This standard covers the application of gapped silicon-carbide surge arresters (see ANSI/IEEE Std C62.1-1984 [1])to safeguard electric power equipment against the hazards of abnormally high voltage surges of various origins. Such over voltages may cause flash-overs and serious damage to equipment, thereby jeopardizing the supply of power to users. It is essential to prevent this by the proper coordination of surge protective devices with the insulation strength of the protected equipment. The subject is a broad one with many ramifications, and it would require a volume of considerable bulk to explain all possible cases in detail. Section 3 of this standard covers the basic cases for stations used to supply and switch electric power transmission, subtransmission, or distribution feeders. Information is included in Section 4 on application of arresters for protection of overhead distribution systems, both open-wire and spacer cable; underground system cables; all distribution transformers; and other electric distribution equipment. Step-by-step directions toward proper solutions for various applications are provided. For many cases the prescribed steps are adequate. Complex situations or special situations requiring study by experienced engineers are described, but specific solutions may not be given. These procedures are based on theoretical studies, test results, and experience.