Abstract This article describes in detail principles of manufacturing of DC on-board harness for spacecraft based on a new 3D design technology. This technology puts together all activities of on-board harness production, starting from electrical design and up to the final product readiness. Based on the analysis performed we proposed: necessary software, methods of wires and connector contacts connection, applicable wires and connectors available in Russian and European markets, shielding and insulating materials, test methods. The article discusses benefits of lightweight supply buses technology implementation (as compared to bundle of wires), which are: mass reduction, electrical performances stability improvement, lesser capacity between supply lines, better interference immunity, better thermal performances.