{"id":48195,"date":"2025-06-27T15:36:45","date_gmt":"2025-06-27T14:36:45","guid":{"rendered":"https:\/\/www.gt-engineering.it\/?post_type=approfondimento&#038;p=48195"},"modified":"2025-07-09T07:25:39","modified_gmt":"2025-07-09T06:25:39","slug":"la-courbe-de-securite-et-le-systeme-tn","status":"publish","type":"approfondimento","link":"https:\/\/www.gt-engineering.it\/fr\/approfondissement\/securite-electrique\/la-courbe-de-securite-et-le-systeme-tn\/","title":{"rendered":"La courbe de s\u00e9curit\u00e9 et le syst\u00e8me TN"},"content":{"rendered":"\n\n    \n        <section\n            data-name=\"Contenuto testuale con immagine\"\n            class=\"bow-gte-testo-media u-spacer-none\"\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\/2025\/06\/Immagine1-150x150.jpg.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 300px)\"\r\n                                width=\"300\"\r\n                                height=\"162\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Immagine1-300x162.jpg.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 643px)\"\r\n                                width=\"643\"\r\n                                height=\"348\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Immagine1.jpg.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 643px)\"\r\n                                width=\"643\"\r\n                                height=\"348\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Immagine1.jpg.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\/2025\/06\/Immagine1.jpg.webp\"\r\n                                                        title=\"Immagine1\"\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>Tout le monde sait que le courant \u00e9lectrique est dangereux, mais comment d\u00e9terminer quel est le seuil critique ?<\/p>\n<p>La r\u00e9glementation en mati\u00e8re de s\u00e9curit\u00e9 \u00e9lectrique vient \u00e0 notre secours. Il s\u2019agit de la s\u00e9rie de normes <em>IEC 60479-1:\u00a0 Effets du courant sur l&rsquo;homme et les animaux domestiques<\/em>. La norme traite de la dangerosit\u00e9 du<strong> courant continu (DC) et alternatif (AC).<\/strong> Commen\u00e7ons par distinguer ces deux types de courant et comprendre pourquoi ils sont dangereux pour le corps humain :<\/p>\n<ul>\n<li><strong>Le courant alternatif (AC)<\/strong> est utilis\u00e9 partout : dans les habitations, les bureaux ou les usines. Il a une forme sinuso\u00efdale, c\u2019est-\u00e0-dire que la tension et le courant augmentent et diminuent continuellement et r\u00e9guli\u00e8rement, avec une fr\u00e9quence de 50 Hz (60 Hz en Am\u00e9rique du Nord et dans quelques autres pays).\u00a0Le c\u0153ur humain fonctionne avec un rythme propre, induit par des impulsions \u00e9lectriques d\u2019environ 1 Hz. Lorsqu\u2019une personne re\u00e7oit une d\u00e9charge \u00e9lectrique, un courant de 50 Hz traverse le corps. Dans ce cas, le c\u0153ur se synchronise avec la fr\u00e9quence du r\u00e9seau et ne bat plus \u00e0 son rythme naturel. Autrement dit, le rythme du c\u0153ur est domin\u00e9 par celui du courant, ce qui perturbe son fonctionnement et entra\u00eene des vibrations au lieu du pompage normal (fibrillation cardiaque).<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<ul>\n<li><strong>Le courant continu (DC)<\/strong>, quant \u00e0 lui, est pr\u00e9sent dans les batteries, les v\u00e9hicules \u00e9lectriques, les installations photovolta\u00efques et bien d&rsquo;autres applications. Bien qu\u2019il ait une pulsation, il est moins susceptible de provoquer une fibrillation, mais il augmente le risque d\u2019arr\u00eat cardiaque, car il ne modifie pas le rythme cardiaque, mais maintient le muscle cardiaque contract\u00e9. Le courant continu est consid\u00e9r\u00e9 comme moins dangereux, car il provoque des dommages \u00e0 des tensions plus \u00e9lev\u00e9es que le courant alternatif. \u00c0 cet \u00e9gard, on peut rappeler la c\u00e9l\u00e8bre \u00ab <strong>guerre des courants<\/strong> \u00bb, qui opposait <strong>Thomas Edison<\/strong> \u00e0 <strong>Nikola Tesla<\/strong> \u00e0 la fin du XIXe si\u00e8cle.<\/li>\n<\/ul>\n<\/div>            <\/div>\n        \n        \n                <div class=\"clear-both\"><\/div>\n        \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-2xs\"\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                    <div class=\"mb-6 relative w-full md:mb-4 lg:mb-8 xl:mb-9\">\n                \n        <div                class=\"m-headings\"\n            >\n    \n    \n<h2 class=\"a-heading text-primary font-heading text-lg lg:text-xl font-normal mt-2 first:mt-0\">\n                    Courbes pour le danger du courant traversant le corps    <\/h2>\n        <\/div>\n                <\/div>\n        \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>Pour repr\u00e9senter graphiquement la dangerosit\u00e9 du courant, des diagrammes ont \u00e9t\u00e9 \u00e9labor\u00e9s, permettant d\u2019identifier les valeurs de courant en fonction de la dur\u00e9e d\u2019exposition et des dommages qu\u2019ils peuvent causer au corps humain. Il existe des graphiques pour le courant alternatif et continu.<\/p>\n<\/div>            <\/div>\n        \n        \n                <div class=\"clear-both\"><\/div>\n        \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-none\"\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\/2025\/06\/Immagine2-150x150.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=\"199\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Immagine2-300x199.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 643px)\"\r\n                                width=\"643\"\r\n                                height=\"427\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Immagine2.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 643px)\"\r\n                                width=\"643\"\r\n                                height=\"427\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Immagine2.png.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\/2025\/06\/Immagine2.png.webp\"\r\n                                                        title=\"Immagine2\"\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>Ces diagrammes sont divis\u00e9s en zones, auxquelles sont associ\u00e9s diff\u00e9rents effets :<\/p>\n<ul>\n<li><strong>Zone<\/strong> <strong>1<\/strong> : aucune r\u00e9action (&lt; 0,5 mA).<\/li>\n<li><strong>Zone 2<\/strong> : aucun effet physiologique important.<\/li>\n<li><strong>Zone 3<\/strong> : effets pathologiques r\u00e9versibles, comme la contraction musculaire.<\/li>\n<li><strong>Zone 4<\/strong> : zone dangereuse avec risque probable de fibrillation.<\/li>\n<\/ul>\n<p>La <strong>zone 4<\/strong> est elle-m\u00eame divis\u00e9e en trois sous-zones :<\/p>\n<ul>\n<li><strong>Sous la courbe C1<\/strong> : pas de fibrillation attendue.<\/li>\n<li><strong>Sous C2<\/strong> : risque de fibrillation de 5 %.<\/li>\n<li><strong>Sous C3<\/strong> : risque de fibrillation de 50 %.<\/li>\n<\/ul>\n<p><strong>Le graphique ci-joint est valable pour le courant alternatif (AC).<\/strong><\/p>\n<\/div>            <\/div>\n        \n        \n                <div class=\"clear-both\"><\/div>\n        \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-none\"\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-right ml-6 md:ml-4 lg:ml-8 xl:ml-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\/2025\/06\/Immagine3-150x150.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=\"197\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Immagine3-300x197.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=\"504\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Immagine3-768x504.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=\"672\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Immagine3-1024x672.png.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\/2025\/06\/Immagine3.png.webp\"\r\n                                                        title=\"Immagine3\"\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><strong>Le graphique pour le courant continu (DC)<\/strong>, \u00e0 droite, montre que<strong> le courant continu est environ quatre fois moins dangereux que le courant alternatif<\/strong> (pour des valeurs faibles). Par exemple, la courbe C1 commence \u00e0 40 mA en AC, alors qu\u2019en DC, elle commence \u00e0 160 mA.<\/p>\n<\/div>            <\/div>\n        \n        \n                <div class=\"clear-both\"><\/div>\n        \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-2xs\"\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                    <div class=\"mb-6 relative w-full md:mb-4 lg:mb-8 xl:mb-9\">\n                \n        <div                class=\"m-headings\"\n            >\n    \n    \n<h2 class=\"a-heading text-primary font-heading text-lg lg:text-xl font-normal mt-2 first:mt-0\">\n                    La courbe de s\u00e9curit\u00e9 actuelle    <\/h2>\n        <\/div>\n                <\/div>\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\/2025\/06\/Senza-titolo-1-150x150.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=\"286\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Senza-titolo-1-300x286.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 380px)\"\r\n                                width=\"380\"\r\n                                height=\"362\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Senza-titolo-1.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 380px)\"\r\n                                width=\"380\"\r\n                                height=\"362\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Senza-titolo-1.png.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\/2025\/06\/Senza-titolo-1.png.webp\"\r\n                                                        title=\"Senza titolo\"\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>En ce qui concerne la dangerosit\u00e9 du courant alternatif, \u00e0 partir du graphique ci-dessus, dans les ann\u00e9es 80, une limite a \u00e9t\u00e9 d\u00e9finie au-del\u00e0 de laquelle le courant devient dangereux en fonction du temps. Cette limite, indiqu\u00e9e par une courbe en pointill\u00e9s dans l&rsquo;image ci-contre, est commun\u00e9ment appel\u00e9e <strong>courbe de s\u00e9curit\u00e9 pour le courant alternatif.<\/strong><\/p>\n<p>Les courbes \u00e0 gauche et \u00e0 droite de la courbe en pointill\u00e9s correspondent respectivement \u00e0 la courbe \u201cb\u201d et \u00e0 la courbe \u201cc1\u201d du graphique pr\u00e9c\u00e9dent.<\/p>\n<p>Cette courbe est essentielle pour le calibrage des dispositifs de protection <strong>destin\u00e9s \u00e0 prot\u00e9ger les personnes contre les contacts indirects.<\/strong> Par exemple, avec un courant de 200 mA, le temps maximal d\u2019ouverture du circuit doit \u00eatre d\u2019environ 150 ms pour garantir la s\u00e9curit\u00e9 r\u00e9glementaire.<\/p>\n<\/div>            <\/div>\n        \n        \n                <div class=\"clear-both\"><\/div>\n        \n\n    <\/div>\n        <\/section>\n\n    \n\n\n\n\n    \n        \n    \n\n\n\n\n    \n        <section\n            data-name=\"Contenuto testuale con immagine\"\n            class=\"bow-gte-testo-media u-spacer-none\"\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                    <div class=\"mb-6 relative w-full md:mb-4 lg:mb-8 xl:mb-9\">\n                \n        <div                class=\"m-headings\"\n            >\n    \n    \n<h2 class=\"a-heading text-primary font-heading text-lg lg:text-xl font-normal mt-2 first:mt-0\">\n                    Syst\u00e8me TN et temps d&rsquo;ouverture maximal de la protection    <\/h2>\n        <\/div>\n                <\/div>\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\/2025\/06\/Screenshot-2025-06-27-163405-150x150.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=\"174\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-27-163405-300x174.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=\"445\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-27-163405-768x445.png.webp\"\r\n                                type=\"image\/webp\"\r\n                            \/>\r\n                                                                                <source\r\n                                media=\"(max-width: 955px)\"\r\n                                width=\"955\"\r\n                                height=\"553\"\r\n                                srcset=\"https:\/\/www.gt-engineering.it\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-27-163405.png.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\/2025\/06\/Screenshot-2025-06-27-163405.png.webp\"\r\n                                                        title=\"Screenshot 2025-06-27 163405\"\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>Le sch\u00e9ma ci-contre montre la mise \u00e0 la terre des masses dans un syst\u00e8me TN (terre-neutre), g\u00e9n\u00e9ralement utilis\u00e9 dans le secteur industriel, contrairement au syst\u00e8me TT (terre-terre), plus courant dans le secteur r\u00e9sidentiel.<\/p>\n<p><strong>Dans un syst\u00e8me TT<\/strong>, les masses sont reli\u00e9es \u00e0 une \u00ab terre locale \u00bb qui est elle-m\u00eame reli\u00e9e au neutre du transformateur. <strong>La boucle de d\u00e9faut inclut la terre, en plus des conducteurs.<\/strong><\/p>\n<p><strong>Dans un syst\u00e8me TN<\/strong>, en revanche, les masses sont connect\u00e9es directement au neutre du transformateur. La boucle de d\u00e9faut ne comprend que des conducteurs en cuivre. Ainsi, un d\u00e9faut \u00e0 la terre \u00e0 faible imp\u00e9dance g\u00e9n\u00e8re un courant de d\u00e9faut tr\u00e8s \u00e9lev\u00e9.<\/p>\n<p>Cela montre que la mise \u00e0 la terre d\u2019un appareil \u00e9lectrique sert <strong>\u00e0 cr\u00e9er une boucle de d\u00e9faut<\/strong>, normalement inactif (aucun courant ne la traverse). En cas de d\u00e9faut, ce circuit est parcouru par un courant important (dans le cas d\u2019un syst\u00e8me TN), ce qui active la protection magn\u00e9tothermique ou diff\u00e9rentielle, interrompant le circuit.<\/p>\n<p>En r\u00e9sum\u00e9, la protection diff\u00e9rentielle ou magn\u00e9tothermique est activ\u00e9e lorsqu\u2019un courant de d\u00e9faut traverse le circuit. Ce courant n\u2019est normalement pas pr\u00e9sent sur le conducteur de terre.<\/p>\n<p><strong>Lors d\u2019un d\u00e9faut<\/strong>, le courant passe par le conducteur de terre (dans un syst\u00e8me TN avec une faible imp\u00e9dance), ce qui permet une d\u00e9tection rapide et une ouverture du circuit dans un temps tr\u00e8s court. Cela garantit que la personne en contact avec une masse m\u00e9tallique mise sous tension accidentellement ne soit expos\u00e9e au courant que pendant une tr\u00e8s courte dur\u00e9e, conforme aux limites indiqu\u00e9es par la courbe de s\u00e9curit\u00e9.<\/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>Tout le monde sait que le courant \u00e9lectrique est dangereux, mais comment d\u00e9terminer quel est le seuil critique ?<br \/>\nLa r\u00e9glementation en mati\u00e8re de s\u00e9curit\u00e9 \u00e9lectrique vient \u00e0 notre secours. Il s\u2019agit de la s\u00e9rie de normes CEI 60479-1 : Effets du courant sur les \u00eatres humains et les animaux d\u2019\u00e9levage.<\/p>\n","protected":false},"author":2,"featured_media":48024,"parent":0,"menu_order":8,"template":"","meta":{"_acf_changed":false,"footnotes":""},"tipologia_approfondimento":[158],"class_list":["post-48195","approfondimento","type-approfondimento","status-publish","has-post-thumbnail","hentry","tipologia_approfondimento-securite-electrique"],"acf":{"sottotitolo":"","allegati":null},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.2 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>La courbe de s\u00e9curit\u00e9 et le syst\u00e8me TN - 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\/approfondissement\/securite-electrique\/la-courbe-de-securite-et-le-systeme-tn\/\" \/>\n<meta property=\"og:locale\" content=\"fr_FR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"La courbe de s\u00e9curit\u00e9 et le syst\u00e8me TN - Gt-Engineering\" \/>\n<meta property=\"og:description\" content=\"Tout le monde sait que le courant \u00e9lectrique est dangereux, mais comment d\u00e9terminer quel est le seuil critique ? 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