IEC 61534-21-2014 延长插槽系统--第21部分：墙面及天花板安装用延长插槽系统的特殊要求 Powertrack systems - Part 21: Particular requirements for powertrack systems intended for wall and ceiling mounting

This clause of Part 1 is applicable with the following addition: 1.1 Add the following paragraph: This standard specifies the particular requirements and tests for PT systems intended for mounting on walls and/or ceiling. They may be installed flush or semi-flush, surface mounted, suspended or spaced away from the surface using fixing devices.