This document applies to voltage class B electric propulsion systems and connected auxiliary electric systems of electrically propelled road vehicles. Additionally, it applies to electric circuits and components in these systems. This document provides specifications of voltage sub-classes related to DC electric circuits. It also provides specifications of characteristics which are relevant for design and operation of systems and components for the voltage sub-classes. This document does not cover electrical safety (see ISO 17409 and the ISO 6469 series).