Over the past 50 years, surgery, physiologic monitoring, and the delivery of anesthesia has undergone a high technology revolution. The finger on the pulse, manual blood pressures, and precordial stethoscopes have given way to advances in electrocardiography, automated blood pressure, pulse oximetry, end-tidal capnography, and transesophageal echocardiography, just to name a few of the major advances. As automation has progressed, anesthetic practice and surgery have become extremely dependent upon a reliable power supply for clinical operations. The Joint Commission (TJC) standards require routine testing of the hospital backup power supply (EC.02.05.07.04); 12 times a year, at intervals of not less than 20 days and not more than 40 days, the hospital tests each emergency generator for at least 30 continuous minutes. The completion dates of the tests are documented in the generator and automatic transfer switch (ATS) testing logs by the technicians performing the tests. Additional specifics are addressed in TJC standards on load testing and performance.