Foreword?Live-line maintenance of transmission lines began in the early 1920s and developed into a major working practice as the transmission systems were expanded and the voltages increased. In the 1950s@ when the transmission line voltage exceeded 300 kilovolts phase-to-phase@ the use of fiberglass to replace wooden tools made a significant change in the industry. Economic conditions prohibited the construction and operation of redundant lines@ and the need for live-line maintenance of transmission line increased rapidly. During the 1950s and 1960s@ several papers were written regarding the safety aspects of live-line maintenance. In the early 1970s@ the IEEE Transmission and Distribution Committee recognized the need to consolidate information on live-line maintenance@ and thus@ a task group was formed to write a guide. The task group later became the Engineering in Safety@ Maintenance@ and Operation of Lines Subcommittee (ESMOL). This guide was started in the late 1970s and was published in 1986 on a trial-use basis. In 1987@ the guide was released as a full-use ANSI/IEEE Standard. In 1990@ and again in 1995@ the ESMOL Subcommittee started revisions to the guide to bring it up to the current state of the art and into conformance with other international standards issued in recent years. The ESMOL Subcommittee has added sections from other ESMOL-sponsored standards in this edition to expand the scope of the standard to cover more of the industryapos;s needs. During the original development of the guide@ it was not intended that it would be used as a document to establish government regulations. However@ since its publication in 1986@ several government regulatory agencies have used the guide in their rule making. This edition of the guide includes revisions that make it more compatible for use in governmental regulations. ScopeThis guide provides general recommendations for performing maintenance work on energized power lines. It is not intended to include all of the proven practical methods and procedures; however@ these selected comprehensive recommendations are based on sound engineering principles@ engineering safety considerations@ and field experience by many utilities. Included are technical explanations as required to cover certain laboratory testing of tools and equipment@ in-service inspection@ maintenance and care of tools and equipment@ and work methods for the maintenance of energized lines and for persons working in the vicinity of energized lines.