A distribution line for installation vertically in a building consists of parallel insulated conductors 12 enclosed in rigid ducts 14, the ducts being spaced apart at intervals so as to leave flexible portions 18 which allow the line to be folded for transport and to allow thermal expansion and contraction. The ducts 14 is in halves and has removable portions 20 to allow connection of electrical wiring. Protective plates may be attached between the ducts 14 to protect the flexible portions when the line is installed, or wires may be attached between the ends of the ducts to prevent stress on the conductors during installation; one of such wires may serve as an electrical earth (Figs. 21 to 26). Waterproof caps may be fitted to the ends of the ducts. Spring catches (48, Figs. 30 & 31) secure the duct as it passes through holes within the building. <IMAGE>
