给出了标称28 V直流和115/200 V三相400 Hz交流系统中使用的两类单孔固定开关的要求。1级开关是密封的，适用于比2级开关更高的海拔和温度条件，2级开关仅在操纵杆入口密封。此外，还规定了尺寸、操作、结构、电压和电流额定值、环境、试验、型式试验、生产试验、质量试验、声明和标记的要求。

Gives the requirements for two classes of single-hole fixing switches for use in nominal 28 V d. c. and 115/200 V three-phase, 400 Hz a.c. systems. Class 1 switches are sealed and are suitable for higher altitude and temperature conditions than are Class 2 switches, which are sealed only at the lever entry. Furthermore, gives requirements for dimensions, operation, construction, voltage and current ratings, environment, tests, type tests, production tests, quality tests, declarations and marking.