Standards/Codes
Surge arresters are designed and tested per ANSI/IEEE C62.1, Standard for Gapped Silicone-Carbide Surge Arresters for AC Power Circuits, for the gapped type and ANSI/IEEE C62.11, Standard for Metal-Oxide Surge Arresters for Alternating Current Systems, for the gapless type. Article 280 of the NFPA70/National Electrical Code governs surge arrester’s general requirements, installation requirements and connection requirements. In addition, surge arresters are listed by UL under the category of, Surge Arresters (OWHX), and other NRTLs (Nationally Recognized Testing Laboratories) using the applicable sections of the ANSI/IEEE standards noted above.
Selection and Application
The primary objective in arrester application is to select the lowest rated surge arrester that will provide adequate protection of the equipment insulation and be rated such that it will have a satisfactory service life when connected to the power system. An arrester of the minimum practical rating is preferred because it provides the highest margin of protection for the equipment insulation system. There is a fine line between protection and service life of a surge arrester. Higher arrester ratings will increase the capability of the arrester to survive on a specific power system but reduce the margin of protection provided for the insulation level of the equipment it is protecting. Therefore, the reader should consider both issues of arrester survival and equipment protection when selecting surge arresters.