The mission of this project was to provide the mobile telecom switch office (MTSO) with upgraded commercial and emergency power systems capacity and reliability to support the increasing power demands of the digital computerized telecomm equipment. Among other improvements, this project included alterations to the existing commercial and emergency power switchgear to accommodate the increased power load and the installation of a new 1.5 mw emergency power generator system. The upgraded emergency power systems included complete new fuel, building automation systems, and alarm systems. The installation of the new generator required careful rigging and placement inside the facility through an existing exhaust air louver opening. Since all work was performed in a live 24/7 MTSO, daily construction activities were carefully coordinated with the building operations personnel. Potential service affecting activities were conducted by strict adherence to the Method of Procedure protocol. In the event that commercial utility power was lost during critical switchgear modifications, two portable 1.5 mw temporary generators were connected to the facility power systems to provide back-up emergency power while the existing power systems alterations were being performed. The project was safely completed on time, on budget, and fully commissioned with no loss of service to the live MTSO.