{"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\/it\/blog\/why-spd-connected-in-parallel\/","title":{"rendered":"Perch\u00e9 un SPD viene collegato in parallelo anzich\u00e9 in serie?"},"content":{"rendered":"<p class=\"wp-block-paragraph\">Se si osserva una tipica installazione di un dispositivo di protezione contro le sovratensioni (SPD), si potrebbe notare una differenza rispetto a un fusibile o a un interruttore magnetotermico.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Un fusibile o un interruttore magnetotermico \u00e8 normalmente installato in serie al circuito, in modo che la corrente di carico lo attraversi.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Un tipico SPD di potenza \u00e8 solitamente <strong>collegato in parallelo<\/strong> al circuito che protegge, motivo per cui molti installatori si chiedono perch\u00e9 un <strong>SPD sia collegato in parallelo anzich\u00e9 in serie<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Perch\u00e9?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">La risposta semplice \u00e8 che un SPD collegato in parallelo non deve trasportare la normale corrente di carico. In condizioni operative normali, rimane in uno stato ad alta impedenza. Quando si verifica una sovratensione transitoria, l'SPD inizia a condurre e fornisce un percorso a bassa impedenza per la corrente di sovratensione, limitando la tensione che raggiunge l'apparecchiatura protetta.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ecco perch\u00e9 il collegamento in parallelo \u00e8 ampiamente utilizzato per gli SPD di Tipo 1 e Tipo 2 nei sistemi di distribuzione elettrica e fotovoltaici.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tuttavia, \u201cSPD = sempre in parallelo\u201d non \u00e8 una regola assoluta. Esistono anche SPD collegati in serie e filtri di sovratensione per determinate applicazioni. In questo articolo, ci occupiamo principalmente del comune SPD di potenza collegato in parallelo utilizzato nei sistemi di distribuzione CA e nei sistemi solari fotovoltaici CC.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Risposta rapida: Collegamento SPD in parallelo vs. in serie<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Un tipico <strong>SPD collegato in parallelo<\/strong> \u00e8 progettato per rispondere a eventi di sovratensione temporanea senza trasportare la normale corrente operativa del carico.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In condizioni normali:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Fonte di alimentazione \u2192 Carico<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">L'SPD rimane in standby.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Quando si verifica una sovratensione, l'SPD modifica il proprio comportamento elettrico e conduce la corrente di sovratensione attraverso il suo percorso di protezione, contribuendo a limitare la tensione che si manifesta sulle apparecchiature sensibili.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Una disposizione in parallelo semplificata appare come segue:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Fonte di alimentazione \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 Carico\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\">Un tipico SPD collegato in parallelo viene installato attraverso il circuito protetto anzich\u00e9 direttamente nel percorso della corrente di carico normale.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">L'SPD \u00e8 collegato attraverso il circuito anzich\u00e9 inserito direttamente nel percorso della corrente di carico normale. <strong><a href=\"https:\/\/www.phoenixcontact.com\/assets\/c8428ddc-254d-40b8-a2f2-540ac13bd818\/index.html#0\" rel=\"noopener\">Fondamenti della protezione contro le sovratensioni di Phoenix Contact<\/a><\/strong> spiega inoltre che gli SPD possono essere installati in parallelo con l'apparecchiatura protetta o tra i conduttori pertinenti.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Eaton descrive gli SPD collegati in parallelo, o in derivazione, allo stesso modo: i loro conduttori di collegamento non trasportano la normale corrente di alimentazione, ma trasportano invece la corrente di breve durata associata agli eventi transitori.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Questa differenza fondamentale spiega perch\u00e9 la maggior parte degli SPD di potenza comuni viene installata in parallelo.<\/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\">Osserva come si comporta un tipico SPD durante il normale funzionamento e quando si verifica una sovratensione.<\/figcaption><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Cosa succede a un SPD durante il normale funzionamento?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Per comprendere il collegamento in parallelo, \u00e8 utile innanzitutto capire cosa fa l'SPD in assenza di sovratensioni.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Con tensione di sistema normale<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Durante il normale funzionamento, la tensione di sistema rimane al di sotto del livello in cui l'SPD conduce in modo significativo.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Per un SPD basato su MOV, l'elemento di protezione presenta un'impedenza relativamente elevata in condizioni di tensione normale.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ci\u00f2 significa che la corrente operativa principale continua a fluire attraverso il normale circuito di alimentazione verso il carico.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">L'SPD \u00e8 essenzialmente in standby.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Una visione semplificata \u00e8:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Alimentazione \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 Carico\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Ci\u00f2 non significa necessariamente che attraverso ogni SPD non scorra assolutamente alcuna corrente. A seconda della tecnologia e del design dell'SPD, pu\u00f2 essere presente una piccola corrente di dispersione o di funzionamento.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Il punto importante \u00e8:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>La normale corrente di carico non deve necessariamente fluire attraverso un tipico SPD collegato in parallelo.<\/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\">Cosa succede quando si verifica una sovratensione?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Una sovratensione \u00e8 un aumento di tensione di breve durata che pu\u00f2 essere causato da eventi come transitori legati ai fulmini o operazioni di commutazione.<\/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\">Se desideri una spiegazione pi\u00f9 approfondita su come gli elementi di protezione reagiscono alle sovratensioni transitorie, consulta la nostra guida su <strong><a href=\"https:\/\/cnkuangya.com\/it\/blog\/how-dc-spd-works-operating-principles-components-engineers-guide\/\">come funziona un SPD DC<\/a><\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">La sua impedenza diminuisce drasticamente rispetto alla condizione normale.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ci\u00f2 consente alla corrente di sovratensione di fluire attraverso il percorso di protezione disponibile e limita la tensione transitoria che si manifesta ai capi dell'apparecchiatura protetta.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Una rappresentazione semplificata \u00e8:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>                 Apparecchiatura\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Tuttavia, questo diagramma \u00e8 solo un esempio semplificato.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Un SPD fa <strong>non deviano sempre ogni sovratensione direttamente a terra<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A seconda dell'impianto elettrico e del design dell'SPD, possono esistere modalit\u00e0 di protezione tra:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Fase e neutro<\/li>\n\n\n\n<li>Fase e terra di protezione<\/li>\n\n\n\n<li>Neutro e terra di protezione<\/li>\n\n\n\n<li>Fase e fase<\/li>\n\n\n\n<li>DC positivo e DC negativo<\/li>\n\n\n\n<li>Conduttori DC e PE<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Per questo motivo, \u00e8 pi\u00f9 preciso affermare:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>L'SPD fornisce un percorso controllato per la corrente di sovratensione e limita la tensione transitoria attraverso l'apparecchiatura che protegge.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">L'esatto percorso della corrente dipende dalla configurazione dell'SPD e dalla topologia del sistema.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Perch\u00e9 un SPD \u00e8 collegato in parallelo?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Per capire perch\u00e9 un SPD viene collegato in parallelo, \u00e8 utile osservare cosa accade sia durante il normale funzionamento che durante un evento di sovratensione.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ci sono diverse ragioni importanti per cui un <strong>SPD collegato in parallelo<\/strong> \u00e8 ampiamente utilizzato nei sistemi di distribuzione dell'energia.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. L'SPD non deve trasportare la normale corrente di carico<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Questa \u00e8 una delle maggiori differenze tra un SPD e dispositivi come un interruttore automatico o un fusibile.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Immagina che un inverter operi normalmente a decine di ampere.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Con un tipico SPD collegato in parallelo, tale corrente operativa non deve passare continuamente attraverso l'SPD.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Invece:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Sorgente \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 Carico\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">L'SPD \u00e8 collegato in parallelo al circuito protetto.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ci\u00f2 significa che l'SPD pu\u00f2 essere selezionato principalmente in base ai requisiti di protezione dalle sovratensioni piuttosto che in base alla corrente operativa totale di ogni carico a valle.<\/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. L'SPD risponde principalmente agli eventi di sovratensione<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Un tipico SPD \u00e8 sensibile alla tensione.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Durante la normale tensione di sistema, rimane sostanzialmente inattivo.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Quando una tensione transitoria supera il normale campo operativo, gli elementi di protezione iniziano a condurre.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Questo \u00e8 fondamentalmente diverso da un fusibile, un interruttore automatico o un sezionatore.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ad esempio:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Fusibile<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Sorgente \u2192 Fusibile \u2192 Carico\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Interruttore automatico<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Sorgente \u2192 Interruttore \u2192 Carico\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Tipico SPD in parallelo<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Sorgente \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 Carico\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Un fusibile o un interruttore automatico deve normalmente trasportare la corrente del circuito poich\u00e9 si trova fisicamente nel percorso del carico.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Un SPD in parallelo non lo fa.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">3. Il collegamento in parallelo fornisce un percorso per la corrente di sovratensione.<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Lo scopo di un SPD non \u00e8 quello di \u201cbloccare\u201d ogni sovratensione prima che raggiunga il carico.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Invece, un SPD limitatore di tensione risponde all'aumento della tensione transitoria e conduce la corrente di sovratensione.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Questa azione limita la tensione attraverso il circuito protetto.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ad esempio, in un sistema fotovoltaico semplificato:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Campo FV \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 Inverter\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Durante il normale funzionamento, l'energia fotovoltaica continua a fluire verso l'inverter.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Durante un evento di sovratensione, l'SPD conduce in base alla sua modalit\u00e0 di protezione e contribuisce a mantenere la tensione transitoria a un livello inferiore rispetto a quello che raggiungerebbe altrimenti.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Questo \u00e8 il motivo fondamentale per cui l'SPD viene posizionato in parallelo al circuito.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">4. L'SPD non fa normalmente parte del percorso di alimentazione principale.<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Poich\u00e9 il tipico SPD \u00e8 collegato come una derivazione in parallelo, non diventa il normale percorso conduttivo tra la sorgente e il carico.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ci\u00f2 comporta un importante vantaggio pratico.<\/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\">Naturalmente, ci\u00f2 non significa che un SPD possa essere ignorato dopo l'installazione.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Gli SPD possono degradarsi o scollegarsi in seguito a sollecitazioni elettriche anomale, pertanto il loro stato di funzionamento deve essere controllato periodicamente.<\/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\">Comprendere perch\u00e9 un SPD \u00e8 collegato in parallelo aiuta anche a spiegare perch\u00e9 un tipico SPD collegato in derivazione non viene posizionato in serie al normale percorso del carico.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Gli interruttori automatici e i fusibili sono normalmente installati in serie perch\u00e9 devono trasportare la corrente del circuito. Un tipico SPD in parallelo \u00e8 progettato per una funzione diversa.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">La normale corrente di carico dovrebbe passare attraverso un dispositivo in serie<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Un vero collegamento in serie si presenta cos\u00ec:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Sorgente \u2192 Dispositivo \u2192 Carico\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Se l'intero gruppo SPD venisse inserito nel percorso del carico, l'SPD dovrebbe essere in grado di gestire la corrente di carico continua.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">I suoi conduttori, i terminali, il design termico, le prestazioni in caso di cortocircuito e il comportamento in caso di guasto dovrebbero essere tutti progettati per tale applicazione.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Non \u00e8 cos\u00ec che viene normalmente utilizzato il comune SPD in parallelo di Tipo 1 o Tipo 2 su guida DIN.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Le correnti nominali di scarica degli SPD non sono correnti di carico<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Questo \u00e8 un punto particolarmente importante quando si legge la targhetta di un SPD.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Supponiamo che un SPD sia contrassegnato come segue:<\/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\">e<\/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 e Imax descrivono le prestazioni della corrente di scarica da sovratensione, non la corrente operativa normale del circuito protetto.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Se queste specifiche degli SPD risultano ancora poco chiare, la nostra <strong><a href=\"https:\/\/cnkuangya.com\/it\/blog\/dc-spd-specifications\/\">guida alle specifiche degli SPD in corrente continua<\/a><\/strong> spiega pi\u00f9 dettagliatamente Ucpv, In, Imax, Up e Iscpv.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Questi numeri non <strong>non<\/strong> significano che l'SPD \u00e8 progettato per trasportare continuamente 20 kA o 40 kA di corrente di carico normale.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Per gli SPD di Tipo 2, <strong>In<\/strong> si riferisce alla corrente nominale di scarica associata a un impulso di corrente 8\/20 \u03bcs, mentre <strong>Imax<\/strong> si riferisce alla corrente massima di scarica associata a un impulso 8\/20 \u03bcs.<\/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\">Quindi:<\/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 e Imax sono valori nominali di corrente di scarica da sovratensione. Non rappresentano la normale corrente operativa del carico.<\/strong><\/p>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">Questa distinzione \u00e8 molto importante quando si seleziona o si spiega un SPD.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Ci\u00f2 significa che gli SPD collegati in serie non esistono?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">No.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Questa \u00e8 un'eccezione importante.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Sebbene i comuni SPD di alimentazione di Tipo 1 e Tipo 2 discussi in questo articolo siano generalmente installati in parallelo, esistono anche gruppi SPD collegati in serie e filtri di sovratensione collegati in serie.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Schneider Electric osserva che i prodotti collegati in serie vengono solitamente installati in linea vicino a carichi specifici, mentre gli SPD collegati in parallelo rappresentano la configurazione pi\u00f9 comune nei quadri elettrici e nei pannelli di distribuzione.<\/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\">Pertanto, sarebbe errato affermare:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>\u201cUn SPD non pu\u00f2 mai essere collegato in serie.\u201d<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Un'affermazione tecnicamente pi\u00f9 accurata \u00e8:<\/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>La maggior parte degli SPD di Tipo 1 e Tipo 2 per la distribuzione di potenza sono collegati in parallelo, sebbene esistano anche prodotti di protezione contro le sovratensioni collegati in serie, progettati specificamente per applicazioni particolari.<\/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\">Collegamento in parallelo vs. in serie: confronto semplice<\/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\">La tabella sottostante mostra come un tipico <strong>SPD collegato in parallelo<\/strong> differisce da un dispositivo installato direttamente nel percorso della corrente di carico normale.<\/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\">Un tipico SPD in parallelo \u00e8 collegato ai capi del circuito protetto, mentre un dispositivo collegato in serie si trova direttamente nel percorso della corrente normale.<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Caratteristica<\/th><th>Tipico SPD in parallelo<\/th><th>Dispositivo collegato in serie<\/th><\/tr><\/thead><tbody><tr><td>Collegato direttamente nel percorso di carico normale<\/td><td>No<\/td><td>S\u00ec<\/td><\/tr><tr><td>La corrente di carico normale attraversa l'intero dispositivo<\/td><td>No<\/td><td>S\u00ec<\/td><\/tr><tr><td>Configurazione comune per SPD di potenza di Tipo 1 \/ Tipo 2<\/td><td>S\u00ec<\/td><td>Meno comune<\/td><\/tr><tr><td>Scopo principale<\/td><td>Limita la sovratensione transitoria fornendo un percorso per la corrente di scarica<\/td><td>Dipende dal design del prodotto<\/td><\/tr><tr><td>La corrente nominale continua \u00e8 critica per l'intero dispositivo<\/td><td>Solitamente non nello stesso modo di un dispositivo in linea<\/td><td>S\u00ec<\/td><\/tr><tr><td>La lunghezza del cavo di installazione influisce sulla protezione<\/td><td>S\u00ec<\/td><td>Internal arrangement may reduce external parallel lead-length effects<\/td><\/tr><tr><td>Applicazioni tipiche<\/td><td>Distribution boards, equipment entrances, PV systems<\/td><td>Selected sensitive loads or specialized protection\/filtering applications<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The important point is not that one method is universally \u201cgood\u201d and the other is \u201cbad.\u201d<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">They are different product architectures.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For a normal DIN-rail power SPD, however, parallel connection is usually the expected installation method.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">How Is an SPD Connected in a Solar PV DC System?<\/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\">A DC SPD is typically connected in parallel with the PV circuit according to the SPD configuration and manufacturer wiring diagram.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">However, DC SPD wiring deserves extra care.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">It is not correct to assume that every PV SPD is simply wired:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>DC+ \u2192 SPD \u2192 PE\nDC\u2212 \u2192 SPD \u2192 PE\n<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">The actual internal protection circuit may be different.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Depending on the product and PV system configuration, the SPD may provide protection modes between:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>DC+ and PE<\/li>\n\n\n\n<li>DC\u2212 and PE<\/li>\n\n\n\n<li>DC+ and DC\u2212<\/li>\n\n\n\n<li>A combination of these paths<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Different SPD circuit arrangements are used for different earthing systems and PV architectures.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For a PV SPD connected in parallel, the exact terminal arrangement still depends on the SPD design, system topology, and manufacturer wiring diagram.<\/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\">For photovoltaic DC applications, the dedicated IEC product standard is IEC 61643-31. DEHN also identifies IEC 60364-7-712 and IEC 60364-5-53 among the relevant installation standards for PV and low-voltage SPD applications.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Do Not Copy an AC SPD Wiring Diagram to a DC SPD<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Although AC and DC SPDs are based on similar surge-protection principles, the systems are not interchangeable.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">DC systems present additional challenges because direct current has no natural zero crossing, which makes interruption of DC arcs more difficult.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For this reason, the SPD must be specifically suitable for the DC voltage, system configuration and application.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Always check:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Tensione massima di funzionamento continuo<\/li>\n\n\n\n<li>DC polarity and terminal markings<\/li>\n\n\n\n<li>SPD type<\/li>\n\n\n\n<li>Protection modes<\/li>\n\n\n\n<li>Sistema di messa a terra<\/li>\n\n\n\n<li>Short-circuit requirements<\/li>\n\n\n\n<li>Manufacturer wiring diagram<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">before installation.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Example: Reading a KUANGYA Type 2 DC SPD<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Using a KUANGYA KYPV\/1000 Type 2 DC SPD as an example, the nameplate may include parameters such as:<\/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 is the maximum continuous operating voltage specified for the SPD.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The system voltage and possible operating conditions must be considered when choosing a suitable voltage rating.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">In<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">In is the nominal discharge current.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For a Type 2 SPD, it is associated with an 8\/20 \u03bcs impulse-current waveform.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Imax<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Imax is the maximum discharge current specified for the SPD, also associated with the 8\/20 \u03bcs waveform for this type of device.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Imax is equal to or greater than In.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Su<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Up is the voltage protection level.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">It indicates the voltage-limiting performance of the SPD under specified test conditions.<\/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 and 40 kA Imax do not mean that 20 kA or 40 kA continuously flows through the SPD during normal operation.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">These are transient surge-current parameters.<\/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\">No.<\/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\">Secondo <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\/it\/blog\/spd-distance-from-inverter\/\">La distanza tra l'SPD e l'inverter \u00e8 rilevante?<\/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\/it\/blog\/solar-inverter-built-in-spd\/\">L'inverter solare \u00e8 dotato di un SPD CC integrato: \u00e8 ancora necessario un SPD esterno?<\/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\">Secondo <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>Fusibile<\/li>\n\n\n\n<li>Interruttore automatico<\/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>Tensione di sistema<\/li>\n\n\n\n<li>Luogo di installazione<\/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> = induttanza del conduttore<\/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\">La lezione pratica \u00e8 molto pi\u00f9 semplice:<\/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\/it\/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\/it\/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\">Interruttore automatico<\/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\">Domande frequenti<\/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\">Non necessariamente.<\/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\">No.<\/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\">S\u00ec.<\/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\">Punti di forza<\/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\">Conclusione<\/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>SPD collegato in parallelo<\/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\/it\/wp-json\/wp\/v2\/posts\/4474","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cnkuangya.com\/it\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cnkuangya.com\/it\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cnkuangya.com\/it\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/cnkuangya.com\/it\/wp-json\/wp\/v2\/comments?post=4474"}],"version-history":[{"count":2,"href":"https:\/\/cnkuangya.com\/it\/wp-json\/wp\/v2\/posts\/4474\/revisions"}],"predecessor-version":[{"id":4486,"href":"https:\/\/cnkuangya.com\/it\/wp-json\/wp\/v2\/posts\/4474\/revisions\/4486"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cnkuangya.com\/it\/wp-json\/wp\/v2\/media\/4475"}],"wp:attachment":[{"href":"https:\/\/cnkuangya.com\/it\/wp-json\/wp\/v2\/media?parent=4474"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cnkuangya.com\/it\/wp-json\/wp\/v2\/categories?post=4474"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cnkuangya.com\/it\/wp-json\/wp\/v2\/tags?post=4474"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}