{"id":4474,"date":"2026-09-07T10:43:34","date_gmt":"2026-09-07T02:43:34","guid":{"rendered":"https:\/\/cnkuangya.com\/?p=4474"},"modified":"2026-09-07T16:20:23","modified_gmt":"2026-09-07T08:20:23","slug":"why-spd-connected-in-parallel","status":"publish","type":"post","link":"https:\/\/cnkuangya.com\/de\/blog\/why-spd-connected-in-parallel\/","title":{"rendered":"Warum wird ein \u00dcberspannungsschutzger\u00e4t (SPD) parallel statt in Reihe geschaltet?"},"content":{"rendered":"<p class=\"wp-block-paragraph\">Wenn Sie sich eine typische Installation eines \u00dcberspannungsschutzger\u00e4ts (SPD) ansehen, werden Sie m\u00f6glicherweise einen Unterschied zu einer Sicherung oder einem Leitungsschutzschalter feststellen.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Eine Sicherung oder ein Leitungsschutzschalter wird normalerweise in Reihe mit dem Stromkreis installiert, sodass der Laststrom durch ihn hindurchflie\u00dft.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ein typischer \u00dcberspannungsschutz f\u00fcr die Stromversorgung wird \u00fcblicherweise <strong>parallel<\/strong> zu dem von ihm gesch\u00fctzten Stromkreis angeschlossen, weshalb viele Installateure fragen, warum ein <strong>SPD parallel statt in Reihe geschaltet wird<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Warum?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Die einfache Antwort lautet, dass ein parallel geschalteter \u00dcberspannungsschutz (SPD) nicht den normalen Laststrom f\u00fchren muss. Unter normalen Betriebsbedingungen verbleibt er in einem hochohmigen Zustand. Bei einer transienten \u00dcberspannung beginnt der SPD zu leiten und bietet einen niederohmigen Pfad f\u00fcr den Sto\u00dfstrom, wodurch die Spannung an den gesch\u00fctzten Ger\u00e4ten begrenzt wird.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Deshalb wird die Parallelschaltung h\u00e4ufig f\u00fcr Typ-1- und Typ-2-SPDs in Stromverteilungs- und Photovoltaikanlagen verwendet.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u201cSPD = immer parallel\u201d ist jedoch keine absolute Regel. F\u00fcr bestimmte Anwendungen gibt es auch in Reihe geschaltete SPDs und \u00dcberspannungsfilter. In diesem Artikel sprechen wir haupts\u00e4chlich \u00fcber den \u00fcblichen parallel geschalteten Netz-SPD, der in AC-Verteilungen und Solar-PV-DC-Systemen eingesetzt wird.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Kurze Antwort: Parallel- vs. Reihenschaltung von SPDs<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Eine typische <strong>Parallel geschalteter SPD<\/strong> ist so konzipiert, dass er auf transiente \u00dcberspannungsereignisse reagiert, ohne den normalen Betriebsstrom der Last zu f\u00fchren.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Unter normalen Bedingungen:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Stromquelle \u2192 Last<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Der SPD verbleibt im Standby-Modus.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Bei einem \u00dcberspannungsereignis \u00e4ndert der SPD sein elektrisches Verhalten und leitet den Sto\u00dfstrom \u00fcber seinen Schutzpfad ab, wodurch die an empfindlichen Ger\u00e4ten anliegende Spannung begrenzt wird.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Eine vereinfachte Parallelschaltung sieht wie folgt aus:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Stromquelle \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 Last\n<\/code><\/pre>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-parallel-connection-wiring-1024x683.jpg\" alt=\"SPD parallel connection wiring in an electrical distribution system\" class=\"wp-image-4476\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-parallel-connection-wiring-1024x683.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-parallel-connection-wiring-300x200.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-parallel-connection-wiring-768x512.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-parallel-connection-wiring-18x12.jpg 18w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-parallel-connection-wiring-600x400.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-parallel-connection-wiring.jpg 1536w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Ein typischer parallel geschalteter SPD wird parallel zum gesch\u00fctzten Stromkreis installiert und nicht direkt in den normalen Laststrompfad eingef\u00fcgt.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Der SPD wird parallel zum Stromkreis angeschlossen, anstatt direkt in den normalen Laststrompfad eingef\u00fcgt zu werden. <strong><a href=\"https:\/\/www.phoenixcontact.com\/assets\/c8428ddc-254d-40b8-a2f2-540ac13bd818\/index.html#0\" rel=\"noopener\">Grundlagen des \u00dcberspannungsschutzes von Phoenix Contact<\/a><\/strong> erkl\u00e4rt zudem, dass SPDs parallel zu den zu sch\u00fctzenden Ger\u00e4ten oder zwischen den entsprechenden Leitern installiert werden k\u00f6nnen.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Eaton beschreibt parallel oder als Nebenschluss geschaltete SPDs auf die gleiche Weise: Ihre Anschlussleiter f\u00fchren nicht den normalen Betriebsstrom, sondern leiten den kurzzeitigen Strom, der mit transienten Ereignissen verbunden ist.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dieser grundlegende Unterschied erkl\u00e4rt, warum die meisten g\u00e4ngigen \u00dcberspannungsschutzger\u00e4te (SPD) parallel geschaltet werden.<\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-9-16 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"Why is an SPD connected in parallel instead of series?\" width=\"563\" height=\"1000\" src=\"https:\/\/www.youtube.com\/embed\/itkgmV2pQ98?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><figcaption class=\"wp-element-caption\">Sehen Sie, wie sich ein typischer SPD im Normalbetrieb und bei einem \u00dcberspannungsereignis verh\u00e4lt.<\/figcaption><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Was passiert mit einem SPD w\u00e4hrend des Normalbetriebs?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Um die Parallelschaltung zu verstehen, ist es hilfreich, zun\u00e4chst zu wissen, was das SPD tut, wenn keine \u00dcberspannung vorliegt.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Unter normaler Systemspannung<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">W\u00e4hrend des Normalbetriebs bleibt die Systemspannung unter dem Wert, bei dem das SPD nennenswert leitet.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Bei einem SPD auf MOV-Basis weist das Schutzelement unter normalen Spannungsbedingungen eine relativ hohe Impedanz auf.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dies bedeutet, dass der Hauptbetriebsstrom weiterhin \u00fcber den normalen Stromkreis zur Last flie\u00dft.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Das SPD befindet sich im Wesentlichen im Standby-Modus.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Eine vereinfachte Darstellung ist:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Versorgung \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 Last\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Dies bedeutet nicht zwangsl\u00e4ufig, dass absolut kein Strom durch jeden SPD flie\u00dft. Abh\u00e4ngig von der SPD-Technologie und -Bauweise kann ein geringer Leck- oder Betriebsstrom vorhanden sein.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Der wichtige Punkt ist:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Der normale Laststrom muss nicht durch einen typischen parallel geschalteten SPD flie\u00dfen.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Think of the SPD as a protection path waiting beside the main circuit rather than a component that must continuously carry the equipment&#8217;s operating current.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Was passiert, wenn ein \u00dcberspannungsereignis auftritt?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Eine \u00dcberspannung ist ein kurzzeitiger Spannungsanstieg, der durch Ereignisse wie blitzbedingte Transienten oder Schaltvorg\u00e4nge verursacht werden kann.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">When the voltage across the SPD rises sufficiently, the SPD&#8217;s protection elements begin conducting.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Wenn Sie eine detailliertere Erkl\u00e4rung dazu w\u00fcnschen, wie die Schutzelemente auf transiente \u00dcberspannungen reagieren, lesen Sie unseren Leitfaden unter <strong><a href=\"https:\/\/cnkuangya.com\/de\/blog\/how-dc-spd-works-operating-principles-components-engineers-guide\/\">die Funktionsweise eines DC-SPD<\/a><\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Seine Impedanz sinkt im Vergleich zum Normalzustand stark ab.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dies erm\u00f6glicht es dem Sto\u00dfstrom, durch den verf\u00fcgbaren Schutzpfad zu flie\u00dfen, und begrenzt die transiente Spannung, die an den gesch\u00fctzten Ger\u00e4ten auftritt.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Eine vereinfachte Darstellung ist:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>                 Ger\u00e4t\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Dieses Diagramm ist jedoch nur ein vereinfachtes Beispiel.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ein SPD f\u00fchrt <strong>leiten nicht immer jeden \u00dcberspannungsimpuls direkt zur Erde ab<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Abh\u00e4ngig vom elektrischen System und der Ausf\u00fchrung des SPD k\u00f6nnen Schutzmodi zwischen folgenden Punkten bestehen:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Au\u00dfenleiter und Neutralleiter<\/li>\n\n\n\n<li>Au\u00dfenleiter und Schutzleiter<\/li>\n\n\n\n<li>Neutralleiter und Schutzleiter<\/li>\n\n\n\n<li>Au\u00dfenleiter und Au\u00dfenleiter<\/li>\n\n\n\n<li>DC-Plus und DC-Minus<\/li>\n\n\n\n<li>DC-Leiter und Schutzleiter<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Aus diesem Grund ist es pr\u00e4ziser zu sagen:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Der \u00dcberspannungsschutz (SPD) bietet einen kontrollierten Pfad f\u00fcr Sto\u00dfstr\u00f6me und begrenzt die transiente Spannung \u00fcber den zu sch\u00fctzenden Ger\u00e4ten.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Der genaue Strompfad h\u00e4ngt von der SPD-Konfiguration und der Systemtopologie ab.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Warum wird ein SPD parallel geschaltet?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Um zu verstehen, warum ein SPD parallel geschaltet wird, ist es hilfreich zu betrachten, was sowohl w\u00e4hrend des Normalbetriebs als auch bei einem \u00dcberspannungsereignis geschieht.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Es gibt mehrere wichtige Gr\u00fcnde, warum ein <strong>Parallel geschalteter SPD<\/strong> in Stromverteilungssystemen weit verbreitet ist.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. Das SPD muss keinen normalen Laststrom f\u00fchren<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Dies ist einer der gr\u00f6\u00dften Unterschiede zwischen einem SPD und Ger\u00e4ten wie einem Leitungsschutzschalter oder einer Sicherung.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Stellen Sie sich vor, ein Wechselrichter arbeitet normalerweise mit mehreren zehn Ampere.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Bei einem typischen parallel geschalteten SPD muss dieser Betriebsstrom nicht kontinuierlich durch den SPD flie\u00dfen.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Stattdessen:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Quelle \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 Last\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Der SPD ist parallel zum gesch\u00fctzten Stromkreis geschaltet.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dies bedeutet, dass der SPD prim\u00e4r nach den Anforderungen des \u00dcberspannungsschutzes ausgew\u00e4hlt werden kann und nicht nach dem vollen Betriebsstrom jeder nachgeschalteten Last.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Phoenix Contact similarly notes that its parallel-installed power SPDs appear electrically as a branch connected across the power distribution system rather than carrying the circuit&#8217;s normal ampacity.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">2. Der SPD reagiert haupts\u00e4chlich auf \u00dcberspannungsereignisse<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Ein typischer SPD ist spannungsempfindlich.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Bei normaler Systemspannung bleibt er weitgehend inaktiv.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Wenn eine transiente Spannung \u00fcber ihren normalen Betriebsbereich ansteigt, beginnen die Schutzelemente zu leiten.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dies unterscheidet sich grundlegend von einer Sicherung, einem Leitungsschutzschalter oder einem Trennschalter.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Zum Beispiel:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Sicherung<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Quelle \u2192 Sicherung \u2192 Last\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Leitungsschutzschalter<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Quelle \u2192 Schutzschalter \u2192 Last\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Typischer paralleler \u00dcberspannungsschutz (SPD)<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Quelle \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 Last\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Eine Sicherung oder ein Schutzschalter muss normalerweise den Laststrom f\u00fchren, da er sich physisch im Lastpfad befindet.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ein paralleler SPD tut dies nicht.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">3. Die Parallelschaltung bietet einen Pfad f\u00fcr den Sto\u00dfstrom.<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Der Zweck eines SPD besteht nicht darin, jeden Sto\u00dfstrom zu \u201cblockieren\u201d, bevor er die Last erreicht.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Stattdessen reagiert ein spannungsbegrenzender SPD auf die ansteigende transiente Spannung und leitet den Sto\u00dfstrom ab.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dieser Vorgang begrenzt die Spannung \u00fcber dem gesch\u00fctzten Stromkreis.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Zum Beispiel in einer vereinfachten PV-Anlage:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>PV-Generator \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 Wechselrichter\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">W\u00e4hrend des Normalbetriebs flie\u00dft die PV-Leistung weiter in Richtung Wechselrichter.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">W\u00e4hrend eines \u00dcberspannungsereignisses leitet der SPD gem\u00e4\u00df seinem Schutzmodus und tr\u00e4gt dazu bei, die transiente Spannung auf einem niedrigeren Niveau zu halten, als sie andernfalls erreichen w\u00fcrde.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dies ist der grundlegende Grund, warum der SPD parallel zum Stromkreis geschaltet wird.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">4. Der SPD ist normalerweise kein Teil des Hauptstrompfads<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Da der typische SPD als paralleler Zweig angeschlossen ist, bildet er keinen normalen leitenden Pfad zwischen der Quelle und der Last.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dies hat einen wichtigen praktischen Vorteil.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The system&#8217;s normal operating current does not depend on continuously passing through the SPD protection elements.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Nat\u00fcrlich bedeutet dies nicht, dass ein SPD nach der Installation ignoriert werden kann.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">SPDs k\u00f6nnen nach einer anormalen elektrischen Belastung degradieren oder sich trennen, daher sollte ihr Status regelm\u00e4\u00dfig \u00fcberpr\u00fcft werden.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Why Isn&#8217;t a Typical SPD Connected in Series?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Das Verst\u00e4ndnis daf\u00fcr, warum ein SPD parallel geschaltet wird, erkl\u00e4rt auch, warum ein typischer, als Nebenschluss geschalteter SPD nicht in Reihe zum normalen Lastpfad platziert wird.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Leitungsschutzschalter und Sicherungen werden normalerweise in Reihe geschaltet, da sie den Betriebsstrom f\u00fchren m\u00fcssen. Ein typischer paralleler SPD ist f\u00fcr eine andere Funktion ausgelegt.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Der normale Laststrom m\u00fcsste durch ein in Reihe geschaltetes Ger\u00e4t flie\u00dfen.<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Eine echte Reihenschaltung sieht wie folgt aus:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Quelle \u2192 Ger\u00e4t \u2192 Last\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">W\u00fcrde die gesamte SPD-Baugruppe in den Lastpfad eingef\u00fcgt, m\u00fcsste der SPD den kontinuierlichen Laststrom aufnehmen k\u00f6nnen.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Seine Leiter, Anschl\u00fcsse, thermische Auslegung, Kurzschlussfestigkeit und sein Ausfallverhalten m\u00fcssten alle f\u00fcr diese Anwendung ausgelegt sein.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So wird ein \u00fcblicher DIN-Schienen-SPD vom Typ 1 oder Typ 2 normalerweise nicht verwendet.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">SPD-Ableitverm\u00f6gen sind keine Laststromnennwerte<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Dies ist ein besonders wichtiger Punkt beim Lesen eines SPD-Typenschilds.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Angenommen, ein SPD ist wie folgt gekennzeichnet:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>In = 20 kA<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">und<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Imax = 40 kA<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-in-imax-vs-load-current-1024x683.jpg\" alt=\"SPD In and Imax surge current ratings compared with normal load current\" class=\"wp-image-4478\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-in-imax-vs-load-current-1024x683.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-in-imax-vs-load-current-300x200.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-in-imax-vs-load-current-768x512.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-in-imax-vs-load-current-18x12.jpg 18w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-in-imax-vs-load-current-600x400.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-in-imax-vs-load-current.jpg 1536w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">In und Imax beschreiben die Sto\u00dfstromableitf\u00e4higkeit, nicht den normalen Betriebsstrom des gesch\u00fctzten Stromkreises.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Falls diese SPD-Nennwerte weiterhin verwirrend sind, hilft unser <strong><a href=\"https:\/\/cnkuangya.com\/de\/blog\/dc-spd-specifications\/\">Leitfaden f\u00fcr DC-SPD-Spezifikationen<\/a><\/strong> erl\u00e4utert Ucpv, In, Imax, Up und Iscpv im Detail.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Diese Zahlen bedeuten <strong>nicht<\/strong> nicht, dass der SPD daf\u00fcr ausgelegt ist, dauerhaft einen normalen Laststrom von 20 kA oder 40 kA zu f\u00fchren.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Bei Typ-2-Ableitern, <strong>Unter<\/strong> bezieht sich auf den Nennableitsto\u00dfstrom, der mit einem 8\/20 \u03bcs-Stromimpuls assoziiert ist, w\u00e4hrend <strong>Imax<\/strong> sich auf den maximalen Ableitsto\u00dfstrom bezieht, der mit einem 8\/20 \u03bcs-Impuls assoziiert ist.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Phoenix Contact&#8217;s technical definitions likewise describe In and Imax as impulse-current values flowing through the SPD, not normal continuous load-current ratings.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Also:<\/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>In und Imax sind Bemessungswerte f\u00fcr den Ableitsto\u00dfstrom. Sie entsprechen nicht dem normalen Betriebsstrom der Last.<\/strong><\/p>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">Diese Unterscheidung ist bei der Auswahl oder Erl\u00e4uterung eines SPD sehr wichtig.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Bedeutet dies, dass es keine in Reihe geschalteten SPDs gibt?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Nein.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dies ist eine wichtige Ausnahme.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Obwohl die in diesem Artikel behandelten g\u00e4ngigen Typ-1- und Typ-2-\u00dcberspannungsschutzger\u00e4te f\u00fcr die Stromversorgung im Allgemeinen parallel installiert werden, gibt es auch in Reihe geschaltete SPD-Baugruppen und in Reihe geschaltete \u00dcberspannungsfilter.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Schneider Electric weist darauf hin, dass in Reihe geschaltete Produkte \u00fcblicherweise direkt vor bestimmten Lasten installiert werden, w\u00e4hrend parallel geschaltete SPDs die gebr\u00e4uchlichere Anordnung in Schaltanlagen und Verteilern sind.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A series-connected product has to be designed specifically to carry the circuit&#8217;s load current.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Daher w\u00e4re es falsch zu sagen:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>\u201cEin SPD kann niemals in Reihe geschaltet werden.\u201d<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Eine technisch pr\u00e4zisere Aussage lautet:<\/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>Die g\u00e4ngigsten Typ-1- und Typ-2-\u00dcberspannungsschutzger\u00e4te (SPD) f\u00fcr die Energieverteilung werden parallel geschaltet, w\u00e4hrend f\u00fcr spezielle Anwendungen auch eigens entwickelte, in Reihe geschaltete \u00dcberspannungsschutzprodukte existieren.<\/strong><\/p>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">For solar PV and general distribution-board applications, always follow the actual SPD manufacturer&#8217;s wiring diagram.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Parallel- vs. Reihenschaltung: Ein einfacher Vergleich<\/h2>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\">Die folgende Tabelle zeigt, wie ein typisches <strong>Parallel geschalteter SPD<\/strong> sich von einem Ger\u00e4t unterscheidet, das direkt im normalen Laststrompfad installiert ist.<\/p>\n<\/blockquote>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/parallel-spd-vs-series-device-1024x683.jpg\" alt=\"Parallel SPD connection compared with a series-connected electrical device\" class=\"wp-image-4479\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/parallel-spd-vs-series-device-1024x683.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/parallel-spd-vs-series-device-300x200.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/parallel-spd-vs-series-device-768x512.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/parallel-spd-vs-series-device-18x12.jpg 18w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/parallel-spd-vs-series-device-600x400.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/parallel-spd-vs-series-device.jpg 1536w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Ein typisches Parallel-SPD wird \u00fcber den zu sch\u00fctzenden Stromkreis geschaltet, w\u00e4hrend ein in Reihe geschaltetes Ger\u00e4t direkt im normalen Strompfad liegt.<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Merkmal<\/th><th>Typisches Parallel-SPD<\/th><th>In Reihe geschaltetes Ger\u00e4t<\/th><\/tr><\/thead><tbody><tr><td>Direkt im normalen Lastpfad angeschlossen<\/td><td>Nein<\/td><td>Ja<\/td><\/tr><tr><td>Der normale Laststrom flie\u00dft durch das gesamte Ger\u00e4t<\/td><td>Nein<\/td><td>Ja<\/td><\/tr><tr><td>\u00dcbliche Anordnung f\u00fcr Typ 1 \/ Typ 2 \u00dcberspannungsschutzger\u00e4te (SPD)<\/td><td>Ja<\/td><td>Weniger gebr\u00e4uchlich<\/td><\/tr><tr><td>Hauptzweck<\/td><td>Begrenzung transienter \u00dcberspannungen durch Bereitstellung eines Ableitpfades f\u00fcr Sto\u00dfstr\u00f6me<\/td><td>Abh\u00e4ngig von der Produktkonstruktion<\/td><\/tr><tr><td>Dauerstrombelastbarkeit ist entscheidend f\u00fcr das gesamte Ger\u00e4t<\/td><td>Normalerweise nicht auf die gleiche Weise wie ein Reiheneinbauger\u00e4t<\/td><td>Ja<\/td><\/tr><tr><td>Die L\u00e4nge der Anschlussleitungen beeinflusst den Schutz<\/td><td>Ja<\/td><td>Die interne Anordnung kann die Auswirkungen der externen parallelen Leitungsl\u00e4nge reduzieren.<\/td><\/tr><tr><td>Typische Anwendungen<\/td><td>Verteiler, Ger\u00e4teeing\u00e4nge, PV-Anlagen<\/td><td>Ausgew\u00e4hlte empfindliche Lasten oder spezielle Schutz-\/Filteranwendungen<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Der wichtige Punkt ist nicht, dass eine Methode universell \u201cgut\u201d und die andere \u201cschlecht\u201d ist.\u201d<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Es handelt sich um unterschiedliche Produktarchitekturen.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Bei einem normalen DIN-Schienen-Netz-SPD ist die Parallelschaltung jedoch \u00fcblicherweise die vorgesehene Installationsmethode.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Wie wird ein SPD in einem Solar-PV-Gleichstromsystem angeschlossen?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The same principle applies in many photovoltaic systems, where the SPD is connected in parallel with the DC circuit according to the manufacturer&#8217;s wiring configuration.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/dc-spd-parallel-connection-solar-pv-system-1024x683.jpg\" alt=\"DC SPD connected in parallel in a solar PV system\" class=\"wp-image-4477\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/dc-spd-parallel-connection-solar-pv-system-1024x683.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/dc-spd-parallel-connection-solar-pv-system-300x200.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/dc-spd-parallel-connection-solar-pv-system-768x512.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/dc-spd-parallel-connection-solar-pv-system-18x12.jpg 18w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/dc-spd-parallel-connection-solar-pv-system-600x400.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/dc-spd-parallel-connection-solar-pv-system.jpg 1536w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Ein DC-\u00dcberspannungsschutzger\u00e4t (SPD) wird gem\u00e4\u00df der SPD-Konfiguration und dem Schaltplan des Herstellers typischerweise parallel zum PV-Stromkreis geschaltet.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Die Verdrahtung von DC-SPDs erfordert jedoch besondere Sorgfalt.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Es ist nicht korrekt anzunehmen, dass jedes PV-SPD einfach wie folgt verdrahtet wird:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>DC+ \u2192 SPD \u2192 PE\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Die tats\u00e4chliche interne Schutzschaltung kann abweichen.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Abh\u00e4ngig vom Produkt und der Konfiguration der PV-Anlage kann das SPD Schutzmodi bieten zwischen:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>DC+ und PE<\/li>\n\n\n\n<li>DC\u2212 und PE<\/li>\n\n\n\n<li>DC+ und DC\u2212<\/li>\n\n\n\n<li>Eine Kombination dieser Pfade<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">F\u00fcr unterschiedliche Erdungssysteme und PV-Architekturen werden verschiedene SPD-Schaltungsanordnungen verwendet.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Bei einem parallel geschalteten PV-SPD h\u00e4ngt die genaue Anschlussbelegung weiterhin vom SPD-Design, der Systemtopologie und dem Schaltplan des Herstellers ab.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is why the wiring diagram printed on the SPD or provided in the manufacturer&#8217;s installation instructions is so important.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">F\u00fcr photovoltaische DC-Anwendungen ist die spezifische IEC-Produktnorm die IEC 61643-31. DEHN f\u00fchrt zudem die IEC 60364-7-712 und die IEC 60364-5-53 als relevante Installationsnormen f\u00fcr PV- und Niederspannungs-SPD-Anwendungen auf.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u00dcbertragen Sie keinen Schaltplan eines AC-SPD auf ein DC-SPD<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Obwohl AC- und DC-SPDs auf \u00e4hnlichen \u00dcberspannungsschutzprinzipien basieren, sind die Systeme nicht austauschbar.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Gleichstromsysteme stellen zus\u00e4tzliche Herausforderungen dar, da Gleichstrom keinen nat\u00fcrlichen Nulldurchgang aufweist, was die Unterbrechung von Lichtb\u00f6gen bei Gleichstrom erschwert.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Aus diesem Grund muss der SPD speziell f\u00fcr die Gleichspannung, die Systemkonfiguration und die Anwendung geeignet sein.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u00dcberpr\u00fcfen Sie immer:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Maximale Dauerspannung<\/li>\n\n\n\n<li>DC-Polarit\u00e4t und Anschlusskennzeichnungen<\/li>\n\n\n\n<li>SPD-Typ<\/li>\n\n\n\n<li>Schutzmodi<\/li>\n\n\n\n<li>Erdungskonzept<\/li>\n\n\n\n<li>Kurzschlussanforderungen<\/li>\n\n\n\n<li>Schaltplan des Herstellers<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Vor der Installation.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Beispiel: Lesen eines KUANGYA Typ 2 DC-\u00dcberspannungsschutzger\u00e4ts (SPD)<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Am Beispiel eines KUANGYA KYPV\/1000 Typ 2 DC-SPD kann das Typenschild unter anderem folgende Parameter enthalten:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Uc = 1000 V DC<\/strong><\/li>\n\n\n\n<li><strong>In = 20 kA<\/strong><\/li>\n\n\n\n<li><strong>Imax = 40 kA<\/strong><\/li>\n\n\n\n<li><strong>Up = 3,5 kV<\/strong><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">These values describe different parts of the SPD&#8217;s electrical performance.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Uc<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Uc ist die f\u00fcr das SPD spezifizierte maximale Dauerspannung.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Bei der Auswahl einer geeigneten Spannungsbemessung m\u00fcssen die Systemspannung und m\u00f6gliche Betriebsbedingungen ber\u00fccksichtigt werden.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Unter<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">In ist der Nennableitsto\u00dfstrom.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Bei einem Typ-2-\u00dcberspannungsschutzger\u00e4t (SPD) ist dieser mit einer 8\/20 \u03bcs-Sto\u00dfstromwellenform assoziiert.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Imax<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Imax ist der f\u00fcr das SPD spezifizierte maximale Ableitsto\u00dfstrom, der bei diesem Ger\u00e4tetyp ebenfalls mit der 8\/20 \u03bcs-Wellenform assoziiert ist.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Imax ist gleich oder gr\u00f6\u00dfer als In.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Nach oben<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Up ist der Schutzpegel.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Er gibt das Spannungsbegrenzungsverm\u00f6gen des SPD unter spezifizierten Pr\u00fcfbedingungen an.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The key point for today&#8217;s topic is this:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>20 kA In und 40 kA Imax bedeuten nicht, dass w\u00e4hrend des Normalbetriebs kontinuierlich 20 kA oder 40 kA durch das SPD flie\u00dfen.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Dies sind transiente Sto\u00dfstromparameter.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">That is another reason why comparing an SPD&#8217;s In or Imax directly with the load current of an inverter is incorrect.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Does Parallel Connection Mean Wire Length Does Not Matter?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Nein.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In fact, connection length is extremely important for a parallel-connected SPD.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A surge has a very fast current rise.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The connecting conductors therefore have inductance, and the rapidly changing surge current can create an additional voltage drop along those conductors.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">That additional voltage is effectively added to the voltage experienced by the protected equipment.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Nach Angaben von <strong><a href=\"https:\/\/www.nemasurge.org\/correct-installation-of-hard-wired-surge-protective-device\/\" rel=\"noopener\">NEMA\u2019s guidance on hard-wired SPD installation<\/a><\/strong>, the size and length of the connecting leads can affect the performance of a parallel-connected SPD, and short, direct connections are preferred.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Phoenix Contact makes the same point: long connecting conductors can increase the effective voltage protection level seen in the installation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So even if two installations use exactly the same SPD, their real-world protection performance may not be identical if one has much longer connection conductors.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-connection-lead-length-protection-1024x768.jpg\" alt=\"Short and long SPD connection leads compared for surge protection\" class=\"wp-image-4480\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-connection-lead-length-protection-1024x768.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-connection-lead-length-protection-300x225.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-connection-lead-length-protection-768x576.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-connection-lead-length-protection-16x12.jpg 16w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-connection-lead-length-protection-600x450.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-connection-lead-length-protection.jpg 1448w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Short and direct SPD connections generally reduce additional inductive voltage during fast surge-current events.<\/figcaption><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Good Practice<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The SPD connection should generally be:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>As short as practical<\/li>\n\n\n\n<li>As direct as practical<\/li>\n\n\n\n<li>Free from unnecessary loops<\/li>\n\n\n\n<li>Free from unnecessary sharp routing<\/li>\n\n\n\n<li>Installed according to the manufacturer&#8217;s instructions<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">This is also why SPD location matters.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">If you want to understand this issue in more detail, see our guide:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong><a href=\"https:\/\/cnkuangya.com\/de\/blog\/spd-distance-from-inverter\/\">Spielt der Abstand zwischen dem SPD und dem Wechselrichter eine Rolle?<\/a><\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Where Should an SPD Be Installed?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The exact position depends on the system being protected.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For example, an SPD may be installed:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>At a main distribution board<\/li>\n\n\n\n<li>At a sub-distribution board<\/li>\n\n\n\n<li>Near sensitive equipment<\/li>\n\n\n\n<li>At the DC input of a PV inverter<\/li>\n\n\n\n<li>Inside or near a PV combiner box<\/li>\n\n\n\n<li>On the AC side of an inverter<\/li>\n\n\n\n<li>At appropriate lightning protection zone boundaries<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">If your inverter already includes surge protection, do not assume that an additional external SPD is automatically unnecessary. See <strong><a href=\"https:\/\/cnkuangya.com\/de\/blog\/solar-inverter-built-in-spd\/\">Solar-Wechselrichter verf\u00fcgt \u00fcber einen integrierten DC-\u00dcberspannungsschutz (SPD): Ist ein externer \u00dcberspannungsschutz dennoch erforderlich?<\/a><\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The objective is not simply to put \u201cone SPD somewhere in the system.\u201d<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The SPD should be positioned as part of a coordinated protection concept.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For PV systems in particular, cable length and the location of the inverter, modules and building entry points can affect whether additional SPDs are appropriate.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Nach Angaben von <strong><a href=\"https:\/\/www.dehn-international.com\/en\/solutions\/photovoltaics\/buildings\" rel=\"noopener\">DEHN\u2019s photovoltaic surge protection guidance<\/a><\/strong>, SPDs should be installed as close as possible to the equipment being protected, such as the inverter, on both the AC and DC sides.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The specific requirements should always be determined from the applicable installation standard, risk assessment and manufacturer instructions.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Does a Parallel-Connected SPD Need a Fuse or Circuit Breaker?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Sometimes yes, but not always in exactly the same way.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is another area where oversimplified advice can cause problems.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A parallel SPD may require an external:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Sicherung<\/li>\n\n\n\n<li>Leitungsschutzschalter<\/li>\n\n\n\n<li>Backup overcurrent protective device<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">depending on the SPD design and installation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Other SPDs may include internal protective or disconnecting components.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The correct arrangement depends on factors such as:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Manufacturer requirements<\/li>\n\n\n\n<li>SPD design<\/li>\n\n\n\n<li>Maximum permitted backup fuse<\/li>\n\n\n\n<li>Available prospective short-circuit current<\/li>\n\n\n\n<li>Systemspannung<\/li>\n\n\n\n<li>Installationsort<\/li>\n\n\n\n<li>Applicable electrical standard<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-backup-fuse-circuit-breaker-1024x683.jpg\" alt=\"SPD backup fuse and circuit breaker selection factors\" class=\"wp-image-4481\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-backup-fuse-circuit-breaker-1024x683.jpg 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-backup-fuse-circuit-breaker-300x200.jpg 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-backup-fuse-circuit-breaker-768x512.jpg 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-backup-fuse-circuit-breaker-18x12.jpg 18w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-backup-fuse-circuit-breaker-600x400.jpg 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/spd-backup-fuse-circuit-breaker.jpg 1536w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Backup protection requirements depend on the SPD design, system fault current and manufacturer instructions.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">NEMA specifically advises installers to follow the manufacturer&#8217;s requirements regarding fuses, breakers and connection leads.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Therefore, do not assume:<\/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\">\u201cEvery SPD needs exactly the same backup breaker.\u201d<\/p>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">And do not assume:<\/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\">\u201cBecause the SPD is connected in parallel, no overcurrent protection is ever required.\u201d<\/p>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">Both statements can be wrong.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Always check the SPD datasheet and installation instructions.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Why Short SPD Connections Matter So Much<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Imagine two identical SPDs.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Installation A<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The SPD is mounted very close to the protected equipment, with short and direct conductors.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Installation B<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The SPD is several meters away and connected through long conductors.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Although the SPD nameplate is identical, the effective protection at the equipment can be different.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This happens because the connecting conductors contribute additional inductive voltage during a fast surge.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">NEMA explains this relationship using:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>V = L \u00d7 di\/dt<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>V<\/strong> = inductive voltage<\/li>\n\n\n\n<li><strong>L<\/strong> = Leiterinduktivit\u00e4t<\/li>\n\n\n\n<li><strong>di\/dt<\/strong> = rate of change of current<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The faster the current changes and the more inductance there is in the connection, the greater the additional voltage can become.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">You do not need to calculate this formula for every normal installation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Die praktische Lehre ist viel einfacher:<\/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>Keep SPD connections short and direct.<\/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\">Common SPD Wiring Mistakes<\/h2>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-wiring-mistakes-1024x768.png\" alt=\"Common SPD wiring mistakes in surge protection installations\" class=\"wp-image-4482\" srcset=\"https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-wiring-mistakes-1024x768.png 1024w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-wiring-mistakes-300x225.png 300w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-wiring-mistakes-768x576.png 768w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-wiring-mistakes-16x12.png 16w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-wiring-mistakes-600x450.png 600w, https:\/\/cnkuangya.com\/wp-content\/uploads\/2026\/09\/common-spd-wiring-mistakes.png 1448w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Common SPD installation mistakes include long connection leads, incorrect voltage selection and ignoring manufacturer wiring requirements.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Understanding why the SPD is connected in parallel also makes several common installation mistakes easier to recognize.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. Treating a Standard SPD Like a Series Device<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Do not simply place a normal parallel DIN-rail SPD in the main load path unless the manufacturer&#8217;s design specifically requires that configuration.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Follow the wiring diagram for the exact product.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">2. Using Excessively Long Connection Wires<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">A good SPD with poor wiring may provide worse protection than expected.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Long leads increase inductive voltage during a surge.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Short and direct routing is generally preferred.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">3. Ignoring the Protection and Earthing Arrangement<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Do not assume every surge simply flows from one line terminal to earth.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The protection modes depend on the electrical network and SPD design.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Correct PE, bonding and circuit connections are essential where required by the product and installation design.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">4. Choosing the Wrong DC Voltage Rating<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">An SPD must be suitable for the voltage that can continuously appear at its terminals.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is particularly important in PV systems, where string open-circuit voltage changes with temperature.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Choosing an SPD only because it says \u201cDC SPD\u201d is not enough.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The voltage rating must match the actual PV system design.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For a step-by-step method, see our <strong><a href=\"https:\/\/cnkuangya.com\/de\/blog\/dc-spd-selection-guide\/\">DC SPD voltage selection guide for solar PV systems<\/a><\/strong>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">5. Confusing In and Imax With Load Current<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">This is one of the most common misunderstandings.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">An SPD marked:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>In = 20 kA<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">does not mean:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Normal load current = 20 kA<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In and Imax describe surge-current performance under specified impulse conditions.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">They are not normal operating-current ratings.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">6. Ignoring the Manufacturer&#8217;s Backup Protection Requirements<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Do not guess the fuse or breaker size.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Different SPD designs can have different backup protection requirements.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Some products also include integrated protective components.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Check the actual product documentation.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">7. Installing an SPD but Never Checking It Again<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Many modular SPDs include a visual status indicator.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">If the indicator shows a fault or replacement condition, the protection module may need to be replaced.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Some SPDs also have remote signaling contacts for connection to alarms, PLCs or monitoring systems.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Installing the SPD is only the first step.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Its condition should also be checked during maintenance.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For common warning signs and replacement indicators, see <strong><a href=\"https:\/\/cnkuangya.com\/de\/blog\/how-to-know-if-an-spd-is-bad\/\">How to Know If an SPD Is Bad?<\/a><\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Parallel SPD vs. Circuit Breaker: What Is the Difference?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A circuit breaker and an SPD protect against different electrical problems.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Stromkreisunterbrecher<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">A circuit breaker is mainly intended to interrupt abnormal current conditions such as overloads or short circuits.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Because it must sense and interrupt circuit current, it is connected in series with the load.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">SPD<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">An SPD is intended to limit transient overvoltage.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A typical power SPD is connected in parallel so that it can conduct surge current when the transient voltage rises.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">That means:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Circuit breaker \u2192 current protection<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>SPD \u2192 transient overvoltage protection<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">One cannot normally replace the other.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">They perform different jobs.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Parallel SPD vs. Fuse: What Is the Difference?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The same principle applies to a fuse.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A fuse is installed in series with the circuit it protects.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Normal load current passes through the fuse element.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">If excessive current persists, the fuse element opens the circuit.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A typical SPD behaves differently.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">It remains connected across the protected circuit and responds mainly when the voltage reaches a level that causes its protective elements to conduct.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So although fuses, breakers and SPDs may all appear in the same electrical panel, their functions and connection methods are not the same.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">H\u00e4ufig gestellte Fragen<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Is an SPD Connected in Series or Parallel?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Most common Type 1 and Type 2 power SPDs used in distribution boards and similar applications are connected in parallel with the circuit they protect.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">However, specially designed series-connected SPDs and surge filters also exist.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Always follow the wiring instructions for the exact product.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Why Are Type 1 and Type 2 SPDs Usually Connected in Parallel?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">A typical SPD is connected in parallel because it does not need to carry the normal load current.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">During normal voltage conditions, it remains in a high-impedance state.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">When a transient overvoltage occurs, it conducts surge current through its protection path and limits the voltage across the protected equipment.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Does Current Normally Flow Through an SPD?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The normal load current does not normally flow through a typical parallel-connected SPD.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">However, a small leakage or operating current may exist depending on the SPD technology and design.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Therefore, saying \u201cabsolutely no current flows through an SPD\u201d would not be technically precise.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Does an SPD Send All Surge Current to Ground?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Nicht unbedingt.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">An SPD may operate between line and neutral, line and earth, neutral and earth, line and line, or different DC conductors depending on its protection modes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The exact surge-current path depends on the SPD and electrical system configuration.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Can an SPD Be Connected Directly Across the Supply?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Many power SPDs are designed to be connected in parallel across the appropriate conductors of the supply.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">However, the exact wiring arrangement depends on the SPD type, system earthing arrangement, required overcurrent protection and manufacturer instructions.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Never determine the connection from a generic diagram alone.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Why Isn&#8217;t a Typical SPD Installed in Series With the Load?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">A normal parallel SPD is not designed to serve as the continuous main load-current path.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Installing an inline device requires a product specifically designed for that purpose, including suitable current, terminal, fault and thermal ratings.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Are In and Imax the Current of the Solar System?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Nein.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In and Imax are surge-discharge current parameters.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">They should not be confused with PV string operating current, short-circuit current or inverter input current.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Is a DC SPD Connected Differently From an AC SPD?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The general surge-protection principle is similar, but DC and AC systems have important differences.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The voltage rating, polarity, protection modes, earthing arrangement and internal SPD design may differ.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For PV systems, always use an SPD intended for the specific DC application and follow its wiring diagram.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Does an SPD Need a Ground Connection?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">It depends on the protection mode and system design.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Many power SPDs include protection paths involving PE, but not every surge protection mode is simply conductor-to-earth.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Use the manufacturer&#8217;s circuit diagram and the applicable earthing and bonding requirements.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Does SPD Wire Length Affect Protection?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Ja.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Long SPD connection conductors add inductance and can increase the voltage experienced by the protected equipment during a fast transient.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For this reason, connection conductors should generally be kept as short and direct as practical.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Wichtigste Erkenntnisse<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">If you only remember a few things from this article, remember these:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Most common Type 1 and Type 2 power SPDs are connected in parallel.<\/strong><\/li>\n\n\n\n<li><strong>A parallel-connected SPD does not normally carry the equipment&#8217;s normal load current.<\/strong><\/li>\n\n\n\n<li><strong>During a surge, the SPD conducts surge current through its designed protection path and limits the transient voltage.<\/strong><\/li>\n\n\n\n<li><strong>In and Imax are surge-discharge current ratings, not normal load-current ratings.<\/strong><\/li>\n\n\n\n<li><strong>Not every surge current path is simply \u201cto ground.\u201d The actual path depends on the SPD protection modes and system configuration.<\/strong><\/li>\n\n\n\n<li><strong>Series-connected surge protection products do exist, so \u201cSPDs can never be connected in series\u201d is technically incorrect.<\/strong><\/li>\n\n\n\n<li><strong>Short and direct SPD connections are important because conductor inductance can increase the effective voltage seen by the protected equipment.<\/strong><\/li>\n\n\n\n<li><strong>For PV DC systems, always follow the SPD wiring diagram, voltage rating, system earthing arrangement and manufacturer requirements.<\/strong><\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Schlussfolgerung<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">So, why is an SPD connected in parallel instead of series?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For a typical Type 1 or Type 2 <strong>Parallel geschalteter SPD<\/strong>, the normal load current does not pass through the SPD as it would through a series-connected device.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Under normal operating conditions, the SPD remains largely in standby.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">When a surge occurs, it conducts through its designed protection path and helps limit the voltage appearing across the protected equipment.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">That is fundamentally different from a fuse or circuit breaker, which normally carries the circuit current and is therefore installed in series.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">However, correct SPD installation involves more than simply choosing \u201cparallel.\u201d<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The SPD voltage rating, protection modes, location, conductor length, earthing and bonding arrangement, backup protection and manufacturer wiring diagram all affect the final protection performance.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For solar PV systems in particular, always use an SPD designed for the relevant DC application and verify the actual system voltage and wiring configuration before installation.<\/p>","protected":false},"excerpt":{"rendered":"<p>If you look at a typical surge protective device (SPD) installation, you may notice something different from a fuse or circuit breaker. A fuse or circuit breaker is normally installed in series with the circuit, so the load current passes through it. A typical power SPD is usually connected in parallel with the circuit it [&hellip;]<\/p>\n","protected":false},"author":7,"featured_media":4475,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35],"tags":[],"class_list":["post-4474","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/cnkuangya.com\/de\/wp-json\/wp\/v2\/posts\/4474","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cnkuangya.com\/de\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cnkuangya.com\/de\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cnkuangya.com\/de\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/cnkuangya.com\/de\/wp-json\/wp\/v2\/comments?post=4474"}],"version-history":[{"count":2,"href":"https:\/\/cnkuangya.com\/de\/wp-json\/wp\/v2\/posts\/4474\/revisions"}],"predecessor-version":[{"id":4486,"href":"https:\/\/cnkuangya.com\/de\/wp-json\/wp\/v2\/posts\/4474\/revisions\/4486"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cnkuangya.com\/de\/wp-json\/wp\/v2\/media\/4475"}],"wp:attachment":[{"href":"https:\/\/cnkuangya.com\/de\/wp-json\/wp\/v2\/media?parent=4474"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cnkuangya.com\/de\/wp-json\/wp\/v2\/categories?post=4474"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cnkuangya.com\/de\/wp-json\/wp\/v2\/tags?post=4474"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}