IEEE 242-1986

This publication presents in a step-by-step, simplified, yet comprehensive, form the principles of system protection and the proper application and coordination of those components that may be required to protect industrial and commercial power systems against any abnormalities that could reasonably be expected to occur in the course of system operation. Coverage is limited to system protection and coordination as it pertains to system design treated in ANSI/IEEE Std 141-1986 [1]1 and ANSI/IEEE Std 241-1983 [3]. No attempt is made to cover utility systems or residential systems, though much of the material presented is applicable to these systems



Revision Standard - Superseded. The ANSI/IEEE Std 242-1986, the IEEE Buff Book, deals with the proper selection, application, and coordination of the components which constitute system protection for industrial plants and commercial buildings. System protection and coordination serve to minimize damage to a system and its components in order to limit the extent and duration of any service interruption occurring on any portion of the system. This recommended practice is for use at the system design stage as well as in modifying existing operations. It is arranged in a convenient step-by-step format. Complete information on protection and coordination principles designed to protect industrial and commercial power systems against any abnormalities which could reasonably be expected to occur in the course of system operation is presented.