This Standard specifies the general requirements for central power supply systems for an independent energy supply to essential safety equipment. This standard covers systems permanently connected to AC supply voltages not exceeding 1000 V and that use batteries as the alternative power source. The central power supplies are intended to energise emergency escape lighting in the case of failure of the normal supply, and maybe suitable for energising other essential safety equipment for example: - electrical circuits of automatic fire extinguishing installations; - paging systems and signalling safety installations; - smoke extraction equipment; - carbon monoxide warning systems; - specific safety installations related to specific buildings e.g. high-risk areas. Schematic representations of typical central power supply equipment are depicted in clause 4. When a UPS system is used to feed these essential safety systems, it must comply with EN 50091-1 and its relevant parts, and the additional requirements of this standard. The power supply system for fire alarms covered by EN 54 are excluded.