There is provided an electric wiring system in which a plurality of electric components, a plurality of command switches for actuating the electric components and a plurality of sensors, etc., are provided at various points of an automotive vehicle, transmitting and receiving units of time-shared pulse transmission type which are arranged at the various points of the vehicle are interconnected through a plurality of electric wires or lines, the electric components or loads are divided into a plurality of locals each thereof including a group of the loads, and the transmission and reception of information between the respective locals and a command section is effected by a time-shared pulse transmission method, whereby reducing the hazard of short-circuit fault.