This paper discusses the application of the following types of cables and methods of laying to the various parts of a three-wire d.c. network.Types of cables: Single-core, three-core, and triple-concentric.Methods of laying : Conduit, direct, and solid.It endeavours to show that, wherever it can be adopted, the most satisfactory network is that composed of single-core lead-covered cables, the feeders being drawn into conduits and the distributors and services laid direct.The paper also describes the “looped-neutral” service, the object of which is to facilitate the location of faults on the smaller sizes of triple-concentric vulcanized-bitumen distributors, and to improve the continuity of supply under fault conditions.