{"id":4587,"date":"2026-09-21T12:30:37","date_gmt":"2026-09-21T04:30:37","guid":{"rendered":"https:\/\/cnkuangya.com\/?p=4587"},"modified":"2026-09-21T12:30:43","modified_gmt":"2026-09-21T04:30:43","slug":"can-an-spd-work-without-ground","status":"publish","type":"post","link":"https:\/\/cnkuangya.com\/fr\/blog\/can-an-spd-work-without-ground\/","title":{"rendered":"Un parafoudre peut-il fonctionner sans mise \u00e0 la terre ? 7 faits essentiels sur la mise \u00e0 la terre"},"content":{"rendered":"<p class=\"wp-block-paragraph\">Un parafoudre peut-il fonctionner sans terre ? La r\u00e9ponse techniquement correcte est : <strong>parfois, un mode de protection sp\u00e9cifique peut fonctionner sans chemin PE direct, mais cela ne signifie pas que le syst\u00e8me complet de protection contre les surtensions est correctement prot\u00e9g\u00e9 sans mise \u00e0 la terre ou liaison \u00e9quipotentielle.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Un parafoudre ne se contente pas d\u201c\u201d envoyer chaque surtension dans le sol \u00bb. Il limite la tension entre des conducteurs d\u00e9finis en devenant conducteur lorsque la tension aux bornes d'un mode de protection d\u00e9passe sa plage de fonctionnement. Selon la conception du parafoudre, ces modes de protection peuvent inclure phase-neutre (L\u2013N), phase-terre (L\u2013PE), neutre-terre (N\u2013PE), ou DC+\/DC\u2212 vers la terre (PE).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C'est pourquoi la question est plus complexe qu'un simple \u201c mis \u00e0 la terre ou non \u201d. Les v\u00e9ritables questions d'ing\u00e9nierie sont :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Quels conducteurs sont prot\u00e9g\u00e9s ?<\/li>\n\n\n\n<li>Quels modes de protection existent \u00e0 l'int\u00e9rieur du parafoudre ?<\/li>\n\n\n\n<li>Quel est le r\u00e9gime de neutre utilis\u00e9 : TN, TT, IT ou une configuration photovolta\u00efque CC ?<\/li>\n\n\n\n<li>Le conducteur de protection (PE) est-il pr\u00e9sent et correctement raccord\u00e9 ?<\/li>\n\n\n\n<li>Quelle est la longueur des conducteurs de raccordement du parafoudre (SPD) ?<\/li>\n\n\n\n<li>Le sch\u00e9ma de c\u00e2blage est-il approuv\u00e9 par le fabricant du parafoudre ?<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Si le probl\u00e8me que vous tentez de r\u00e9soudre n'est pas li\u00e9 \u00e0 la mise \u00e0 la terre, mais \u00e0 la diff\u00e9rence entre une surtension transitoire et un probl\u00e8me de tension de plus longue dur\u00e9e, lisez d'abord <a href=\"https:\/\/cnkuangya.com\/fr\/blog\/does-an-spd-protect-against-overvoltage\/\">un parafoudre prot\u00e8ge-t-il contre les surtensions<\/a>. La mise \u00e0 la terre ne peut pas transformer un parafoudre en r\u00e9gulateur de tension ou en relais de surtension g\u00e9n\u00e9ral.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">R\u00e9ponse rapide : Un parafoudre peut-il fonctionner sans mise \u00e0 la terre ?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Un parafoudre peut-il fonctionner sans mise \u00e0 la terre ?<\/strong> Une meilleure r\u00e9ponse est : <strong>cela d\u00e9pend de ce que l'on entend par \u201c terre \u201d et du mode de protection du parafoudre concern\u00e9.<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Situation<\/th><th>Le parafoudre peut-il encore agir ?<\/th><th>Pr\u00e9occupation principale<\/th><\/tr><\/thead><tbody><tr><td>Mode de protection L-N sans connexion directe \u00e0 la terre (PE) dans ce mode<\/td><td>Potentiellement oui<\/td><td>Seule la tension en mode diff\u00e9rentiel entre L et N est limit\u00e9e<\/td><\/tr><tr><td>Mode de protection L-PE ou N-PE avec absence de PE<\/td><td>Non conforme \u00e0 l'usage pr\u00e9vu<\/td><td>Le chemin de protection con\u00e7u est incomplet ou incorrect<\/td><\/tr><tr><td>Le conducteur PE existe mais la connexion est excessivement longue<\/td><td>Le parafoudre (SPD) peut toujours fonctionner<\/td><td>Une tension inductive suppl\u00e9mentaire peut augmenter le niveau de protection install\u00e9<\/td><\/tr><tr><td>SPD inadapt\u00e9 au syst\u00e8me de mise \u00e0 la terre TN\/TT\/IT<\/td><td>Ne pas pr\u00e9sumer d'une protection correcte<\/td><td>Les modes de protection, les contraintes TOV et les conditions de d\u00e9faut peuvent ne pas correspondre au syst\u00e8me<\/td><\/tr><tr><td>Syst\u00e8me photovolta\u00efque CC flottant<\/td><td>Oui, avec une configuration de parafoudre PV correctement con\u00e7ue<\/td><td>\u201c CC flottant \u201d ne signifie pas que la mise \u00e0 la terre (PE) et la liaison \u00e9quipotentielle peuvent \u00eatre ignor\u00e9es<\/td><\/tr><tr><td>Absence de liaison efficace \/ connexion PE endommag\u00e9e<\/td><td>La protection peut \u00eatre gravement compromise<\/td><td>Des diff\u00e9rences de potentiel peuvent subsister entre les syst\u00e8mes conducteurs<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">La r\u00e8gle la plus importante est :<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\"><strong>Ne d\u00e9cidez pas si un parafoudre \u201c a besoin d'une mise \u00e0 la terre \u201d en regardant uniquement le nombre de modules. Identifiez le sch\u00e9ma de liaison \u00e0 la terre du syst\u00e8me et les modes de protection r\u00e9els du parafoudre.<\/strong><\/p>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">C'est pour cette m\u00eame raison qu'un parafoudre PV 2P ou 3P ne doit pas \u00eatre s\u00e9lectionn\u00e9 uniquement sur son apparence. Notre <a href=\"https:\/\/cnkuangya.com\/fr\/blog\/2p-vs-3p-dc-spd\/\">Guide comparatif des parafoudres DC 2P vs 3P<\/a> explique pourquoi le nombre de modules, les conducteurs prot\u00e9g\u00e9s, la connexion PE et les chemins de protection internes sont des concepts diff\u00e9rents.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">1. Que signifie \u201c terre \u201d dans une installation de parafoudre ?<\/h2>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-ground-pe-earth-bonding-explained-1024x576.jpg\" alt=\"SPD ground vs PE vs earth electrode vs equipotential bonding\" class=\"wp-image-4590\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-ground-pe-earth-bonding-explained-1024x576.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-ground-pe-earth-bonding-explained-300x169.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-ground-pe-earth-bonding-explained-768x432.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-ground-pe-earth-bonding-explained-1536x864.jpg 1536w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-ground-pe-earth-bonding-explained-18x10.jpg 18w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-ground-pe-earth-bonding-explained-600x338.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-ground-pe-earth-bonding-explained.jpg 1672w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Le PE, la liaison \u00e9quipotentielle, la borne principale de terre et le piquet de terre sont des \u00e9l\u00e9ments li\u00e9s du syst\u00e8me, mais ce ne sont pas la m\u00eame chose.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Avant de r\u00e9pondre \u00e0 la question \u201c un parafoudre peut-il fonctionner sans terre ? \u201d, nous devons d'abord d\u00e9finir ce que signifie r\u00e9ellement \u201c terre \u201d dans une installation \u00e9lectrique.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dans le langage courant, \u201c terre \u201d peut d\u00e9signer plusieurs choses diff\u00e9rentes :<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Terre de protection (PE)<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Le conducteur de protection (PE) est utilis\u00e9 pour relier les masses conductrices au syst\u00e8me de liaison \u00e9quipotentielle de l'installation \u00e9lectrique. De nombreux parafoudres incluent des modes de protection r\u00e9f\u00e9renc\u00e9s au PE.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Borne principale de terre ou barre de terre (PE)<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Il s'agit du point de liaison \u00e0 l'int\u00e9rieur de l'installation ou de l'ensemble de distribution o\u00f9 les conducteurs de protection sont connect\u00e9s conform\u00e9ment \u00e0 la conception du syst\u00e8me.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Prise de terre<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Une prise de terre assure une connexion conductrice entre l'installation \u00e9lectrique et la terre. Elle fait partie du syst\u00e8me de mise \u00e0 la terre, mais ne doit pas \u00eatre confondue avec la courte connexion PE entre un parafoudre (SPD) et la barre PE locale.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Liaison \u00e9quipotentielle<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">La liaison \u00e9quipotentielle r\u00e9duit les diff\u00e9rences de potentiel dangereuses entre les parties conductrices et les services. Lors d'un \u00e9v\u00e9nement de surtension, le contr\u00f4le des diff\u00e9rences de potentiel est souvent plus important que de consid\u00e9rer le courant de surtension comme empruntant un simple chemin \u201c vers un fil de terre \u201d.\u201d<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Relation entre neutre et terre<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">La relation entre le neutre et la terre d\u00e9pend du sch\u00e9ma de liaison \u00e0 la terre (r\u00e9gime de neutre). Les syst\u00e8mes TN, TT et IT n'utilisent pas la m\u00eame disposition neutre\/PE, ce qui explique pourquoi une m\u00eame topologie de parafoudre ne peut \u00eatre consid\u00e9r\u00e9e comme adapt\u00e9e partout.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Les conseils pratiques d'ABB sur les parafoudres distinguent les syst\u00e8mes de mise \u00e0 la terre TT, TN-C, TN-S et IT selon la mani\u00e8re dont le neutre d'alimentation et les terres des \u00e9quipements sont reli\u00e9s. Le choix du parafoudre doit donc \u00eatre coordonn\u00e9 avec le syst\u00e8me \u00e9lectrique r\u00e9el plut\u00f4t que bas\u00e9 sur une r\u00e8gle universelle de \u201c fil de terre \u201d.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">2. Comment un parafoudre utilise-t-il r\u00e9ellement le PE lors d'une surtension ?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Un parafoudre (SPD) typique est connect\u00e9 en parall\u00e8le avec le circuit plut\u00f4t que de transporter le courant de charge normal en s\u00e9rie. Dans des conditions normales, ses \u00e9l\u00e9ments de protection contre les surtensions restent dans un \u00e9tat \u00e0 haute imp\u00e9dance. Lorsque la tension aux bornes d'un mode de protection augmente suffisamment, le SPD devient conducteur et limite la tension en d\u00e9rivant le courant de surtension \u00e0 travers ce chemin de protection.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Si vous souhaitez d'abord obtenir l'explication au niveau du circuit, voir <a href=\"https:\/\/cnkuangya.com\/fr\/blog\/why-spd-connected-in-parallel\/\">pourquoi un SPD est connect\u00e9 en parall\u00e8le plut\u00f4t qu'en s\u00e9rie<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">L'expression <strong>\u201c d\u00e9river le courant de surtension vers la terre \u201d<\/strong> est utile comme explication simplifi\u00e9e, mais cela peut aussi cr\u00e9er un malentendu. Chaque surtension n'est pas trait\u00e9e par un seul conducteur reli\u00e9 directement \u00e0 un piquet de terre.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Consid\u00e9rez trois modes de protection courants :<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Mode de protection<\/th><th>Tension limit\u00e9e<\/th><th>Ce mode utilise-t-il directement le PE ?<\/th><\/tr><\/thead><tbody><tr><td>L\u2013N<\/td><td>Phase par rapport au neutre<\/td><td>Aucune borne PE directe n'est requise pour ce mode individuel<\/td><\/tr><tr><td>L\u2013PE<\/td><td>Phase par rapport \u00e0 la terre de protection<\/td><td>Oui<\/td><\/tr><tr><td>N\u2013PE<\/td><td>Neutre par rapport \u00e0 la terre de protection<\/td><td>Oui<\/td><\/tr><tr><td>DC+\u2013PE \/ DC\u2212\u2013PE<\/td><td>Conducteurs PV par rapport \u00e0 la terre (PE)<\/td><td>Oui<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">C'est la cl\u00e9 pour comprendre la question.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Un \u00e9l\u00e9ment de protection L-N peut toujours \u00e9cr\u00eater la tension diff\u00e9rentielle entre la phase et le neutre, m\u00eame si cet \u00e9l\u00e9ment sp\u00e9cifique n'est pas connect\u00e9 directement \u00e0 la terre (PE). Cependant, si l'installation n\u00e9cessite \u00e9galement une protection contre les surtensions en mode commun par rapport \u00e0 la terre (PE), un chemin L-N seul ne remplace pas les modes de protection requis li\u00e9s \u00e0 la terre ni le syst\u00e8me de liaison \u00e9quipotentielle.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-protection-modes-ln-lpe-npe-1024x576.jpg\" alt=\"SPD L-N L-PE and N-PE surge protection modes\" class=\"wp-image-4591\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-protection-modes-ln-lpe-npe-1024x576.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-protection-modes-ln-lpe-npe-300x169.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-protection-modes-ln-lpe-npe-768x432.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-protection-modes-ln-lpe-npe-1536x864.jpg 1536w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-protection-modes-ln-lpe-npe-18x10.jpg 18w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-protection-modes-ln-lpe-npe-600x338.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-protection-modes-ln-lpe-npe.jpg 1672w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">L-N, L-PE et N-PE sont des modes de protection diff\u00e9rents pour les parafoudres (SPD). Chacun limite la tension entre des conducteurs diff\u00e9rents.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">3. Un parafoudre peut-il fonctionner sans terre (PE) ?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Un parafoudre peut-il fonctionner sans mise \u00e0 la terre ou conducteur de protection (PE) ?<\/strong> Si le parafoudre ne poss\u00e8de qu'un mode de protection entre conducteurs actifs, ce mode peut toujours r\u00e9agir \u00e0 une diff\u00e9rence de tension entre ces conducteurs. Mais un mode de protection d\u00e9pendant de la terre (PE) ne peut pas fonctionner comme pr\u00e9vu si sa connexion \u00e0 la terre est absente.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Cela signifie que deux affirmations peuvent \u00eatre vraies simultan\u00e9ment :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Un parafoudre n'a pas toujours besoin d'une connexion PE pour chaque \u00e9l\u00e9ment de protection interne individuel.<\/li>\n\n\n\n<li>Un dispositif complet de protection contre les surtensions pour les syst\u00e8mes \u00e9lectriques repose souvent sur le PE et la liaison \u00e9quipotentielle pour les chemins de d\u00e9charge importants.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Par cons\u00e9quent, ne jamais supprimer, contourner ou improviser la connexion PE simplement parce qu'un parafoudre affiche un indicateur d'\u00e9tat vert.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">La fen\u00eatre d'\u00e9tat indique normalement l'\u00e9tat d'un m\u00e9canisme interne surveill\u00e9. Elle ne prouve pas que le conducteur PE externe existe, que le syst\u00e8me de liaison est correct ou que la longueur de connexion est acceptable.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Que se passe-t-il si le fil PE est d\u00e9connect\u00e9 ?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Si un parafoudre est con\u00e7u avec des chemins de protection L-PE, N-PE, DC+-PE ou DC--PE et que la connexion PE devient ouverte, ces modes n'ont plus la connexion externe pr\u00e9vue.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Les cons\u00e9quences possibles incluent :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>la perte du chemin de d\u00e9charge en mode commun pr\u00e9vu ;<\/li>\n\n\n\n<li>tension transitoire plus \u00e9lev\u00e9e apparaissant entre l'\u00e9quipement et la terre de protection (PE) ;<\/li>\n\n\n\n<li>coordination incorrecte avec la protection en aval ;<\/li>\n\n\n\n<li>une impression trompeuse que le parafoudre est en bon \u00e9tat car l'indicateur reste normal ;<\/li>\n\n\n\n<li>risque accru si d'autres fonctions de mise \u00e0 la terre de protection sont \u00e9galement compromises.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">L'absence de conducteur de protection n'est pas un raccourci pour le d\u00e9pannage d'un parafoudre. L'installation doit \u00eatre inspect\u00e9e et corrig\u00e9e par une personne qualifi\u00e9e conform\u00e9ment aux instructions de l'\u00e9quipement et aux r\u00e8gles \u00e9lectriques en vigueur.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">4. Un parafoudre peut-il fonctionner sans terre dans les syst\u00e8mes TN, TT et IT ?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">La r\u00e9ponse \u00e0 la question \u201c un parafoudre peut-il fonctionner sans terre ? \u201d varie car l'architecture de mise \u00e0 la terre change dans les syst\u00e8mes TN, TT et IT.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/tn-tt-it-spd-grounding-comparison-1024x576.jpg\" alt=\"\" class=\"wp-image-4592\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/tn-tt-it-spd-grounding-comparison-1024x576.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/tn-tt-it-spd-grounding-comparison-300x169.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/tn-tt-it-spd-grounding-comparison-768x432.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/tn-tt-it-spd-grounding-comparison-1536x864.jpg 1536w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/tn-tt-it-spd-grounding-comparison-18x10.jpg 18w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/tn-tt-it-spd-grounding-comparison-600x338.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/tn-tt-it-spd-grounding-comparison.jpg 1672w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Syst\u00e8mes TN-S et partie TN-S des syst\u00e8mes TN-C-S<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Dans un sch\u00e9ma TN-S, le neutre et le conducteur de protection (PE) sont des conducteurs s\u00e9par\u00e9s dans l'installation. Le parafoudre doit \u00eatre s\u00e9lectionn\u00e9 et raccord\u00e9 en fonction de la configuration du syst\u00e8me et des modes de protection concern\u00e9s.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dans les syst\u00e8mes TN-C-S, le conducteur PEN en amont est divis\u00e9 en conducteurs N et PE distincts en un point d\u00e9fini. Un parafoudre install\u00e9 sur la partie TN-S doit \u00eatre adapt\u00e9 \u00e0 cette partie du syst\u00e8me. Le sch\u00e9ma de raccordement exact doit respecter les instructions du produit et les exigences locales.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Do not create an extra neutral-to-earth link beside the SPD as an improvised \u201cbetter ground.\u201d Neutral\/PE bonding is a system-design issue, not a field modification to improve SPD performance.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">TT Systems<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">In a TT system, the installation\u2019s exposed conductive parts are connected to a local earth electrode while the supply neutral has its own source earthing arrangement.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This affects SPD topology, protection modes, temporary overvoltage behavior, and coordination with protective devices. Depending on the design, manufacturers often provide specific TT-compatible SPD arrangements rather than treating a TN model as universally interchangeable.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The correct question is therefore not \u201cDoes TT have a ground rod?\u201d but:<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\"><strong>Is this SPD and its connection arrangement specifically suitable for the TT system at this installation point?<\/strong><\/p>\n<\/blockquote>\n\n\n\n<h3 class=\"wp-block-heading\">IT Systems<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">In an IT system, the supply may be isolated from earth or connected to earth through an impedance, while exposed conductive parts remain earthed according to the installation design.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This creates different voltage conditions, especially during a first insulation fault. An SPD used in an IT system must therefore be explicitly suitable for that system and for the possible continuous and temporary voltages it can experience.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Do not choose an SPD for an IT system solely because its Uc value appears high enough.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For AC SPDs, IEC 61643-11:2025 specifies performance and safety requirements for SPDs connected to AC low-voltage power systems. System selection and installation still require coordination with the actual network and installation rules. See the <a href=\"https:\/\/webstore.iec.ch\/en\/publication\/65314\" rel=\"noopener\">IEC 61643-11:2025 publication page<\/a>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">5. What About a Floating Solar PV DC System?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In solar PV systems, the question \u201ccan an SPD work without ground?\u201d becomes even more complicated because the DC circuit may be intentionally floating.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Many PV DC circuits operate with neither DC+ nor DC\u2212 intentionally bonded directly to earth during normal operation. This is often described as a floating or unearthed DC array.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">But that does <strong>pas<\/strong> mean the whole PV installation has no protective earth, bonding or surge path to PE.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A PV SPD may provide coordinated protection between:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>DC+ and DC\u2212;<\/li>\n\n\n\n<li>DC+ and PE;<\/li>\n\n\n\n<li>DC\u2212 and PE.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Some PV SPDs use a Y-type internal circuit specifically intended for photovoltaic applications. The correct arrangement depends on the inverter topology, PV earthing arrangement, maximum PV voltage, insulation-monitoring concept and the manufacturer\u2019s approved circuit.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is why a floating PV system can still use a PE-connected SPD arrangement.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">IEC 61643-31 applies to SPDs intended for the DC side of photovoltaic installations up to 1500 V DC and covers their performance characteristics, safety requirements, test methods and ratings. See the <a href=\"https:\/\/webstore.iec.ch\/en\/publication\/26931\" rel=\"noopener\">IEC 61643-31 publication page<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Before selecting a PV SPD, also verify Ucpv, In, Imax, Up and Iscpv. Our <a href=\"https:\/\/cnkuangya.com\/fr\/blog\/dc-spd-specifications\/\">guide des sp\u00e9cifications des parafoudres CC<\/a> explains what these markings mean and why the largest kA number is not enough.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/floating-pv-system-spd-pe-path-1024x576.jpg\" alt=\"Floating solar PV system with SPD connected to PE\" class=\"wp-image-4593\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/floating-pv-system-spd-pe-path-1024x576.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/floating-pv-system-spd-pe-path-300x169.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/floating-pv-system-spd-pe-path-768x432.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/floating-pv-system-spd-pe-path-1536x864.jpg 1536w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/floating-pv-system-spd-pe-path-18x10.jpg 18w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/floating-pv-system-spd-pe-path-600x338.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/floating-pv-system-spd-pe-path.jpg 1672w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">A floating PV DC circuit can still use PE-connected surge protection. \u201cFloating\u201d does not mean the installation has no protective bonding.<\/figcaption><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Does a 2P or 3P PV SPD Tell You the Grounding Method?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Non.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A 2P or 3P description does not automatically tell you:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>which conductor is connected to PE;<\/li>\n\n\n\n<li>whether the internal circuit is a Y configuration;<\/li>\n\n\n\n<li>whether the product is intended for a floating or grounded PV system;<\/li>\n\n\n\n<li>which surge modes are protected.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">For the same reason, AC module count can also be misleading. If you are comparing neutral\/PE arrangements, see our <a href=\"https:\/\/cnkuangya.com\/fr\/blog\/3-1-vs-4-0-spd\/\">Comparaison des parafoudres 3+1 vs 4+0<\/a>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">6. Why a Long Ground or PE Lead Can Reduce SPD Protection<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">An SPD can be correctly selected and correctly connected to PE, yet still provide poorer installed protection because the connection conductors are too long.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The reason is conductor inductance.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">During a fast-rising surge current, additional voltage develops across the SPD connecting conductors:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>\u0394U = L \u00d7 di\/dt<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">O\u00f9 ?<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u0394U<\/strong> = additional voltage developed across the conductor;<\/li>\n\n\n\n<li><strong>L<\/strong> = conductor inductance;<\/li>\n\n\n\n<li><strong>di\/dt<\/strong> = rate of change of surge current.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">This means the equipment does not necessarily see only the SPD\u2019s datasheet voltage protection level Up. The installed voltage can also include voltage developed across the connection path.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Schneider Electric\u2019s Electrical Installation Guide recommends keeping the total SPD connection length to the network and earth terminal block at no more than approximately 50 cm in the illustrated arrangement and explains the added inductive voltage created by longer conductors. See its <a href=\"https:\/\/www.electrical-installation.org\/enwiki\/Connection_of_Surge_Protection_Device\" rel=\"noopener\">SPD connection guidance<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The current consolidated IEC installation standard is IEC 60364-5-53:2019 + Amendment 1:2020 + Amendment 2:2024, which includes Clause 534 for surge protective devices. See the <a href=\"https:\/\/webstore.iec.ch\/en\/publication\/104394\" rel=\"noopener\">IEC 60364-5-53 consolidated publication page<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">If you want a deeper explanation of why conductor length matters during a surge, read our guide on <a href=\"https:\/\/cnkuangya.com\/fr\/blog\/spd-distance-from-inverter\/\">SPD distance from the inverter and connection lead length<\/a>.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-pe-connection-lead-length-1024x576.jpg\" alt=\"SPD PE connection lead length short vs long wiring\" class=\"wp-image-4594\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-pe-connection-lead-length-1024x576.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-pe-connection-lead-length-300x169.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-pe-connection-lead-length-768x432.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-pe-connection-lead-length-1536x864.jpg 1536w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-pe-connection-lead-length-18x10.jpg 18w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-pe-connection-lead-length-600x338.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-pe-connection-lead-length.jpg 1672w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Long SPD connection conductors add inductive voltage during fast-rising surge currents, so short and direct wiring is important.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">So when asking whether an SPD can work without ground, the quality and length of the PE connection are just as important as whether a protective-earth conductor is physically present.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Short Does Not Mean \u201cRun a Separate Wire to a Random Ground Rod\u201d<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Trying to reduce lead length by bypassing the approved panel bonding arrangement and connecting an SPD to a separate, isolated earth electrode can create a different problem: the installation may no longer be equipotentially bonded as required.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The correct objective is not \u201cfind the nearest piece of earth.\u201d<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C'est :<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\"><strong>Connect the SPD to the manufacturer-specified PE\/bonding point using the shortest practical, low-impedance path permitted by the system design.<\/strong><\/p>\n<\/blockquote>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">7. What Happens If an SPD Has Poor Grounding or Bonding?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Poor grounding is not one single failure mode. The effect depends on what is actually wrong.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Probl\u00e8me<\/th><th>Possible Effect<\/th><th>Ce qu'il faut v\u00e9rifier<\/th><\/tr><\/thead><tbody><tr><td>PE conductor missing<\/td><td>PE-dependent protection modes may not function as intended<\/td><td>Wiring diagram, PE continuity, bonding arrangement<\/td><\/tr><tr><td>Loose PE terminal<\/td><td>Unstable\/high-impedance surge path, heating or arcing risk under fault conditions<\/td><td>Terminal condition and specified torque<\/td><\/tr><tr><td>Very long SPD connection<\/td><td>Higher installed residual voltage due to inductive voltage<\/td><td>Lead length and routing<\/td><\/tr><tr><td>Large conductor loop<\/td><td>Higher inductive coupling and loop impedance<\/td><td>Routing and loop area<\/td><\/tr><tr><td>Wrong TN\/TT\/IT SPD topology<\/td><td>Incorrect protection modes or unsuitable voltage stress<\/td><td>System earthing arrangement and manufacturer approval<\/td><\/tr><tr><td>Unbonded conductive systems<\/td><td>Dangerous transient potential differences may remain<\/td><td>Equipotential bonding of incoming services and installation<\/td><\/tr><tr><td>Green SPD indicator but external wiring fault<\/td><td>False confidence<\/td><td>Inspect the complete installation, not only the indicator<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-grounding-mistakes-1024x576.jpg\" alt=\"Common SPD grounding mistakes including missing PE and long wiring\" class=\"wp-image-4595\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-grounding-mistakes-1024x576.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-grounding-mistakes-300x169.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-grounding-mistakes-768x432.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-grounding-mistakes-1536x864.jpg 1536w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-grounding-mistakes-18x10.jpg 18w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-grounding-mistakes-600x338.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-grounding-mistakes.jpg 1672w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">A green SPD status window cannot compensate for missing PE, loose terminals, excessive conductor length, or incorrect bonding.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Does Better Earth Resistance Automatically Mean Better SPD Performance?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Not by itself.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is another important distinction.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A low measured earth-electrode resistance can be useful for the earthing system, but SPD performance during a fast transient also depends heavily on:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>conductor inductance;<\/li>\n\n\n\n<li>connection length;<\/li>\n\n\n\n<li>loop area;<\/li>\n\n\n\n<li>bonding arrangement;<\/li>\n\n\n\n<li>protection mode;<\/li>\n\n\n\n<li>surge waveform;<\/li>\n\n\n\n<li>SPD Up;<\/li>\n\n\n\n<li>equipment impulse withstand voltage.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Therefore, a long conductor to an excellent earth electrode can still develop significant transient voltage during a steep surge current.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For surge protection, think in terms of <strong>impedance and equipotential bonding<\/strong>, not only DC or low-frequency resistance.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Can an SPD Work Without Ground If It Is Connected L\u2013N Only?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Can an SPD work without ground<\/strong> when it only protects L\u2013N? It may limit the voltage between L and N if that is an approved protection mode of the device.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">However, three cautions are essential.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. L\u2013N Protection Is Not the Same as L\u2013PE Protection<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">If a surge raises both L and N relative to PE, an L\u2013N element may see relatively little differential voltage even though the equipment is experiencing a large common-mode voltage relative to earth.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. Equipment Interfaces May Reference PE<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Electronic equipment can have chassis connections, signal cables, communication ports, antennas, shields or other conductive interfaces that create additional surge paths.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3. The Complete SPD Assembly Must Be Used as Designed<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Do not intentionally leave a PE terminal disconnected on an SPD that is designed to use it. The correct wiring diagram is part of the product\u2019s protection concept.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">SPD Grounding vs Backup Fuse: They Solve Different Problems<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A backup fuse or circuit breaker does not replace grounding.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Likewise, grounding does not replace backup overcurrent protection where the SPD manufacturer requires it.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Component \/ Function<\/th><th>Main Role<\/th><\/tr><\/thead><tbody><tr><td>DOCUP<\/td><td>Limits transient overvoltage and diverts surge current through defined protection modes<\/td><\/tr><tr><td>PE \/ bonding system<\/td><td>Provides protective bonding and reference\/discharge paths according to the installation design<\/td><\/tr><tr><td>Backup fuse or circuit breaker<\/td><td>Helps isolate fault current according to the SPD manufacturer\u2019s coordination requirements<\/td><\/tr><tr><td>Earth electrode<\/td><td>Connects the installation earthing system to earth<\/td><\/tr><tr><td>Voltage protection relay \/ regulator<\/td><td>Addresses longer-duration abnormal voltage depending on device type<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">If you are selecting upstream protection, see our practical guide: <a href=\"https:\/\/cnkuangya.com\/fr\/blog\/spd-backup-fuse\/\">does an SPD need a backup fuse or circuit breaker?<\/a><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">How to Check SPD Grounding Before Installation<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Use the following sequence as a design and inspection checklist. It is not a substitute for local electrical rules or the manufacturer\u2019s instructions.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 1 \u2014 Identify the Electrical System<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Confirm whether the circuit is:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>single-phase AC;<\/li>\n\n\n\n<li>three-phase AC;<\/li>\n\n\n\n<li>TN-S \/ TN-C \/ TN-C-S;<\/li>\n\n\n\n<li>TT;<\/li>\n\n\n\n<li>IT;<\/li>\n\n\n\n<li>solar PV DC;<\/li>\n\n\n\n<li>another DC system.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Step 2 \u2014 Identify the SPD Protection Modes<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Read the internal circuit or wiring diagram, not only the product front label.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Look for protection paths such as L\u2013N, L\u2013PE, N\u2013PE, L1\/L2\/L3 relationships, DC+\u2013PE and DC\u2212\u2013PE.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 3 \u2014 Confirm the PE \/ Bonding Point<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Connect only to the approved PE or bonding terminal shown by the manufacturer and installation design.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 4 \u2014 Keep Connections Short and Direct<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Avoid unnecessary conductor loops, coils and wide separation between surge-current paths.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 5 \u2014 Check SPD Voltage Ratings<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">For AC, confirm Uc and the applicable system voltage. For PV, confirm Ucpv against the maximum possible PV voltage, including cold-weather Voc where relevant.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 6 \u2014 Check Up and Equipment Coordination<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Remember that installed protection depends on both the SPD\u2019s Up and the voltage contribution of the connecting conductors.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 7 \u2014 Check Backup Protection<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Verify the manufacturer\u2019s maximum backup fuse \/ circuit-breaker requirements and the prospective short-circuit conditions.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 8 \u2014 Inspect the Complete Protection Architecture<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">If an inverter already contains an SPD, do not assume external surge protection is unnecessary. Cable distance, system architecture and the location of the built-in SPD still matter. See our guide on <a href=\"https:\/\/cnkuangya.com\/fr\/blog\/solar-inverter-built-in-spd\/\">solar inverter built-in SPD and external SPD requirements<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">SPD Grounding Checklist for Buyers and Installers<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Before deciding whether an SPD can work without ground in a real installation, check the complete protection system rather than judging the SPD alone.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>V\u00e9rifier<\/th><th>Question<\/th><th>Pourquoi c'est important<\/th><\/tr><\/thead><tbody><tr><td>Syst\u00e8me<\/td><td>TN, TT, IT, AC or PV DC?<\/td><td>Determines compatible SPD topology<\/td><\/tr><tr><td>Les modes de protection<\/td><td>Which conductor pairs are protected?<\/td><td>Shows what voltage differences the SPD can limit<\/td><\/tr><tr><td>Raccordement PE<\/td><td>Is PE required and correctly connected?<\/td><td>Essential for PE-dependent protection modes<\/td><\/tr><tr><td>Bonding<\/td><td>Are relevant conductive systems equipotentially bonded?<\/td><td>Reduces dangerous transient potential differences<\/td><\/tr><tr><td>Lead length<\/td><td>Are SPD connections as short and direct as practical?<\/td><td>Reduces added inductive voltage<\/td><\/tr><tr><td>Tension<\/td><td>Is Uc \/ Ucpv correct?<\/td><td>Avoids continuous overvoltage stress<\/td><\/tr><tr><td>Protection level<\/td><td>Is Up coordinated with the equipment?<\/td><td>Determines residual voltage stress<\/td><\/tr><tr><td>Surge rating<\/td><td>Are In, Imax and\/or Iimp suitable?<\/td><td>Matches expected surge duty<\/td><\/tr><tr><td>Short-circuit conditions<\/td><td>Are SCCR \/ Iscpv and backup protection suitable?<\/td><td>Important for safe failure and isolation<\/td><\/tr><tr><td>Manufacturer diagram<\/td><td>Does the installed wiring match the approved circuit?<\/td><td>Prevents topology mistakes<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-grounding-installation-checklist-1024x576.jpg\" alt=\"SPD grounding and PE installation checklist\" class=\"wp-image-4596\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-grounding-installation-checklist-1024x576.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-grounding-installation-checklist-300x169.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-grounding-installation-checklist-768x432.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-grounding-installation-checklist-1536x864.jpg 1536w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-grounding-installation-checklist-18x10.jpg 18w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-grounding-installation-checklist-600x338.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-grounding-installation-checklist.jpg 1672w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Check the system type, protection modes, PE and bonding, lead length, voltage ratings, Up, and backup protection before selecting or installing an SPD.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">For photovoltaic projects, KUANGYA provides <a href=\"https:\/\/cnkuangya.com\/fr\/dc-spd\/\">Dispositifs de protection contre les surtensions en courant continu<\/a> for different PV voltage classes and installation requirements. Final model selection should always be based on the actual PV voltage, earthing arrangement, protection mode, SPD type and system fault conditions.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Questions fr\u00e9quemment pos\u00e9es<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Un parafoudre peut-il fonctionner sans mise \u00e0 la terre ?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Sometimes an individual protection mode such as L\u2013N can operate without a direct PE connection. However, that does not mean the complete surge-protection system can ignore PE, earthing or equipotential bonding. Any SPD mode designed to operate between a live conductor and PE requires the intended PE connection.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Does every SPD need a PE wire?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">When people ask \u201ccan an SPD work without ground?\u201d, the answer depends on the SPD circuit rather than on one universal rule. Some devices or protection modes operate only between active conductors, while many power SPDs include PE-related protection modes. Follow the manufacturer\u2019s circuit diagram and select the SPD for the actual TN, TT, IT or DC\/PV system.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Will an SPD still work if the ground wire is too long?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The SPD may still operate, but a long connection can add inductive voltage during a fast-rising surge current. This can increase the voltage that appears at the protected equipment. Short, direct connections are therefore an important part of SPD installation.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Can I connect an SPD directly to a separate ground rod?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Do not improvise an isolated grounding path simply to make the SPD conductor shorter. The SPD should be connected to the approved PE\/bonding point in accordance with the system design, manufacturer instructions and applicable electrical rules.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Does a lower earth resistance always improve SPD protection?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Not by itself. Surge performance also depends on high-frequency impedance, connection length, conductor routing, loop area, bonding and the SPD\u2019s protection characteristics. A low earth-electrode resistance does not compensate for poor SPD wiring.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Can a floating PV system use an SPD?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Yes. A PV DC system may have neither polarity intentionally grounded during normal operation while still using a properly designed SPD arrangement with protection paths to PE. Use a PV SPD approved for that topology and voltage.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Does a green SPD indicator prove the grounding is correct?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">No. A status indicator normally reports the condition of the SPD\u2019s internal monitoring or disconnection mechanism. It does not verify external PE continuity, bonding, conductor length or correct earthing-system selection.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Can an SPD replace grounding?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">No. An SPD and the installation\u2019s protective-earthing\/bonding system perform different functions. A surge protective device should be considered part of a coordinated electrical protection system, not a replacement for protective earthing.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Can grounding protect equipment without an SPD?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Grounding and bonding are fundamental parts of electrical safety and lightning\/surge protection, but they do not perform the same voltage-limiting function as an SPD at equipment terminals. A complete design may require both, depending on the installation.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Which standard applies to SPD grounding and installation?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">There is no single standard that answers every installation question. IEC 61643-11 covers AC low-voltage SPD product requirements, IEC 61643-31 covers PV DC SPD product requirements, and IEC 60364-5-53 includes installation requirements for low-voltage electrical installations, including Clause 534 for SPDs. Project-specific lightning-protection and national wiring requirements may also apply.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Conclusion: Can an SPD Work Without Ground?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Un parafoudre peut-il fonctionner sans mise \u00e0 la terre ?<\/strong> The answer cannot be reduced to a simple yes or no.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">An SPD limits voltage across specific protection modes. A mode between active conductors, such as L\u2013N, may operate without directly using PE. But any protection mode that depends on L\u2013PE, N\u2013PE, DC+\u2013PE or DC\u2212\u2013PE requires the designed PE\/bonding path.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">More importantly, surge protection is a system function.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A correctly selected SPD can still perform poorly if:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>the earthing-system topology is wrong;<\/li>\n\n\n\n<li>PE is missing or loose;<\/li>\n\n\n\n<li>the connection conductors are too long;<\/li>\n\n\n\n<li>bonding is incomplete;<\/li>\n\n\n\n<li>the SPD protection modes do not match the circuit;<\/li>\n\n\n\n<li>Uc or Ucpv is incorrect;<\/li>\n\n\n\n<li>backup protection is not coordinated.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">For that reason, do not ask only:<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\">\u201cDoes this SPD have a ground terminal?\u201d<\/p>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">Ask instead:<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\"><strong>\u201cWhat voltage differences must be limited, what protection modes does this SPD provide, and how is the complete system bonded and earthed?\u201d<\/strong><\/p>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">That question leads to a much safer and more technically correct SPD selection.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Sources Reviewed<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/65314\" rel=\"noopener\">IEC 61643-11:2025 \u2014 AC low-voltage surge protective devices<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/26931\" rel=\"noopener\">IEC 61643-31:2018 \u2014 SPDs for photovoltaic installations<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/104394\" rel=\"noopener\">IEC 60364-5-53:2019 + A1:2020 + A2:2024 \u2014 Selection and erection of electrical equipment<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/www.electrical-installation.org\/enwiki\/Connection_of_Surge_Protection_Device\" rel=\"noopener\">Schneider Electric Electrical Installation Guide \u2014 Connection of Surge Protection Device<\/a><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Technical note: This article is intended for product selection and engineering education. Actual SPD installation must follow the device manufacturer\u2019s wiring instructions, the applicable electrical installation standard, and local code requirements.<\/em><\/p>","protected":false},"excerpt":{"rendered":"<p>Can an SPD work without ground? The technically correct answer is: sometimes a particular protection mode can still operate without a direct PE path, but that does not mean the complete surge-protection system is correctly protected without grounding or bonding. A surge protective device does not simply \u201csend every surge into the soil.\u201d It limits [&hellip;]<\/p>\n","protected":false},"author":7,"featured_media":4589,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35],"tags":[],"class_list":["post-4587","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/cnkuangya.com\/fr\/wp-json\/wp\/v2\/posts\/4587","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cnkuangya.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cnkuangya.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cnkuangya.com\/fr\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/cnkuangya.com\/fr\/wp-json\/wp\/v2\/comments?post=4587"}],"version-history":[{"count":1,"href":"https:\/\/cnkuangya.com\/fr\/wp-json\/wp\/v2\/posts\/4587\/revisions"}],"predecessor-version":[{"id":4597,"href":"https:\/\/cnkuangya.com\/fr\/wp-json\/wp\/v2\/posts\/4587\/revisions\/4597"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cnkuangya.com\/fr\/wp-json\/wp\/v2\/media\/4589"}],"wp:attachment":[{"href":"https:\/\/cnkuangya.com\/fr\/wp-json\/wp\/v2\/media?parent=4587"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cnkuangya.com\/fr\/wp-json\/wp\/v2\/categories?post=4587"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cnkuangya.com\/fr\/wp-json\/wp\/v2\/tags?post=4587"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}