本SAE推荐规程定义了与民用飞机400周地面电源一起使用的各种保护装置的术语，并列出了其特性限值，旨在帮助航空公司实现400周保护系统的标准化。给出了民用飞机行业可接受的限制。

This SAE Recommended Practice which defines the terms and tabulates the limits of the characteristics for various protective devices used in conjunction with 400-cycle ground power for civil aircraft is intended to assist the airlines in standardizing on 400-cycle protective systems. The limits found to be acceptable in the civil aircraft industry are presented.