{"id":29628,"date":"2026-06-30T13:21:18","date_gmt":"2026-06-30T05:21:18","guid":{"rendered":"https:\/\/www.cnspd.com\/?p=29628"},"modified":"2026-07-01T11:07:53","modified_gmt":"2026-07-01T03:07:53","slug":"spd-uc-selection-guide-for-distribution-boards-and-oem-orders","status":"publish","type":"post","link":"https:\/\/www.cnspd.com\/fr\/spd-uc-selection-guide\/","title":{"rendered":"Guide de s\u00e9lection SPD Uc pour tableaux de distribution et commandes OEM"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"29628\" class=\"elementor elementor-29628\" data-elementor-post-type=\"post\">\n\t\t\t\t<div class=\"elementor-element elementor-element-6e4ce4d e-flex e-con-boxed e-con e-parent\" data-id=\"6e4ce4d\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-d3effbb elementor-widget elementor-widget-html\" data-id=\"d3effbb\" 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}\r\n    .cn-article-intro { font-size: 17px !important; }\r\n    .cn-toc,\r\n    .cn-note,\r\n    .cn-warning,\r\n    .cn-good,\r\n    .cn-checklist,\r\n    .cn-cta {\r\n      border-radius: 16px;\r\n      padding: 17px;\r\n    }\r\n    .cn-table { min-width: 720px; }\r\n    .cn-step {\r\n      grid-template-columns: 36px 1fr;\r\n      gap: 10px;\r\n    }\r\n    .cn-btn { width: 100% !important; }\r\n\r\n    .cn-table-wrap.cn-mobile-hide-table {\r\n      display: none;\r\n    }\r\n\r\n    .cn-mobile-uc-cards {\r\n      display: grid;\r\n      gap: 12px;\r\n      margin: 20px 0 26px;\r\n    }\r\n\r\n    .cn-mobile-uc-card {\r\n      border: 1px solid var(--cn-border);\r\n      border-radius: 18px;\r\n      background: #ffffff;\r\n      padding: 16px;\r\n    }\r\n\r\n    .cn-mobile-uc-card strong {\r\n      display: inline-flex;\r\n      align-items: center;\r\n      justify-content: center;\r\n      min-width: 58px;\r\n      height: 34px;\r\n      border-radius: 999px;\r\n      background: var(--cn-blue);\r\n      color: #ffffff;\r\n      font-size: 16px;\r\n      font-weight: 850;\r\n      margin-bottom: 10px;\r\n    }\r\n\r\n    .cn-mobile-uc-card h3 {\r\n      font-size: 18px;\r\n      color: var(--cn-text);\r\n      margin: 0 0 8px;\r\n      padding: 0;\r\n      letter-spacing: -0.01em;\r\n    }\r\n\r\n    .cn-mobile-uc-card p {\r\n      font-size: 15.5px;\r\n      margin-bottom: 8px;\r\n      color: var(--cn-muted);\r\n    }\r\n\r\n    .cn-mobile-watch {\r\n      color: #8a5b00;\r\n      background: #fff8ea;\r\n      border: 1px solid #f0d49d;\r\n      border-radius: 12px;\r\n      padding: 10px;\r\n      margin-top: 10px;\r\n      font-size: 14.5px;\r\n      line-height: 1.55;\r\n    }\r\n\r\n    .cn-uc-cluster span {\r\n      font-size: 14.5px;\r\n    }\r\n  }\r\n<\/style>\r\n\r\n<article class=\"cn-article\">\r\n\r\n  <div class=\"cn-article-label\">Selection Guide<\/div>\r\n\r\n  <p class=\"cn-article-intro\">\r\n    Choosing the right SPD Uc is important for distribution boards, industrial panels, and OEM surge protection orders.\r\n    This guide explains how to compare 275V, 320V, 385V, and 440V AC SPD options without oversimplifying the selection.\r\n  <\/p>\r\n\r\n  <div class=\"cn-article-meta\">\r\n    <span>For distribution boards<\/span>\r\n    <span>For OEM orders<\/span>\r\n    <span>For panel builders<\/span>\r\n    <span>Reading time: 7\u20139 minutes<\/span>\r\n  <\/div>\r\n\r\n  <div class=\"cn-note\">\r\n    <p>\r\n      <strong>Quick answer:<\/strong> For stable 230\/400V distribution boards, 275V is commonly used as a starting point.\r\n      For moderate voltage fluctuation, 320V may be considered.\r\n      For unstable grids or industrial panels, 385V is often checked.\r\n      For higher-voltage or special AC systems, 440V should be selected only after confirming the system design and datasheet.\r\n    <\/p>\r\n  <\/div>\r\n\r\n  <nav class=\"cn-toc\">\r\n    <div class=\"cn-toc-title\">In this guide<\/div>\r\n    <ol>\r\n      <li><a href=\"#quick-answer\">Quick answer: 275V, 320V, 385V, or 440V?<\/a><\/li>\r\n      <li><a href=\"#uc-mcov\">Uc vs MCOV: why buyers see different terms<\/a><\/li>\r\n      <li><a href=\"#what-is-uc\">What does Uc mean in SPD selection?<\/a><\/li>\r\n      <li><a href=\"#selection-factors\">Key factors that affect Uc selection<\/a><\/li>\r\n      <li><a href=\"#how-to-choose\">How to choose SPD Uc for distribution boards<\/a><\/li>\r\n      <li><a href=\"#oem-orders\">What OEM buyers should confirm<\/a><\/li>\r\n      <li><a href=\"#mistakes\">Common mistakes to avoid<\/a><\/li>\r\n      <li><a href=\"#faq\">FAQ<\/a><\/li>\r\n    <\/ol>\r\n  <\/nav>\r\n\r\n  <section id=\"quick-answer\">\r\n    <div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter ez-toc-custom ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/fr\/spd-uc-selection-guide\/#quick-answer-which-spd-uc-should-you-choose\" >Quick Answer: Which SPD Uc Should You Choose?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/fr\/spd-uc-selection-guide\/#uc-vs-mcov-why-buyers-see-different-terms\" >Uc vs MCOV: Why Buyers See Different Terms<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/fr\/spd-uc-selection-guide\/#what-does-uc-mean-in-spd-selection\" >What Does Uc Mean in SPD Selection?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/fr\/spd-uc-selection-guide\/#key-factors-that-affect-uc-selection\" >Key Factors That Affect Uc Selection<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/fr\/spd-uc-selection-guide\/#how-to-choose-spd-uc-for-distribution-boards\" >How to Choose SPD Uc for Distribution Boards<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/fr\/spd-uc-selection-guide\/#typical-selection-scenarios\" >Typical Selection Scenarios<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/fr\/spd-uc-selection-guide\/#what-oem-buyers-should-confirm-before-ordering\" >What OEM Buyers Should Confirm Before Ordering<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/fr\/spd-uc-selection-guide\/#common-mistakes-when-choosing-spd-uc\" >Common Mistakes When Choosing SPD Uc<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/fr\/spd-uc-selection-guide\/#faq-spd-uc-selection\" >FAQ: SPD Uc Selection<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/fr\/spd-uc-selection-guide\/#related-spd-uc-mcov-guides\" >Related SPD Uc \/ MCOV Guides<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"quick-answer-which-spd-uc-should-you-choose\"><\/span>Quick Answer: Which SPD Uc Should You Choose?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      Most buyers do not only want a definition of Uc.\r\n      They want to know which voltage version is suitable for their panel, project, or OEM order.\r\n    <\/p>\r\n\r\n    <p>\r\n      The table below gives a practical starting point.\r\n      The final choice should still be checked with the actual system voltage, earthing system, connection mode, grid condition, and SPD datasheet.\r\n    <\/p>\r\n\r\n    <div class=\"cn-table-wrap cn-mobile-hide-table\">\r\n      <table class=\"cn-table\">\r\n        <thead>\r\n          <tr>\r\n            <th>SPD Uc<\/th>\r\n            <th>Best starting point<\/th>\r\n            <th>Choose it when<\/th>\r\n            <th>Watch out<\/th>\r\n          <\/tr>\r\n        <\/thead>\r\n        <tbody>\r\n          <tr>\r\n            <td>275V<\/td>\r\n            <td>Stable 230\/400V distribution boards.<\/td>\r\n            <td>\r\n              The line-to-neutral voltage is around 230V, the supply is stable, and the project needs a standard AC SPD for normal distribution protection.\r\n            <\/td>\r\n            <td>\r\n              Do not use it blindly where the grid often runs high or temporary overvoltage is expected.\r\n            <\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>320V<\/td>\r\n            <td>230\/400V systems with moderate voltage fluctuation.<\/td>\r\n            <td>\r\n              The buyer wants more continuous voltage margin than 275V, especially for export panels or less stable utility supply.\r\n            <\/td>\r\n            <td>\r\n              Check the voltage protection level Up. Higher Uc may change the protection performance.\r\n            <\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>385V<\/td>\r\n            <td>Industrial panels, unstable grids, or generator-fed systems.<\/td>\r\n            <td>\r\n              The real operating voltage may run high, and early SPD ageing is a concern.\r\n            <\/td>\r\n            <td>\r\n              It is not automatically better than 275V or 320V. Confirm the protected equipment and datasheet.\r\n            <\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>440V<\/td>\r\n            <td>Higher-voltage or special AC applications.<\/td>\r\n            <td>\r\n              The system design, wiring mode, or OEM requirement needs a higher continuous voltage rating.\r\n            <\/td>\r\n            <td>\r\n              Do not choose 440V only because it looks safer. It may not give the most suitable protection level for all panels.\r\n            <\/td>\r\n          <\/tr>\r\n        <\/tbody>\r\n      <\/table>\r\n    <\/div>\r\n\r\n    <div class=\"cn-mobile-uc-cards\">\r\n      <div class=\"cn-mobile-uc-card\">\r\n        <strong>275V<\/strong>\r\n        <h3>Stable 230\/400V distribution boards<\/h3>\r\n        <p>\r\n          Best used as a starting point when the line-to-neutral voltage is around 230V and the supply is stable.\r\n        <\/p>\r\n        <div class=\"cn-mobile-watch\">\r\n          Watch out: do not use it blindly where the grid often runs high or temporary overvoltage is expected.\r\n        <\/div>\r\n      <\/div>\r\n\r\n      <div class=\"cn-mobile-uc-card\">\r\n        <strong>320V<\/strong>\r\n        <h3>Moderate voltage fluctuation<\/h3>\r\n        <p>\r\n          Consider it when the buyer wants more continuous voltage margin than 275V, especially for export panels.\r\n        <\/p>\r\n        <div class=\"cn-mobile-watch\">\r\n          Watch out: check the voltage protection level Up. Higher Uc may change the protection performance.\r\n        <\/div>\r\n      <\/div>\r\n\r\n      <div class=\"cn-mobile-uc-card\">\r\n        <strong>385V<\/strong>\r\n        <h3>Unstable grids or industrial panels<\/h3>\r\n        <p>\r\n          Often checked when the real operating voltage may run high, or when early SPD ageing is a concern.\r\n        <\/p>\r\n        <div class=\"cn-mobile-watch\">\r\n          Watch out: it is not automatically better than 275V or 320V. Confirm the protected equipment and datasheet.\r\n        <\/div>\r\n      <\/div>\r\n\r\n      <div class=\"cn-mobile-uc-card\">\r\n        <strong>440V<\/strong>\r\n        <h3>Higher-voltage or special AC systems<\/h3>\r\n        <p>\r\n          Used when the system design, wiring mode, or OEM requirement needs a higher continuous voltage rating.\r\n        <\/p>\r\n        <div class=\"cn-mobile-watch\">\r\n          Watch out: do not choose 440V only because it looks safer. It is not a universal replacement.\r\n        <\/div>\r\n      <\/div>\r\n    <\/div>\r\n\r\n    <div class=\"cn-cta\">\r\n      <div class=\"cn-cta-title\">Need help confirming the right Uc?<\/div>\r\n      <p>\r\n        Send us your system voltage, earthing system, pole structure, and application.\r\n        We can help check whether 275V, 320V, 385V, or 440V is more suitable for your distribution board or OEM SPD order.\r\n      <\/p>\r\n      <a class=\"cn-btn leeyee-site-popup-btn\" href=\"javascript:void(0);\"><span>Request SPD Uc Recommendation<\/span><\/a>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"uc-mcov\">\r\n    <h2><span class=\"ez-toc-section\" id=\"uc-vs-mcov-why-buyers-see-different-terms\"><\/span>Uc vs MCOV: Why Buyers See Different Terms<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      In many IEC-style SPD datasheets, buyers usually see the term <strong>Uc<\/strong>.\r\n      In UL-style SPD documents, buyers may see <strong>MCOV<\/strong>, which means maximum continuous operating voltage.\r\n    <\/p>\r\n\r\n    <p>\r\n      Uc and MCOV serve a similar selection role.\r\n      Both help buyers confirm whether an SPD can continuously withstand the real service voltage.\r\n      The exact marking and documentation should follow the applicable standard and target market.\r\n    <\/p>\r\n\r\n    <p>\r\n      This is important for OEM orders.\r\n      The product label, datasheet, model name, and technical file should use the correct voltage term for the market where the SPD will be sold.\r\n    <\/p>\r\n\r\n    <div class=\"cn-table-wrap\">\r\n      <table class=\"cn-table\">\r\n        <thead>\r\n          <tr>\r\n            <th>Buyer situation<\/th>\r\n            <th>Term often seen<\/th>\r\n            <th>What to confirm<\/th>\r\n          <\/tr>\r\n        <\/thead>\r\n        <tbody>\r\n          <tr>\r\n            <td>IEC-style markets<\/td>\r\n            <td>Uc<\/td>\r\n            <td>Confirm system voltage, earthing system, SPD connection mode, and the Uc value on the datasheet.<\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>UL-style markets<\/td>\r\n            <td>MCOV<\/td>\r\n            <td>Confirm service voltage, MCOV rating, product marking, and required documentation.<\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>OEM export orders<\/td>\r\n            <td>Uc \/ MCOV<\/td>\r\n            <td>Confirm the target market before printing labels, datasheets, packaging, and model codes.<\/td>\r\n          <\/tr>\r\n        <\/tbody>\r\n      <\/table>\r\n    <\/div>\r\n\r\n    <div class=\"cn-warning\">\r\n      <p>\r\n        <strong>Professional note:<\/strong> do not mix Uc and MCOV labels casually.\r\n        The rating, marking, and documentation should match the target market and product approval route.\r\n      <\/p>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"what-is-uc\">\r\n    <h2><span class=\"ez-toc-section\" id=\"what-does-uc-mean-in-spd-selection\"><\/span>What Does Uc Mean in SPD Selection?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      Uc means <strong>maximum continuous operating voltage<\/strong>.\r\n      It is the maximum voltage that the SPD can withstand continuously during normal operation.\r\n    <\/p>\r\n\r\n    <p>\r\n      For buyers, Uc answers a practical question:\r\n      <strong>can this SPD stay connected to the real power system without ageing too fast or operating too early?<\/strong>\r\n    <\/p>\r\n\r\n    <p>\r\n      Uc is different from In, Imax, and Up.\r\n      In and Imax describe surge current capability.\r\n      Up describes the voltage protection level during a surge.\r\n      Uc describes the continuous voltage that the SPD can tolerate before surge events happen.\r\n    <\/p>\r\n\r\n    <div class=\"cn-warning\">\r\n      <p>\r\n        <strong>Important:<\/strong> do not choose Uc by looking at only one number on the panel.\r\n        A 230\/400V system, a 400\/415V system, a TT system, and an IT system may require different SPD structures and different voltage checks.\r\n      <\/p>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"selection-factors\">\r\n    <h2><span class=\"ez-toc-section\" id=\"key-factors-that-affect-uc-selection\"><\/span>Key Factors That Affect Uc Selection<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      Uc selection should stay practical, but it should not be oversimplified.\r\n      Before confirming the SPD model, check the main factors below.\r\n    <\/p>\r\n\r\n    <p>\r\n      In IEC-style SPD selection, Uc should be checked together with the system voltage, earthing system, and SPD connection mode.\r\n      In UL-style documents, buyers may see MCOV for a similar selection role.\r\n    <\/p>\r\n\r\n    <div class=\"cn-table-wrap\">\r\n      <table class=\"cn-table\">\r\n        <thead>\r\n          <tr>\r\n            <th>Factor<\/th>\r\n            <th>Why it matters<\/th>\r\n            <th>What to send the supplier<\/th>\r\n          <\/tr>\r\n        <\/thead>\r\n        <tbody>\r\n          <tr>\r\n            <td>System voltage<\/td>\r\n            <td>It defines the normal voltage the SPD may continuously see.<\/td>\r\n            <td>230\/400V, 400\/415V, 480V, or another system voltage.<\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>Earthing system<\/td>\r\n            <td>TN-S, TN-C-S, TT, and IT systems can change the SPD connection and voltage requirement.<\/td>\r\n            <td>TN-S, TN-C-S, TT, IT, or special earthing arrangement.<\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>Connection mode<\/td>\r\n            <td>The voltage across the SPD depends on how it is connected.<\/td>\r\n            <td>L-N, L-PE, N-PE, 3+1, 4P, or the panel wiring diagram.<\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>Grid condition<\/td>\r\n            <td>A high or unstable supply may stress a low-Uc SPD during normal operation.<\/td>\r\n            <td>Stable grid, unstable grid, generator supply, or possible temporary overvoltage.<\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>Target market<\/td>\r\n            <td>The market may affect the label, datasheet, certification, and term used.<\/td>\r\n            <td>IEC-style market, UL-style market, or local-market requirement.<\/td>\r\n          <\/tr>\r\n        <\/tbody>\r\n      <\/table>\r\n    <\/div>\r\n\r\n    <div class=\"cn-good\">\r\n      <p>\r\n        <strong>Simple professional rule:<\/strong> choose the lowest Uc that can safely withstand the real continuous operating voltage and expected fluctuation of the system.\r\n        Then confirm Up, In, Imax, SPD type, backup protection, and certification.\r\n      <\/p>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"how-to-choose\">\r\n    <h2><span class=\"ez-toc-section\" id=\"how-to-choose-spd-uc-for-distribution-boards\"><\/span>How to Choose SPD Uc for Distribution Boards<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      A good Uc choice should match the real voltage that the SPD module will see in normal service.\r\n      It should also leave enough margin for expected voltage fluctuation.\r\n    <\/p>\r\n\r\n    <p>\r\n      Use the following steps before confirming the final AC SPD model.\r\n    <\/p>\r\n\r\n    <div class=\"cn-steps\">\r\n      <div class=\"cn-step\">\r\n        <div class=\"cn-step-num\"><\/div>\r\n        <div class=\"cn-step-content\">\r\n          <strong>Confirm the real system voltage<\/strong>\r\n          <p>Check whether the panel is 230\/400V, 400\/415V, 480V, or another system. Do not assume that every SPD module sees the line-to-line voltage.<\/p>\r\n        <\/div>\r\n      <\/div>\r\n      <div class=\"cn-step\">\r\n        <div class=\"cn-step-num\"><\/div>\r\n        <div class=\"cn-step-content\">\r\n          <strong>Confirm the earthing system<\/strong>\r\n          <p>TN-S, TN-C-S, TT, and IT systems can require different SPD pole structures and connection methods. This can affect Uc selection.<\/p>\r\n        <\/div>\r\n      <\/div>\r\n      <div class=\"cn-step\">\r\n        <div class=\"cn-step-num\"><\/div>\r\n        <div class=\"cn-step-content\">\r\n          <strong>Check the SPD connection mode<\/strong>\r\n          <p>Confirm whether the SPD is connected L-N, L-PE, N-PE, 3+1, 4P, or another arrangement. The voltage across the SPD depends on this connection.<\/p>\r\n        <\/div>\r\n      <\/div>\r\n      <div class=\"cn-step\">\r\n        <div class=\"cn-step-num\"><\/div>\r\n        <div class=\"cn-step-content\">\r\n          <strong>Check grid stability<\/strong>\r\n          <p>If the grid often runs high, or if the panel is used with generators or unstable utility supply, a higher Uc may be considered to reduce early SPD stress.<\/p>\r\n        <\/div>\r\n      <\/div>\r\n      <div class=\"cn-step\">\r\n        <div class=\"cn-step-num\"><\/div>\r\n        <div class=\"cn-step-content\">\r\n          <strong>Check Up and equipment sensitivity<\/strong>\r\n          <p>A higher Uc is not always better. Check the voltage protection level Up and make sure the downstream equipment can still be protected properly.<\/p>\r\n        <\/div>\r\n      <\/div>\r\n      <div class=\"cn-step\">\r\n        <div class=\"cn-step-num\"><\/div>\r\n        <div class=\"cn-step-content\">\r\n          <strong>Confirm the model with the supplier<\/strong>\r\n          <p>For OEM orders, confirm Uc or MCOV, pole structure, wiring diagram, label content, and datasheet before mass production.<\/p>\r\n        <\/div>\r\n      <\/div>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section>\r\n    <h2><span class=\"ez-toc-section\" id=\"typical-selection-scenarios\"><\/span>Typical Selection Scenarios<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>The examples below are not fixed rules. They help buyers narrow down the first choice before checking the final datasheet.<\/p>\r\n\r\n    <div class=\"cn-table-wrap\">\r\n      <table class=\"cn-table\">\r\n        <thead>\r\n          <tr>\r\n            <th>Application<\/th>\r\n            <th>Common Uc direction<\/th>\r\n            <th>Why buyers choose it<\/th>\r\n          <\/tr>\r\n        <\/thead>\r\n        <tbody>\r\n          <tr>\r\n            <td>Stable 230\/400V distribution board<\/td>\r\n            <td>275V is commonly used<\/td>\r\n            <td>The supply is stable, the line-to-neutral voltage is around 230V, and the buyer needs a standard AC SPD for normal distribution protection.<\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>Export electrical panel<\/td>\r\n            <td>320V or 385V may be considered<\/td>\r\n            <td>The panel may be installed in markets where utility voltage is less stable. Buyers may want more continuous voltage margin.<\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>Industrial control cabinet<\/td>\r\n            <td>320V, 385V, or 440V depending on system<\/td>\r\n            <td>Industrial sites may have higher voltage fluctuation, generator supply, or more complex earthing conditions.<\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>400\/415V industrial system<\/td>\r\n            <td>385V or 440V may be checked<\/td>\r\n            <td>The final choice depends on the connection mode, earthing system, and the voltage each SPD protection mode will continuously see.<\/td>\r\n          <\/tr>\r\n          <tr>\r\n            <td>OEM private label SPD order<\/td>\r\n            <td>Confirm by target market<\/td>\r\n            <td>Uc affects label, datasheet, model naming, certification documents, and after-sales risk. Confirm it before production.<\/td>\r\n          <\/tr>\r\n        <\/tbody>\r\n      <\/table>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"oem-orders\">\r\n    <h2><span class=\"ez-toc-section\" id=\"what-oem-buyers-should-confirm-before-ordering\"><\/span>What OEM Buyers Should Confirm Before Ordering<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      For OEM and private label orders, Uc is not just a technical parameter.\r\n      It affects the product model, label, datasheet, packaging, wiring diagram, and customer support after delivery.\r\n    <\/p>\r\n\r\n    <p>\r\n      The target market also matters.\r\n      An IEC-style market, a UL-style market, or a local distribution project may require different markings, documents, and voltage confirmation.\r\n    <\/p>\r\n\r\n    <div class=\"cn-checklist\">\r\n      <ul>\r\n        <li>Nominal system voltage: 230\/400V, 400\/415V, 480V, or other.<\/li>\r\n        <li>Earthing system: TN-S, TN-C-S, TT, IT, or special system.<\/li>\r\n        <li>SPD type: Type 1, Type 2, or Type 1+2.<\/li>\r\n        <li>Pole structure: 1P, 1P+N, 2P, 3P, 3P+N, or 4P.<\/li>\r\n        <li>Connection mode: L-N, L-PE, N-PE, 3+1, 4P, or other.<\/li>\r\n        <li>Expected voltage fluctuation or temporary overvoltage condition.<\/li>\r\n        <li>Required Uc, MCOV, Up, In, Imax, and short-circuit protection arrangement.<\/li>\r\n        <li>Required standard, test report, or certification for the target market.<\/li>\r\n        <li>OEM label requirement, model name, logo, and packaging information.<\/li>\r\n      <\/ul>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"mistakes\">\r\n    <h2><span class=\"ez-toc-section\" id=\"common-mistakes-when-choosing-spd-uc\"><\/span>Common Mistakes When Choosing SPD Uc<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <h3>Mistake 1: Thinking higher Uc is always safer<\/h3>\r\n    <p>A higher Uc gives more continuous voltage tolerance. But it does not always mean better protection. If Uc is much higher than necessary, the voltage protection level may not be as close as the protected equipment needs.<\/p>\r\n\r\n    <h3>Mistake 2: Choosing the lowest Uc without checking grid fluctuation<\/h3>\r\n    <p>A lower Uc may look attractive because it can be linked with a lower protection level. But if the real grid voltage often rises above normal, the SPD may be stressed during daily operation and age faster.<\/p>\r\n\r\n    <h3>Mistake 3: Ignoring the earthing system<\/h3>\r\n    <p>The same nominal voltage can require different SPD structures in TN-S, TN-C-S, TT, or IT systems. Always confirm the earthing arrangement before choosing Uc and pole configuration.<\/p>\r\n\r\n    <h3>Mistake 4: Treating Uc and MCOV labels as interchangeable for OEM orders<\/h3>\r\n    <p>Uc and MCOV serve a similar selection role, but the label should match the target market and product documentation. For private label SPD orders, confirm the correct term before printing the product label or datasheet.<\/p>\r\n\r\n    <h3>Mistake 5: Using AC Uc logic for DC or solar PV SPD<\/h3>\r\n    <p>This article is for AC SPD selection. Solar PV and DC systems use Ucpv selection logic. Do not choose a PV SPD by copying 275V, 320V, 385V, or 440V AC SPD values.<\/p>\r\n\r\n    <h3>Mistake 6: Looking only at Imax<\/h3>\r\n    <p>Imax is important, but it does not answer the voltage compatibility question. A good SPD selection should consider Uc, Up, In, Imax, Type 1 or Type 2 classification, wiring mode, and backup protection.<\/p>\r\n\r\n    <div class=\"cn-cta\">\r\n      <div class=\"cn-cta-title\">Send us your panel requirement<\/div>\r\n      <p>\r\n        If you are not sure whether your order should use 275V, 320V, 385V, or 440V SPD,\r\n        send us your system voltage, earthing system, pole structure, and target market.\r\n      <\/p>\r\n      <a class=\"cn-btn leeyee-site-popup-btn\" href=\"javascript:void(0);\"><span>Send Your Panel Requirement<\/span><\/a>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"faq\">\r\n    <h2><span class=\"ez-toc-section\" id=\"faq-spd-uc-selection\"><\/span>FAQ: SPD Uc Selection<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <div class=\"cn-faq\">\r\n      <details open>\r\n        <summary>Is 275V SPD enough for a 230\/400V distribution board?<\/summary>\r\n        <div class=\"cn-faq-body\"><p>In many stable 230\/400V systems, 275V SPD is a common option. If the supply voltage is unstable, or if the project has temporary overvoltage risk, 320V or 385V may be considered after checking the system design and datasheet.<\/p><\/div>\r\n      <\/details>\r\n      <details>\r\n        <summary>When should I choose 320V instead of 275V SPD?<\/summary>\r\n        <div class=\"cn-faq-body\"><p>Choose 320V when the system is still a standard low-voltage AC system, but the buyer wants more continuous voltage margin than 275V. This is common for export panels or sites with moderate voltage fluctuation.<\/p><\/div>\r\n      <\/details>\r\n      <details>\r\n        <summary>Is 385V SPD safer than 275V SPD?<\/summary>\r\n        <div class=\"cn-faq-body\"><p>Not always. A 385V SPD can tolerate higher continuous voltage, but the protection level may be different. The correct choice depends on real grid voltage, earthing system, and protected equipment sensitivity.<\/p><\/div>\r\n      <\/details>\r\n      <details>\r\n        <summary>Can I use 440V SPD for all AC panels?<\/summary>\r\n        <div class=\"cn-faq-body\"><p>No. 440V SPD is not a universal replacement for 275V, 320V, or 385V SPD. It is used for higher-voltage or special AC applications and should be selected according to the actual system condition.<\/p><\/div>\r\n      <\/details>\r\n      <details>\r\n        <summary>What is the difference between Uc and MCOV?<\/summary>\r\n        <div class=\"cn-faq-body\"><p>Uc and MCOV serve a similar selection role in SPD selection. Uc is commonly seen in IEC-style datasheets, while MCOV is often seen in UL-style documents. For OEM orders, use the term required by the target market and product documentation.<\/p><\/div>\r\n      <\/details>\r\n      <details>\r\n        <summary>Does Uc mean the same thing as Imax?<\/summary>\r\n        <div class=\"cn-faq-body\"><p>No. Uc is the maximum continuous operating voltage. Imax is the maximum discharge current rating under a specified surge waveform. Uc tells you voltage compatibility; Imax tells you surge current capacity.<\/p><\/div>\r\n      <\/details>\r\n      <details>\r\n        <summary>Should OEM buyers confirm Uc before making private label SPD?<\/summary>\r\n        <div class=\"cn-faq-body\"><p>Yes. For OEM orders, Uc affects the label, datasheet, model number, packaging, and technical support. It should be confirmed before production, especially for export markets.<\/p><\/div>\r\n      <\/details>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section class=\"cn-related cn-uc-cluster\">\r\n    <h2><span class=\"ez-toc-section\" id=\"related-spd-uc-mcov-guides\"><\/span>Related SPD Uc \/ MCOV Guides<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      This article is part of our SPD Uc and MCOV guide series.\r\n      Use the guides below to compare cross-market terminology, calculation logic, OEM documentation, common rating values, and country-related power system differences.\r\n    <\/p>\r\n\r\n    <ul>\r\n      <li>\r\n        <a href=\"https:\/\/www.cnspd.com\/spd-uc-mcov-selection-across-markets\/\" target=\"_blank\" rel=\"noopener\">\r\n          SPD Uc and MCOV Selection Across IEC, UL and Export Markets\r\n        <\/a>\r\n        <br>\r\n        <span>\r\n          A full overview of why Uc and MCOV ratings vary across IEC-style, UL-style, GB\/T-style and export markets.\r\n        <\/span>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.cnspd.com\/spd-uc-calculation-tn-tt-it\/\" target=\"_blank\" rel=\"noopener\">\r\n          SPD Uc Calculation for TN, TT, IT and Split-Phase Systems\r\n        <\/a>\r\n        <br>\r\n        <span>\r\n          A calculation-focused guide for checking SPD Uc against earthing systems, protection modes and system voltage.\r\n        <\/span>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.cnspd.com\/spd-uc-vs-mcov-oem-labels\/\" target=\"_blank\" rel=\"noopener\">\r\n          SPD Uc vs MCOV: Difference for OEM Labels and Datasheets\r\n        <\/a>\r\n        <br>\r\n        <span>\r\n          A guide for OEM buyers who need to align Uc, MCOV, product labels, datasheets, packaging and test files.\r\n        <\/span>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.cnspd.com\/common-spd-uc-mcov-ratings\/\" target=\"_blank\" rel=\"noopener\">\r\n          Common SPD Uc and MCOV Ratings: 150V, 275V, 320V, 385V, 440V and 480V\r\n        <\/a>\r\n        <br>\r\n        <span>\r\n          A catalogue-style explanation of common Uc and MCOV rating values and where buyers often see them.\r\n        <\/span>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.cnspd.com\/spd-uc-mcov-ratings-by-country\/\" target=\"_blank\" rel=\"noopener\">\r\n          Why SPD Uc and MCOV Ratings Vary by Country and Power System\r\n        <\/a>\r\n        <br>\r\n        <span>\r\n          A market-focused guide explaining why common SPD voltage ratings differ between regions, grid systems and project requirements.\r\n        <\/span>\r\n      <\/li>\r\n    <\/ul>\r\n  <\/section>\r\n\r\n<\/article>\r\n\r\n<script>\r\n  document.addEventListener('DOMContentLoaded', function () {\r\n    document.querySelectorAll('.leeyee-site-popup-btn').forEach(function (btn) {\r\n      btn.addEventListener('click', function (e) {\r\n        e.preventDefault();\r\n        var trigger = document.querySelector('.w-popup.ush_popup_1 .w-popup-trigger');\r\n        if (trigger) {\r\n          trigger.click();\r\n        } else {\r\n          window.open('https:\/\/www.cnspd.com\/contact\/', '_blank');\r\n        }\r\n      });\r\n    });\r\n  });\r\n<\/script>\r\n\r\n<script type=\"application\/ld+json\">\r\n{\r\n  \"@context\": \"https:\/\/schema.org\",\r\n  \"@graph\": [\r\n    {\r\n      \"@type\": \"Article\",\r\n      \"headline\": \"SPD Uc Selection Guide for Distribution Boards and OEM Orders\",\r\n      \"description\": \"Choose the right AC SPD Uc for distribution boards and OEM orders. 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For distribution boards For OEM orders For panel builders Reading time: 7\u20139 minutes Quick answer: For stable 230\/400V&#8230;<\/p>","protected":false},"author":18,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1,488,422],"tags":[],"class_list":["post-29628","post","type-post","status-publish","format-standard","hentry","category-news","category-surge-protection","category-industry-news"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.9 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>SPD Uc Selection Guide: 275V, 320V, 385V or 440V?<\/title>\n<meta name=\"description\" content=\"Choose the right SPD Uc for distribution boards and OEM orders. 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Compare 275V, 320V, 385V and 440V AC SPD options by system voltage, grid condition and application.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.cnspd.com\/fr\/spd-uc-selection-guide\/\" \/>\n<meta property=\"og:site_name\" content=\"Surge Protector, Surge Arrestor, Isolating Switch - LEEYEE\" \/>\n<meta property=\"article:published_time\" content=\"2026-06-30T05:21:18+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2026-07-01T03:07:53+00:00\" \/>\n<meta name=\"author\" content=\"Devin Ling\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u00c9crit par\" \/>\n\t<meta name=\"twitter:data1\" content=\"Devin Ling\" \/>\n\t<meta name=\"twitter:label2\" content=\"Dur\u00e9e de lecture estim\u00e9e\" \/>\n\t<meta name=\"twitter:data2\" content=\"11 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/www.cnspd.com\\\/spd-uc-selection-guide\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.cnspd.com\\\/spd-uc-selection-guide\\\/\"},\"author\":{\"name\":\"Devin Ling\",\"@id\":\"https:\\\/\\\/www.cnspd.com\\\/#\\\/schema\\\/person\\\/f49dbafe62c5b47100ad2d9f88af92d3\"},\"headline\":\"SPD Uc Selection Guide for Distribution Boards and OEM Orders\",\"datePublished\":\"2026-06-30T05:21:18+00:00\",\"dateModified\":\"2026-07-01T03:07:53+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/www.cnspd.com\\\/spd-uc-selection-guide\\\/\"},\"wordCount\":2380,\"articleSection\":[\"News\",\"Surge Protection\",\"Technical Guides\"],\"inLanguage\":\"fr-FR\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.cnspd.com\\\/spd-uc-selection-guide\\\/\",\"url\":\"https:\\\/\\\/www.cnspd.com\\\/spd-uc-selection-guide\\\/\",\"name\":\"SPD Uc Selection Guide: 275V, 320V, 385V or 440V?\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.cnspd.com\\\/#website\"},\"datePublished\":\"2026-06-30T05:21:18+00:00\",\"dateModified\":\"2026-07-01T03:07:53+00:00\",\"author\":{\"@id\":\"https:\\\/\\\/www.cnspd.com\\\/#\\\/schema\\\/person\\\/f49dbafe62c5b47100ad2d9f88af92d3\"},\"description\":\"Choose the right SPD Uc for distribution boards and OEM orders. 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