A UPS sits between an electrical device and normal incoming mains power supply. The computer draws its power from the UPS, and the UPS draws power from the power socket. Small UPS are generally located close to the equipment they are protecting i.e. in a server rack or in a computer room. Large UPS are often located in computer rooms protecting lots of equipment, but they can also be found in a building basement or in a electrical distribution room due to their size.
