本推荐规程涵盖了工业和商业电力系统主电路和分支电路中使用的导体的保护，以防止短路和过载造成的损坏，以及机械危害、不利环境条件和不当处理造成的物理损坏。

This recommended practice covers the protection of conductors used in main and branch power circuits in industrial and commercial power systems against damage from short circuits and overloads as well as against physical damage from mechanical hazards, adverse environmental conditions, and improper handling.