AbstractIt is known by experience that a single‐layer star wiring network is suited for the design of premises distribution network with a small number of terminals. On the other hand, it is anticipated that the star wiring network with more than one layer will be better when there are a large number of terminals. In the design of the star wiring network with more than one layer, there are a number of parameters to be determined, e.g. the number of nodes, the placement of nodes, and the reduction of cables. However, no method has been presented by which the optimal distribution network configuration can be determined. This paper aims at the determination of the optimal configuration for the premises distribution network with two‐layer star structure. A model is presented for the modified two‐layer star wiring network, including anew the tandem connection. The cost function is derived, and the network configuration is determined to minimize the cost function. As a result, parameters which are important in the design can be determined for the practical rectangular area, where the important design parameters such as the number of nodes, the placement of nodes and the necessity for reducing the cable, are determined from the given area size and the number of term