point of the concept of the exhibition “The Black Cat” was the fact that in this household an equivalent amount of electricity was consumed as mysolarpowerplant was producing. The title refers to a novel of same denominator by Edgar Allan Poe and to the thought experiment “The Schrödinger Cat”, which was set up by the physicist Erwin Schrödinger to demonstrate a quantum mechanics paradox. In both cases the cat is hidden, but through its absence the cat serves as a hint to another covert phenomenon. The installation shows structural and phenomenological analogies to both references.