In normal condition, almost all office buildings are designed to use AC supply for powering the office equipment like computers, laptops, fans, lights, fax, printers etc. But most of the equipment consumes the power first by converting the AC to DC internally or externally. Nowadays, due to the development of renewable energy or AC/DC converter, there is a possibility of getting DC power and supply to the equipment directly. So office buildings can be designed using DC networks to use DC office equipment. This thesis focuses on the feasibility study of DC supply for office equipment like laptop, monitor, desktop computer, LED lamp, WiFi, Ethernet modem, coffee maker and printers. In the study, the DC supply system was modeled with the DC loads, and a comparative analysis was done for AC and DC supply in terms of voltage drop, power loss, energy saving, power quality, and efficiency in the steady state operation of the system. The major re-engineering aspect of the DC devices was identified and the cost benefit of manufacturing of the DC device was compared with the AC devices. In this study 70.96% of annual energy loss could be saved using DC system.