On the afternoon of the biggest power failure in the nation’s history, Tim Markijohn was driving on Interstate 90 when Hamot Medical Center’s power management system sent an alpha-numeric page to his beeper. That day, Aug. 14, 2003, a cascading failure of the power grid serving the northeastern United States and southeastern Canada left many towns and cities in the dark, and caused voltage in many facilities to swing wildly. In addition to paging Markijohn and more than 40 Hamot Medical Center maintenance technicians, the system took first steps to maintain power, in keeping with requirements of the National Fire Protection Association (NFPA) and the federal Joint Commission on Accreditation of Healthcare Organizations (JCAHO). Having sensed multiple voltage sags, transfer switches in the power management system switched loads to back-up power generators. The three diesel-powered generators began cycling on and off as the sags continued intermittently, putting substantial strain on the 1,000-horsepower units.While the power management system was doing its job, so were Markijohn and Hamot’s Hospital Emergency Incident Command Structure (HEICS). According to a well-practiced plan at the Erie, PA-based facility, after the second power “bump,” the HEICS team assembled in its predetermined command center and began assessing damages. Based on power fluctuation reports from the HEICS team, Markijohn determined that utility power was too unstable, decided to shift power from the utility feed to the generators, and dispatched maintenance technicians to the facility’s 32 transfer switches. They manually activated the switches, locking in the emergency power supply.“The HEICS team contacted a short list of predetermined electrical contractors, who were held in reserve to provide emergency maintenance,” notes Tim McQuone, Hamot’s director of emergency and trauma services and the hospital’s designated incident commander. “At that point, we were not aware of the situation outside, so we responded based on a response plan that we practice every month.”By 6:00 p.m., Hamot Medical Center had transferred completely to generator power, which provided an emergency load equivalent to three-quarters of the normal facility power supply. That load covered all life-sustaining critical equipment and emergency lighting.Throughout the evening, the city of Erie maintained power. When the utility company, First Energy, notified McQuone that it believed power was stable enough to transfer back to the utility feed, Markijohn opted to continue running the generators for another several hours to assure utility service reliability. By approximately 8:00 a.m. on Aug. 15, Hamot Medical Center transferred back to its utility feed with no damage to patient care and no long-term damage to equipment.Gary Morse is Square D PowerLogic business specialist in Erie PA.