Abstract: An electrical apparatus having a modular structure is characterized by a connection module that can be mounted on a carrier rail that is provided with connection levels including double or multiple connections and a serial alignment of disk-shaped base terminal carriers. Several power supply elements are provided on the terminal carriers, the elements being connected to the connection levels via bus bars of the disk-shaped base terminal carriers. The bus bars extend only on one of the sides of the base terminal carrier to the pertinent multiple connections. With the use of base terminal carriers, both a block structure and a disk structure as well as a combination of the two can be constructed.