ABSTRACT Reliable electrical power is required for safety, security, financial, and many other business reasons. This article will discuss the levels of power continuity, and various methods for making sure that reliable power is available 24 hours a day, 7 days a week. The cost of power continuity is directly related to increased availability, and reliability. The cost of downtime can be measured by the loss of human life, product, equipment, revenue and inconvenience. Uptime cost must be weighed against the cost of providing additional equipment, which can include on-site generation, redundant services, and UPS systems. Equally important for obtaining power reliability are proper design, redundancy, and elimination of single points of failure; training, testing and maintenance.