规定了在标称28 V直流和115/200 V三相400 Hz交流系统中使用的这些开关的单孔和三孔安装值。与仅在操纵杆入口密封的2级开关相比，它们是环保密封的，适用于更高的海拔和温度条件。它们不具备ISO 1466中规定的1级和2级开关的积极作用特征。

Specifies the values for single- and triple-hole mounting of these switches for use in nominal 28 V d. c. and 115/200 V three-phase, 400 Hz a. c. systems. They are environmentally sealed and suitable for higher altitude and temperature conditions than are Class 2 switches which are sealed only at the lever entry. They do not have the positive action features of the Class 1 and Class 2 switches specified in ISO 1466.