This International Standard applies to movable, stationary and fixed electronic uninterruptible power systems (UPS) that deliver single or three-phase fixed frequency a.c. output voltage not exceeding 1 000 V a.c. and that incorporate an energy storage system, generally connected through a d.c. link.

This standard is intended to specify performance and test requirements of a complete UPS and not of individual UPS functional units. The individual UPS functional units are dealt with in IEC publications referred to in the bibliography that apply so far as that they are not in contradiction with this standard.

The primary function of the UPS covered by this standard is to ensure continuity of an a.c. power source. The UPS may also serve to improve the quality of the power source by keeping it within specified characteristics. UPS have been developed over a wide range of power, from less than a hundred watts to several megawatts, to meet requirements for availability and quality of power to a variety of loads.