{"id":39547,"date":"2023-01-05T14:16:14","date_gmt":"2023-01-05T13:16:14","guid":{"rendered":"https:\/\/www.gt-engineering.it\/?post_type=normativa_tecnica&#038;p=39547"},"modified":"2025-08-18T15:43:12","modified_gmt":"2025-08-18T14:43:12","slug":"ul-508a-circuits-de-commande","status":"publish","type":"normativa_tecnica","link":"https:\/\/www.gt-engineering.it\/fr\/reglements-techniques\/normes-americaine\/ul-508a\/ul-508a-circuits-de-commande\/","title":{"rendered":"UL 508A &#8211; Circuits de commande"},"content":{"rendered":"\n\n    \n        <section\n            data-name=\"Contenuto testuale con immagine\"\n            class=\"bow-gte-testo-media u-spacer-base\"\n            id=\"\"\n        >\n            \n<div class=\"o-text-media px-side-spacer sm:px-side-spacer-sm lg:px-side-spacer-tablet 2xl:px-side-spacer-desktop flex flex-wrap items-start md:block\">\n\n    \n        \n                    <div\n                class=\"h-auto mb-6 md:mb-4 lg:mb-8 xl:mb-9 float-left mr-6 md:mr-4 lg:mr-8 xl:mr-9  overflow-hidden shadow-content-image w-full md:w-1\/3\"\n            >\n                \r\n\r\n    \r\n        \r\n            \r\n                \r\n                    <picture\r\n                        class=\"\"\r\n                                            >\r\n                                                                                                        <source\r\n                                media=\"(max-width: 150px)\"\r\n                                width=\"150\"\r\n                                height=\"150\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/07\/branch_feeder.png-1-150x150.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 300px)\"\r\n                                width=\"300\"\r\n                                height=\"260\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/07\/branch_feeder.png-1-300x260.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 768px)\"\r\n                                width=\"768\"\r\n                                height=\"665\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/07\/branch_feeder.png-1-768x665.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 1024px)\"\r\n                                width=\"1024\"\r\n                                height=\"886\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/07\/branch_feeder.png-1-1024x886.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                            <img\r\n                            class=\"a-image transparent border-image h-auto  w-full\"\r\n                                                        srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/07\/branch_feeder.png-1.webp\"\r\n                                                        title=\"branch_feeder.png\"\r\n                                                        type=\"image\/webp\"\r\n                        \/>\r\n                    <\/picture>\r\n\r\n                \r\n\r\n                    \r\n    \r\n            <\/div>\n        \n                    <div class=\"relative w-full\">\n                \n<div class=\"a-text font-text text-base normal mt-8 first:mt-0 space-y-4\">\n    <p>Selon l&rsquo;article 100 du NEC, tout circuit qui contr\u00f4le un autre circuit par l&rsquo;interm\u00e9diaire d&rsquo;un relais ou d&rsquo;un dispositif \u00e9quivalent peut \u00eatre consid\u00e9r\u00e9 comme un circuit de contr\u00f4le. Ce circuit peut \u00eatre en <strong>amont<\/strong> ou en<strong> aval<\/strong> du dispositif de <strong>protection du circuit de d\u00e9rivation (BCPD).<\/strong><\/p>\n<p>Le circuit de commande est g\u00e9n\u00e9ralement aliment\u00e9 par un transformateur qui abaisse la tension en dessous de <strong>600 V AC<\/strong> et n&rsquo;a pas de limites de courant (UL508A). D&rsquo;autre part, selon la norme NFPA 79, la tension maximale ne doit pas d\u00e9passer <strong>120 V CA<\/strong> ou <strong>250 V CC<\/strong> (9.1.2.2). En outre, les autotransformateurs ne peuvent pas \u00eatre utilis\u00e9s. Le transformateur de commande n&rsquo;est pas n\u00e9cessaire si<\/p>\n<ul>\n<li>la tension d&rsquo;alimentation est d\u00e9j\u00e0 de 120 V AC ;<\/li>\n<li>le courant de court-circuit maximal est inf\u00e9rieur \u00e0 1000 A.<\/li>\n<\/ul>\n<p>En ce qui concerne les dispositifs de protection qui peuvent \u00eatre utilis\u00e9s dans un circuit de commande :<\/p>\n<ul>\n<li>si le circuit de commande est en aval d&rsquo;un BCPD, <strong>des protections suppl\u00e9mentaires<\/strong> (UL1077) peuvent \u00eatre utilis\u00e9es, car, en cas de court-circuit, le BCPD en amont est cens\u00e9 pouvoir interrompre les courants de d\u00e9faut ;<\/li>\n<li>si le circuit de commande est en amont d&rsquo;un BPCD, un disjoncteur UL489 ou un fusible appropri\u00e9 UL248 est n\u00e9cessaire.<\/li>\n<\/ul>\n<p>Le transformateur de commande peut \u00eatre prot\u00e9g\u00e9 <strong>uniquement du c\u00f4t\u00e9 primaire<\/strong> (voir tableau<strong> 42.1<\/strong>) ou, pour \u00e9viter les d\u00e9clenchements intempestifs, <strong>\u00e0 la fois du c\u00f4t\u00e9 primaire et du c\u00f4t\u00e9 secondaire (tableau 42.2).<\/strong><\/p>\n<\/div>            <\/div>\n        \n        \n                <div class=\"clear-both\"><\/div>\n        \n\n    <\/div>\n        <\/section>\n\n    \n","protected":false},"excerpt":{"rendered":"<p>Selon l&rsquo;article 100 du NEC, tout circuit qui contr\u00f4le un autre circuit par l&rsquo;interm\u00e9diaire d&rsquo;un relais ou d&rsquo;un dispositif \u00e9quivalent peut \u00eatre consid\u00e9r\u00e9 comme un circuit de contr\u00f4le. Ce circuit peut \u00eatre en amont ou en aval du dispositif de protection du circuit de d\u00e9rivation (BCPD).<\/p>\n","protected":false},"author":182,"featured_media":39548,"parent":39459,"menu_order":9,"template":"","meta":{"_acf_changed":false,"footnotes":""},"normative-tecniche":[167],"class_list":["post-39547","normativa_tecnica","type-normativa_tecnica","status-publish","has-post-thumbnail","hentry","tipologia_normativa-normes-americaine"],"acf":{"sottotitolo":"Alimentation en tension, courant de court-circuit et dispositifs de contr\u00f4le","allegati":null},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.2 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>UL 508A - Circuits de commande - Gt-Engineering<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.gt-engineering.it\/fr\/reglements-techniques\/normes-americaine\/ul-508a\/ul-508a-circuits-de-commande\/\" \/>\n<meta property=\"og:locale\" content=\"fr_FR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"UL 508A - Circuits de commande - Gt-Engineering\" \/>\n<meta property=\"og:description\" content=\"Selon l&#039;article 100 du NEC, tout circuit qui contr\u00f4le un autre circuit par l&#039;interm\u00e9diaire d&#039;un relais ou d&#039;un dispositif \u00e9quivalent peut \u00eatre consid\u00e9r\u00e9 comme un circuit de contr\u00f4le. 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