This International Standard specifies dimensional and functional requirements for the compatible mounting of switchgear, controlgear and accessories on some types of rails. The object of this standard is to specify those dimensions which are critical for the correct design of mounting rails and equipment. The following sections are covered by this standard: "Top hat" section; "C" section; "G" section. NOTE 1 Mounting compatibility does not imply functional interchangeability. Annexes deal with specific steel mounting rails satisfying the requirements of this standard, and give additional dimensional data and loading requirements applicable to such rails. NOTE 2 T he detailed design and material of specific steel rails is given in the annexes. NOTE 3 Other shapes of rails complying to this standard not listed in Annex A can be used. Mounting rails used as protective conductor are covered by IEC 60947-7-2. This international standard has the status of a horizontal standard in accordance with IEC Guide 108:2006.