The standard EN54-4 contains specific requirements for all power supply devices, external or included in the control equipment of the evacuation and sound system (ECSAV).
The power supplied in the ECSAV comes from at least two power sources : principal power source, and a standby power source.
According to the standard EN54-4 at least a standby power source has to come from a rechargeable battery. The PSU device has to consist of a of load batteries device capable of maintaining them completely loaded permanently. (We also tender battery supply, consult us).