Multiple Levels and Classifications of Emergency Electrical Power Systems

Today, designers are faced with the challenge of ensuring that all important facility functions are protected from power failures both externally and internally by providing one or more backup supply to the primary source (typically utility service). Each application has its own unique requirements of the Emergency Electrical Power Systems (EEPS) for performance, reliability, and speed to assume the load, and the length of time it must be able to provide emergency power. Lack of industry-wide definitions and standards are severely limiting the availability of equipment and services from which the users can make the best choice for his particular needs. To solve these problems, organizations such as IEEE, EMA, UL and NFPA are now, through representatives of users, the insurance industries, consulting engineers, inspectors, and manufacturers, engaged in an effort to develop definitions and guidelines. Some of the basic problems are explored, the rationale behind the present industry efforts to find a solution is given, and an approach using multiple levels and classifications of Emergency Electrical Power System is suggested.