This standard applies to Automatic Transfer Switching Equipment (ATSE) to be used - in emergency power systems with interruptionof the supply to the load during transfer, the rated voltage of which does not exceed1 000 V a.c. or 1 500 V d.c.. It covers ATSE provided with or without an enclosure.Devices necessary for the control (e.g. control switches, . . . ) and the protection (e.g. circuit-breakers, . . . ) of an ATSE shall comply with the requirements of the relevant IEC standards.ATSE used only for emergency lightingmay be subject to specific rules and/or legal requirements and are not, therefore, covered by this standard.