In my thesis I describe a design of a system supporting an uninterruptible power supply of a bank center. I review those characteristics of the building, which may be relevant to the design point of view, including the design of the normal power supply. Then categorize the possible consumers on that basis to what extent are they able to tolerate network anomalies due to their operation or function. To make the best solution I review the possible embodiments, examine their applicability in the bank center. After taking into account other factors - such as investment and operating costs, maintenance, availability – I select the components and present the overall system architecture. After calculations I determine the necessary capacity and performance. I also describe the electrical connections, and the right choice of the switching and protection automation which guarantee reliable operation, bearing in mind the recommendations of the relevant standards. Finally, using the standard procedure I determine the reliability of the availability in the developed system.