DIN EN 50123-4-1999 轨道交通.固定设备.直流开关装置.第4部分:室外直流复合隔离开关,室外隔离开关,室外直流接地开关
Railway applications; fixed installations - D.C. switchgear - Part 4: Outdoor d.c. in-line switch-disconnectors, disconnectors and d.c. earthing switches; German version EN 50123-4:1999