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 mono