The network structure and therein the flexibility for reconfiguration together with the grounding (earthing) methods that impact the determination of fault location. This chapter examines these two areas, as they affect selection of distribution automation systems. The chapter looks at the aspects of network design where there is an interaction with automation and provides a basic knowledge of this interaction. One basic problem for the distribution network designer is the way that the neutral is earthed because it affects a number of technical and economic solutions. The most important items are the relay protection, operation principles, equipment earthing and power system component selection. The design of the medium-voltage (MV) network, by which the distribution substations are connected to the network source substation, plays a significant part in the cost of the overall network. It also plays a significant part in the way that the network will perform.