{"id":4142,"date":"2023-01-05T14:05:39","date_gmt":"2023-01-05T13:05:39","guid":{"rendered":"https:\/\/www.gt-engineering.it\/normative-tecniche\/%tipologia_normativa%\/appendix-d-bus-bar-system\/"},"modified":"2025-03-31T08:47:59","modified_gmt":"2025-03-31T07:47:59","slug":"appendix-d-bus-bar-system","status":"publish","type":"normativa_tecnica","link":"https:\/\/www.gt-engineering.it\/en\/technical-standards\/ul-and-nfpa-standards\/ul-508a\/appendix-d-bus-bar-system\/","title":{"rendered":"Appendix D: Bus Bar System"},"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:flex-row\">\n\n    \n\n                    <div \n                class=\"order-2 relative w-full md:w-1\/2\"\n            >\n                <div\n                    class=\"pt-6 space-y-6 w-full md:pt-0 md:space-y-4 lg:space-y-8 xl:space-y-9  md:pl-12 xl:pl-24\"\n                >\n                    \n        <div                class=\"m-headings\"\n            >\n    \n    \n<h4 class=\"a-heading text-primary font-heading text-2xl lg:text-3xl xl:text-4xl font-normal mt-2 first:mt-0\">\n                    APPENDIX D    <\/h4>\n        <\/div>\n    \n<div class=\"a-text font-text text-base normal mt-8 first:mt-0 space-y-4\">\n    <p>Annex D was introduced in the <a href=\"https:\/\/www.gt-engineering.it\/en\/technical-standards\/ul-and-nfpa-standards\/ul-508a\/april-2020-update\/\"><span style=\"text-decoration: underline; color: #008c66;\">april 2020 version of UL 508A<\/span><\/a>. It clarifies what was previously common but not formally correct practice.<\/p>\n<p>A manufacturer of electrical automation panels is not required to use a certified busbar system or to subject it to short-circuit tests, provided that it complies with Table G3.1 of UL 891 (called Table D3.1 in UL 508A).<\/p>\n<p>This table is now included in the new annex, which formally makes this practice possible.<\/p>\n<\/div>                <\/div>\n            <\/div>\n        \n                    <div\n                class=\"h-auto order-1 mb-8 md:mb-0   overflow-hidden shadow-content-image w-full md:w-1\/2\"\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\/01\/appendixdul508a-150x150.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 300px)\"\r\n                                width=\"300\"\r\n                                height=\"195\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/appendixdul508a-300x195.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 768px)\"\r\n                                width=\"768\"\r\n                                height=\"498\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/appendixdul508a-768x498.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 1024px)\"\r\n                                width=\"1024\"\r\n                                height=\"664\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/appendixdul508a-1024x664.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                            <img\r\n                            class=\"a-image transparent border-image h-auto  w-full mx-auto\"\r\n                                                        srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/appendixdul508a.png.webp\"\r\n                                                        title=\"appendixdul508a\"\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>\n        <\/section>\n\n    \n\n\n\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:flex-row\">\n\n    \n\n                    <div \n                class=\"order-2 relative w-full md:w-1\/2\"\n            >\n                <div\n                    class=\"pt-6 space-y-6 w-full md:pt-0 md:space-y-4 lg:space-y-8 xl:space-y-9  md:pl-12 xl:pl-24\"\n                >\n                    \n        <div                class=\"m-headings\"\n            >\n    \n    \n<h4 class=\"a-heading text-primary font-heading text-2xl lg:text-3xl xl:text-4xl font-normal mt-2 first:mt-0\">\n                    \u201cFACE TO FACE\u201d OR \u201cEDGE TO EDGE\u201d ARRANGEMENT    <\/h4>\n        <\/div>\n    \n<div class=\"a-text font-text text-base normal mt-8 first:mt-0 space-y-4\">\n    <p>The table, in addition to giving specifications regarding the maximum thickness of the busbar, the maximum current and the maximum nominal voltage, distinguishes between busbars mounted in a \u201cFace to Face\u201d or \u201cEdge to Edge\u201d arrangement.<\/p>\n<p>For example, in the case of busbars arranged \u201cEdge to Edge\u201d, if the distance between the insulators is not greater than 533 mm, provided that the size of the busbar complies with table D3.1, and the rest of the architecture complies with SUPPLEMENT SB (with all devices having SCCR equal to 50 kA), the switchgear can be declared with SCCR = 50 kA.<\/p>\n<\/div>                <\/div>\n            <\/div>\n        \n                    <div\n                class=\"h-auto order-1 mb-8 md:mb-0   overflow-hidden shadow-content-image w-full md:w-1\/2\"\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\/01\/edgetoedge-150x150.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 300px)\"\r\n                                width=\"300\"\r\n                                height=\"122\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/edgetoedge-300x122.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 768px)\"\r\n                                width=\"768\"\r\n                                height=\"311\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/edgetoedge-768x311.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 1024px)\"\r\n                                width=\"1024\"\r\n                                height=\"415\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/edgetoedge-1024x415.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                            <img\r\n                            class=\"a-image transparent border-image h-auto  w-full mx-auto\"\r\n                                                        srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2023\/01\/edgetoedge.png.webp\"\r\n                                                        title=\"edgetoedge\"\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>\n        <\/section>\n\n    \n","protected":false},"excerpt":{"rendered":"<p>&#8230;<\/p>\n","protected":false},"author":1,"featured_media":4023,"parent":4095,"menu_order":12,"template":"","meta":{"_acf_changed":false,"footnotes":""},"normative-tecniche":[59],"class_list":["post-4142","normativa_tecnica","type-normativa_tecnica","status-publish","has-post-thumbnail","hentry","tipologia_normativa-ul-and-nfpa-standards"],"acf":{"sottotitolo":"","allegati":null},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.2 - 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