In accordance with the present disclosure, a system and method for providing scalable and modular power infrastructure outside of usable rack space is described. The system may include a chassis configured to mount on the side of a rack. A power cable interface box (PCIB) may be disposed within the chassis, and the PCIB may receive alternating current (AC) power. The system may further include at least one power supply unit disposed within a slot of the chassis, with the at least one power supply unit receiving AC power from the PCIB and outputting direct current (DC) power to a busbar. The system may also include a battery back-up unit (BBU) element disposed within the chassis. The BBU element may charge from and discharge to the busbar.