The emergency power supply, unlike standard UPS, has in addition the requirements compliant with EN 50171 and is defined Central Power Supply System (CPSS o CPS).

The characteristics peculiar to the emergency power supplies make them specifically suitable for applications in public places, offices, factories and environments that are subject to safety regulations. Some examples of their use are: centralized emergency lighting systems, alarm and safety systems, fire extinguishing systems, smoke extraction/ventilation systems, carbon monoxide detectors and high-risk facilities.


The main technical specifications that distinguish a CPS from a UPS are the following:

Batteries powered by a CPS must have a declared expected lifetime of 10 years and must guarantee performances and autonomy until the end of their useful lifetime.

In addition, a CPS must be equipped with a battery protection system against deep discharge, an event that may reduce its expected lifetime, and against accidental reverse polarity.

The super charger can charge totally out of power batteries up to 80% in approximately 12 hours. A battery charger requirement is the possibility to reduce the floating charge according to the environment temperature, in consideration of the fact that high floating voltage with high temperature could compromise batteries duration.


The inverter can power permanently 120% of the maximum load for the whole nominal duration and is protected against output short circuits.

Furthermore, the CPS includes three different operating modes:

ONLINE : in this mode, the load is always powered by the inverter. In case of power failure, the inverter picks power from the batteries instead than from the rectifier, without ever disconnecting the utilities.

ECO MODE: the load is normally powered by the bypass line. Only in case of input power failure, the load is transferred from the bypass to the inverter (maximum switched time set by regulations: 0,5 seconds).

SOLO EMERGENZA: when operating normally, the load is always off. In case of power failure, emergency lights are switched on.


The external wrapping structure of the emergency power supply must have a protection degree of at least IP20 and it must be in metal carpentry to comply with specific thermal stresses.
Regulations also require warnings through potential-free alarm contacts, referred to: normal operation, on battery running, pre-alarm end of autonomy condition, general alarm and protection from deep discharge.

ACPS, like UPS, need specialized maintenance and must be submitted to periodical checks by specifically certified field service technicians.

NMore specifically, legislation states that, in order to guarantee the correct functioning, all the functionality characteristics will have to be verified, as well as the battery autonomy and efficiency and the correct functioning of all the inner devices (rectifier, battery charger, inverter, static switch, PFC, etc.).