{"id":3099,"date":"2024-08-26T20:43:33","date_gmt":"2024-08-26T20:43:33","guid":{"rendered":"https:\/\/workhouse.sweetdishy.com\/?p=3099"},"modified":"2024-08-26T20:43:33","modified_gmt":"2024-08-26T20:43:33","slug":"spacings","status":"publish","type":"post","link":"https:\/\/workhouse.sweetdishy.com\/index.php\/2024\/08\/26\/spacings\/","title":{"rendered":"Spacings"},"content":{"rendered":"\n<p id=\"P0560\">Even the lowest-voltage systems require some consideration for the electrical clearances between conductors of different voltage. Standards have been developed by the Canadian Standards Association (CSA), Institute of Electrical and Electronics Engineers (IEEE), National Electrical Manufacturers Association (NEMA), and Underwriter\u2019s Laboratories (UL). These standards cover everything from PC boards to high-voltage switchgear.<\/p>\n\n\n\n<p id=\"P0570\">Spacings are generally considered in two classes:&nbsp;<em>strike<\/em>, the clearance through air paths, and&nbsp;<em>creep<\/em>, the clearance along insulating surfaces. Whereas the strike capability of an air path between spherical conductors may be much larger then the standards allow, the standards recognize the imperfect world of sharp-edged conductors, conductor movement on faults, voltage transients, and safety margins. Similarly, the creep standards recognize that insulating surfaces may become contaminated by conductive dust or moisture.<\/p>\n\n\n\n<p id=\"P0580\">Understanding these standards is especially important in applying medium-voltage transformers that are directly connected to customer switchgear. The switchgear is the first line of defense and must cope with lightning and switching transient voltages, but it will pass along these transients to connected equipment. Unless equipment connected to customer switchgear is protected by auxiliary arresters and\/or surge capacitors, it\u00a0must meet the same standards as the switchgear itself.\u00a0Table 15.1\u00a0is taken from the Westinghouse document, \u201cElectrical Clearances for Switchgear,\u201d and, although some years old, it is typical of the several extant standards.<\/p>\n\n\n\n<p>Table 15.1<\/p>\n\n\n\n<p>: Switchgear electrical clearance standards<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/learning.oreilly.com\/api\/v2\/epubs\/urn:orm:book:9781856175289\/files\/images\/T000159tabT0010.jpg\" alt=\"Image\"\/><\/figure>\n\n\n\n<p id=\"P0590\">The insulated conductors include extruded insulations, insulating boots, and high-voltage taping. The standards recognize that these insulating materials may degrade with continued exposure to high voltages.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Even the lowest-voltage systems require some consideration for the electrical clearances between conductors of different voltage. Standards have been developed by the Canadian Standards Association (CSA), Institute of Electrical and Electronics Engineers (IEEE), National Electrical Manufacturers Association (NEMA), and Underwriter\u2019s Laboratories (UL). These standards cover everything from PC boards to high-voltage switchgear. Spacings are generally [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":3100,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[420],"tags":[],"class_list":["post-3099","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-power-electronics"],"jetpack_featured_media_url":"https:\/\/workhouse.sweetdishy.com\/wp-content\/uploads\/2024\/08\/images-41.jpeg","_links":{"self":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/3099","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/comments?post=3099"}],"version-history":[{"count":1,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/3099\/revisions"}],"predecessor-version":[{"id":3101,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/3099\/revisions\/3101"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media\/3100"}],"wp:attachment":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media?parent=3099"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/categories?post=3099"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/tags?post=3099"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}