{"id":30003,"date":"2026-07-13T13:43:35","date_gmt":"2026-07-13T05:43:35","guid":{"rendered":"https:\/\/www.cnspd.com\/?p=30003"},"modified":"2026-07-13T13:43:35","modified_gmt":"2026-07-13T05:43:35","slug":"vfd-surge-protection-guide-where-to-install-an-spd-in-a-variable-frequency-drive-panel","status":"publish","type":"post","link":"https:\/\/www.cnspd.com\/de\/vfd-surge-protection\/","title":{"rendered":"VFD Surge Protection Guide: Where to Install an SPD in a Variable Frequency Drive Panel"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"30003\" class=\"elementor elementor-30003\" data-elementor-post-type=\"post\">\n\t\t\t\t<div class=\"elementor-element elementor-element-7ed0475 e-flex e-con-boxed e-con e-parent\" data-id=\"7ed0475\" 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-2144024 elementor-widget elementor-widget-html\" data-id=\"2144024\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"html.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<style>\r\n  .ly-vfd-guide,\r\n  .ly-vfd-guide * {\r\n    box-sizing: border-box;\r\n  }\r\n\r\n  .ly-vfd-guide {\r\n    --ly-blue: #004898;\r\n    --ly-blue-dark: #00356f;\r\n    --ly-blue-soft: #eef6ff;\r\n    --ly-blue-pale: #f7fbff;\r\n    --ly-text: #263343;\r\n    --ly-heading: #142235;\r\n    --ly-muted: #5f6d7c;\r\n    --ly-border: #dce6f0;\r\n    --ly-warning: #914900;\r\n    --ly-warning-bg: #fff8ec;\r\n    --ly-warning-border: #efc684;\r\n    width: 100%;\r\n    max-width: 860px;\r\n    margin: 0 auto;\r\n    padding: 8px 24px 64px;\r\n    color: var(--ly-text);\r\n    font-family: inherit;\r\n    font-size: 17px;\r\n    line-height: 1.72;\r\n    overflow-wrap: anywhere;\r\n  }\r\n\r\n  .ly-vfd-guide p {\r\n    margin: 0 0 18px;\r\n  }\r\n\r\n  .ly-vfd-guide a {\r\n    color: var(--ly-blue);\r\n    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rgba(17, 58, 100, 0.06);\r\n  }\r\n\r\n  .ly-vfd-box-label {\r\n    margin: 0 0 10px !important;\r\n    color: var(--ly-blue);\r\n    font-size: 14px;\r\n    font-weight: 800;\r\n    line-height: 1.2;\r\n    letter-spacing: 0.05em;\r\n    text-transform: uppercase;\r\n  }\r\n\r\n  .ly-vfd-quick-answer p:last-child,\r\n  .ly-vfd-warning p:last-child,\r\n  .ly-vfd-note p:last-child,\r\n  .ly-vfd-cta p:last-child,\r\n  .ly-vfd-scope p:last-child {\r\n    margin-bottom: 0;\r\n  }\r\n\r\n  .ly-vfd-key-points {\r\n    display: grid;\r\n    grid-template-columns: repeat(3, minmax(0, 1fr));\r\n    gap: 14px;\r\n    margin: 24px 0 34px;\r\n  }\r\n\r\n  .ly-vfd-key-point {\r\n    min-width: 0;\r\n    padding: 18px;\r\n    border: 1px solid var(--ly-border);\r\n    border-radius: 10px;\r\n    background: #fff;\r\n  }\r\n\r\n  .ly-vfd-key-point strong {\r\n    display: block;\r\n    margin-bottom: 7px;\r\n    color: var(--ly-blue);\r\n    font-size: 16px;\r\n    line-height: 1.35;\r\n  }\r\n\r\n  .ly-vfd-key-point span {\r\n    display: block;\r\n    color: var(--ly-muted);\r\n    font-size: 14px;\r\n    line-height: 1.55;\r\n  }\r\n\r\n  .ly-vfd-toc {\r\n    margin: 30px 0 40px;\r\n    padding: 22px 24px;\r\n    border: 1px solid var(--ly-border);\r\n    border-radius: 10px;\r\n    background: #fff;\r\n  }\r\n\r\n  .ly-vfd-toc-title {\r\n    margin: 0 0 12px !important;\r\n    color: var(--ly-heading);\r\n    font-weight: 700;\r\n  }\r\n\r\n  .ly-vfd-toc ol {\r\n    columns: 2;\r\n    column-gap: 36px;\r\n    margin: 0;\r\n    padding-left: 22px;\r\n  }\r\n\r\n  .ly-vfd-toc li {\r\n    break-inside: avoid;\r\n    margin: 7px 0;\r\n    font-size: 15px;\r\n  }\r\n\r\n  .ly-vfd-toc a {\r\n    text-decoration: none;\r\n  }\r\n\r\n  .ly-vfd-toc a:hover,\r\n  .ly-vfd-toc a:focus {\r\n    text-decoration: underline;\r\n  }\r\n\r\n  .ly-vfd-figure {\r\n    width: 100%;\r\n    margin: 28px 0 34px;\r\n  }\r\n\r\n  .ly-vfd-figure-frame {\r\n    width: 100%;\r\n    overflow: hidden;\r\n   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700;\r\n  }\r\n\r\n  .ly-vfd-scroll-note {\r\n    display: none;\r\n    margin: -17px 0 22px;\r\n    color: var(--ly-muted);\r\n    font-size: 12px;\r\n    text-align: right;\r\n  }\r\n\r\n  .ly-vfd-warning {\r\n    margin: 26px 0 32px;\r\n    padding: 24px 26px;\r\n    border: 1px solid var(--ly-warning-border);\r\n    border-left: 5px solid #d47a00;\r\n    border-radius: 10px;\r\n    background: var(--ly-warning-bg);\r\n  }\r\n\r\n  .ly-vfd-warning-title {\r\n    margin: 0 0 10px !important;\r\n    color: var(--ly-warning);\r\n    font-size: 18px;\r\n    font-weight: 800;\r\n  }\r\n\r\n  .ly-vfd-note {\r\n    margin: 24px 0 30px;\r\n    padding: 22px 24px;\r\n    border: 1px solid #c9ddf1;\r\n    border-radius: 10px;\r\n    background: var(--ly-blue-soft);\r\n  }\r\n\r\n  .ly-vfd-note-title {\r\n    margin: 0 0 8px !important;\r\n    color: var(--ly-blue-dark);\r\n    font-weight: 800;\r\n  }\r\n\r\n  .ly-vfd-checklist {\r\n    margin: 22px 0 28px;\r\n    padding: 24px 26px;\r\n    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solid var(--ly-border);\r\n    border-radius: 10px;\r\n    background: #f9fbfd;\r\n  }\r\n\r\n  .ly-vfd-scope-title {\r\n    margin: 0 0 9px !important;\r\n    color: var(--ly-heading);\r\n    font-size: 18px;\r\n    font-weight: 800;\r\n  }\r\n\r\n  .ly-vfd-divider {\r\n    height: 1px;\r\n    margin: 46px 0 0;\r\n    border: 0;\r\n    background: var(--ly-border);\r\n  }\r\n\r\n  .ly-vfd-cta {\r\n    margin: 36px 0 42px;\r\n    padding: 28px;\r\n    border: 1px solid #c8dcef;\r\n    border-radius: 12px;\r\n    background: linear-gradient(135deg, #f7fbff 0%, #edf6ff 100%);\r\n  }\r\n\r\n  .ly-vfd-cta h2 {\r\n    margin: 0 0 12px;\r\n    color: var(--ly-heading);\r\n    font-size: 27px;\r\n  }\r\n\r\n  .ly-vfd-cta-actions {\r\n    display: flex;\r\n    flex-wrap: wrap;\r\n    align-items: center;\r\n    gap: 12px;\r\n    margin-top: 20px;\r\n  }\r\n\r\n  .ly-vfd-btn {\r\n    display: inline-flex !important;\r\n    align-items: center;\r\n    justify-content: center;\r\n    min-width: 244px;\r\n    min-height: 48px;\r\n    margin: 0;\r\n    padding: 13px 20px;\r\n    border: 1px solid var(--ly-blue);\r\n    border-radius: 6px;\r\n    background: var(--ly-blue);\r\n    box-shadow: none;\r\n    color: #fff !important;\r\n    font-family: inherit;\r\n    font-size: 15px;\r\n    font-weight: 700;\r\n    line-height: 1.25 !important;\r\n    text-align: center;\r\n    text-decoration: none !important;\r\n    white-space: nowrap;\r\n    cursor: pointer;\r\n    appearance: none;\r\n    -webkit-appearance: none;\r\n    opacity: 1 !important;\r\n    visibility: visible !important;\r\n  }\r\n\r\n  .ly-vfd-btn span,\r\n  .ly-vfd-btn .w-btn-label {\r\n    display: inline-block !important;\r\n    color: #fff !important;\r\n    font: inherit !important;\r\n    line-height: 1.25 !important;\r\n    opacity: 1 !important;\r\n    visibility: visible !important;\r\n    white-space: nowrap;\r\n  }\r\n\r\n  .ly-vfd-btn:hover,\r\n  .ly-vfd-btn:focus {\r\n    border-color: var(--ly-blue-dark);\r\n    background: var(--ly-blue-dark);\r\n    color: #fff !important;\r\n  }\r\n\r\n  .ly-vfd-btn:hover span,\r\n  .ly-vfd-btn:focus span {\r\n    color: #fff !important;\r\n  }\r\n\r\n  .ly-vfd-related {\r\n    margin: 42px 0 20px;\r\n  }\r\n\r\n  .ly-vfd-related h2 {\r\n    margin-top: 0;\r\n  }\r\n\r\n  .ly-vfd-related-list {\r\n    display: grid;\r\n    grid-template-columns: repeat(2, minmax(0, 1fr));\r\n    gap: 12px;\r\n    margin: 0;\r\n    padding: 0;\r\n    list-style: none;\r\n  }\r\n\r\n  .ly-vfd-related-list li {\r\n    margin: 0;\r\n  }\r\n\r\n  .ly-vfd-related-list a {\r\n    display: block;\r\n    height: 100%;\r\n    padding: 15px 17px;\r\n    border: 1px solid var(--ly-border);\r\n    border-radius: 8px;\r\n    background: #fff;\r\n    font-size: 15px;\r\n    font-weight: 600;\r\n    line-height: 1.45;\r\n    text-decoration: none;\r\n  }\r\n\r\n  .ly-vfd-related-list a:hover,\r\n  .ly-vfd-related-list a:focus {\r\n    border-color: #a9c7e3;\r\n    background: var(--ly-blue-pale);\r\n  }\r\n\r\n  .ly-vfd-faq {\r\n    margin-top: 42px;\r\n  }\r\n\r\n  .ly-vfd-faq details {\r\n    margin: 0 0 12px;\r\n    border: 1px solid var(--ly-border);\r\n    border-radius: 9px;\r\n    background: #fff;\r\n    overflow: hidden;\r\n  }\r\n\r\n  .ly-vfd-faq summary {\r\n    position: relative;\r\n    padding: 18px 48px 18px 19px;\r\n    color: var(--ly-heading);\r\n    font-size: 17px;\r\n    font-weight: 700;\r\n    line-height: 1.45;\r\n    cursor: pointer;\r\n    list-style: none;\r\n  }\r\n\r\n  .ly-vfd-faq summary::-webkit-details-marker {\r\n    display: none;\r\n  }\r\n\r\n  .ly-vfd-faq summary::after {\r\n    content: \"+\";\r\n    position: absolute;\r\n    top: 50%;\r\n    right: 19px;\r\n    color: var(--ly-blue);\r\n    font-size: 24px;\r\n    font-weight: 500;\r\n    line-height: 1;\r\n    transform: translateY(-50%);\r\n  }\r\n\r\n  .ly-vfd-faq details[open] summary::after {\r\n    content: \"\u2013\";\r\n  }\r\n\r\n  .ly-vfd-faq-answer {\r\n    padding: 0 19px 18px;\r\n    color: var(--ly-muted);\r\n  }\r\n\r\n  .ly-vfd-faq-answer p:last-child {\r\n    margin-bottom: 0;\r\n  }\r\n\r\n  \/* Desktop 1440 *\/\r\n  @media (max-width: 1440px) {\r\n    .ly-vfd-guide {\r\n      max-width: 850px;\r\n      padding-right: 23px;\r\n      padding-left: 23px;\r\n    }\r\n\r\n    .ly-vfd-guide h2 {\r\n      font-size: 31px;\r\n    }\r\n\r\n    .ly-vfd-figure {\r\n      margin-top: 27px;\r\n      margin-bottom: 33px;\r\n    }\r\n  }\r\n\r\n  \/* Desktop 1366 *\/\r\n  @media (max-width: 1366px) {\r\n    .ly-vfd-guide {\r\n      max-width: 840px;\r\n    }\r\n\r\n    .ly-vfd-intro {\r\n      font-size: 18.5px;\r\n    }\r\n\r\n    .ly-vfd-quick-answer {\r\n      padding: 25px 27px;\r\n    }\r\n\r\n    .ly-vfd-figure-frame {\r\n      border-radius: 11px;\r\n    }\r\n  }\r\n\r\n  \/* Desktop 1280 *\/\r\n  @media (max-width: 1280px) {\r\n    .ly-vfd-guide {\r\n      max-width: 820px;\r\n      padding-right: 22px;\r\n      padding-left: 22px;\r\n    }\r\n\r\n    .ly-vfd-guide h2 {\r\n      margin-top: 48px;\r\n      font-size: 30px;\r\n    }\r\n\r\n    .ly-vfd-key-point {\r\n      padding: 17px;\r\n    }\r\n\r\n    .ly-vfd-figure figcaption {\r\n      font-size: 13px;\r\n    }\r\n  }\r\n\r\n  \/* Tablet 1024 *\/\r\n  @media (max-width: 1024px) {\r\n    .ly-vfd-guide {\r\n      width: 100%;\r\n      max-width: 800px;\r\n      padding-right: 24px;\r\n      padding-left: 24px;\r\n    }\r\n\r\n    .ly-vfd-table {\r\n      min-width: 720px;\r\n    }\r\n\r\n    .ly-vfd-scenarios {\r\n      gap: 14px;\r\n    }\r\n\r\n    .ly-vfd-figure {\r\n      margin-top: 26px;\r\n      margin-bottom: 32px;\r\n    }\r\n  }\r\n\r\n  \/* Tablet 912 *\/\r\n  @media (max-width: 912px) {\r\n    .ly-vfd-guide {\r\n      max-width: 780px;\r\n      padding-right: 23px;\r\n      padding-left: 23px;\r\n    }\r\n\r\n    .ly-vfd-key-points {\r\n      gap: 12px;\r\n    }\r\n\r\n    .ly-vfd-checklist ul {\r\n      gap: 0 22px;\r\n    }\r\n\r\n    .ly-vfd-figure-frame {\r\n      box-shadow: 0 8px 24px rgba(20, 58, 96, 0.065);\r\n    }\r\n  }\r\n\r\n  \/* Tablet 820 *\/\r\n  @media (max-width: 820px) {\r\n    .ly-vfd-guide {\r\n      max-width: 100%;\r\n      padding-right: 22px;\r\n      padding-left: 22px;\r\n    }\r\n\r\n    .ly-vfd-guide h2 {\r\n      font-size: 29px;\r\n    }\r\n\r\n    .ly-vfd-key-points,\r\n    .ly-vfd-scenarios {\r\n      grid-template-columns: 1fr;\r\n    }\r\n\r\n    .ly-vfd-key-point,\r\n    .ly-vfd-scenario {\r\n      padding: 19px 20px;\r\n    }\r\n\r\n    .ly-vfd-table {\r\n      min-width: 700px;\r\n    }\r\n  }\r\n\r\n  \/* Tablet 768 *\/\r\n  @media (max-width: 768px) {\r\n    .ly-vfd-guide {\r\n      padding-right: 20px;\r\n      padding-left: 20px;\r\n      font-size: 16.5px;\r\n    }\r\n\r\n    .ly-vfd-guide h2 {\r\n      margin-top: 44px;\r\n      font-size: 28px;\r\n    }\r\n\r\n    .ly-vfd-guide h3 {\r\n      font-size: 22px;\r\n    }\r\n\r\n    .ly-vfd-toc ol {\r\n      columns: 1;\r\n    }\r\n\r\n    .ly-vfd-table {\r\n      min-width: 680px;\r\n    }\r\n\r\n    .ly-vfd-scroll-note {\r\n      display: block;\r\n    }\r\n\r\n    .ly-vfd-checklist ul,\r\n    .ly-vfd-related-list {\r\n      grid-template-columns: 1fr;\r\n    }\r\n\r\n    .ly-vfd-figure {\r\n      margin: 24px 0 30px;\r\n    }\r\n\r\n    .ly-vfd-figure-frame {\r\n      border-radius: 10px;\r\n    }\r\n  }\r\n\r\n  \/* Mobile 600 *\/\r\n  @media (max-width: 600px) {\r\n    .ly-vfd-guide {\r\n      padding: 4px 18px 52px;\r\n      font-size: 16px;\r\n      line-height: 1.68;\r\n    }\r\n\r\n    .ly-vfd-intro {\r\n      font-size: 18px;\r\n    }\r\n\r\n    .ly-vfd-meta {\r\n      display: grid;\r\n      grid-template-columns: 1fr;\r\n      gap: 5px;\r\n      padding: 12px 14px;\r\n    }\r\n\r\n    .ly-vfd-guide h2 {\r\n      margin-top: 40px;\r\n      font-size: 26px;\r\n    }\r\n\r\n    .ly-vfd-guide h3 {\r\n      margin-top: 28px;\r\n      font-size: 21px;\r\n    }\r\n\r\n    .ly-vfd-quick-answer,\r\n    .ly-vfd-warning,\r\n    .ly-vfd-note,\r\n    .ly-vfd-checklist,\r\n    .ly-vfd-cta,\r\n    .ly-vfd-scope {\r\n      padding: 21px;\r\n    }\r\n\r\n    .ly-vfd-table {\r\n      min-width: 640px;\r\n      font-size: 14px;\r\n    }\r\n\r\n    .ly-vfd-table th,\r\n    .ly-vfd-table td {\r\n      padding: 13px 14px;\r\n    }\r\n\r\n    .ly-vfd-cta h2 {\r\n      font-size: 24px;\r\n    }\r\n\r\n    .ly-vfd-figure {\r\n      margin: 23px 0 28px;\r\n    }\r\n\r\n    .ly-vfd-figure figcaption {\r\n      margin-top: 9px;\r\n      font-size: 12.8px;\r\n    }\r\n  }\r\n\r\n  \/* Mobile 540 *\/\r\n  @media (max-width: 540px) {\r\n    .ly-vfd-guide {\r\n      padding-right: 17px;\r\n      padding-left: 17px;\r\n    }\r\n\r\n    .ly-vfd-quick-answer {\r\n      margin-top: 25px;\r\n      border-left-width: 4px;\r\n    }\r\n\r\n    .ly-vfd-toc {\r\n      padding: 20px;\r\n    }\r\n\r\n    .ly-vfd-table {\r\n      min-width: 620px;\r\n    }\r\n\r\n    .ly-vfd-figure-frame {\r\n      border-radius: 9px;\r\n    }\r\n  }\r\n\r\n  \/* Mobile 480 *\/\r\n  @media (max-width: 480px) {\r\n    .ly-vfd-guide {\r\n      padding-right: 16px;\r\n      padding-left: 16px;\r\n    }\r\n\r\n    .ly-vfd-guide h2 {\r\n      font-size: 25px;\r\n    }\r\n\r\n    .ly-vfd-intro {\r\n      font-size: 17.5px;\r\n    }\r\n\r\n    .ly-vfd-cta-actions {\r\n      display: block;\r\n    }\r\n\r\n    .ly-vfd-btn {\r\n      width: 100%;\r\n      min-width: 0;\r\n      white-space: normal;\r\n    }\r\n\r\n    .ly-vfd-btn span,\r\n    .ly-vfd-btn .w-btn-label {\r\n      white-space: normal;\r\n    }\r\n\r\n    .ly-vfd-table {\r\n      min-width: 600px;\r\n    }\r\n\r\n    .ly-vfd-figure {\r\n      margin: 22px 0 27px;\r\n    }\r\n  }\r\n\r\n  \/* Mobile 430 *\/\r\n  @media (max-width: 430px) {\r\n    .ly-vfd-guide {\r\n      padding-right: 15px;\r\n      padding-left: 15px;\r\n    }\r\n\r\n    .ly-vfd-guide h2 {\r\n      font-size: 24px;\r\n    }\r\n\r\n    .ly-vfd-guide h3 {\r\n      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0.06);\r\n    }\r\n  }\r\n\r\n  \/* Mobile 390 *\/\r\n  @media (max-width: 390px) {\r\n    .ly-vfd-guide {\r\n      padding-right: 13px;\r\n      padding-left: 13px;\r\n    }\r\n\r\n    .ly-vfd-guide h2 {\r\n      font-size: 23px;\r\n    }\r\n\r\n    .ly-vfd-guide h3 {\r\n      font-size: 19.5px;\r\n    }\r\n\r\n    .ly-vfd-toc {\r\n      padding: 18px;\r\n    }\r\n\r\n    .ly-vfd-toc li {\r\n      font-size: 14.5px;\r\n    }\r\n\r\n    .ly-vfd-figure {\r\n      margin: 21px 0 26px;\r\n    }\r\n  }\r\n\r\n  \/* Mobile 375 *\/\r\n  @media (max-width: 375px) {\r\n    .ly-vfd-guide {\r\n      padding-right: 12px;\r\n      padding-left: 12px;\r\n    }\r\n\r\n    .ly-vfd-quick-answer,\r\n    .ly-vfd-warning,\r\n    .ly-vfd-note,\r\n    .ly-vfd-checklist,\r\n    .ly-vfd-cta,\r\n    .ly-vfd-scope {\r\n      padding: 18px;\r\n    }\r\n\r\n    .ly-vfd-table {\r\n      min-width: 560px;\r\n    }\r\n\r\n    .ly-vfd-btn {\r\n      padding-right: 14px;\r\n      padding-left: 14px;\r\n      font-size: 14.5px;\r\n    }\r\n\r\n    .ly-vfd-figure figcaption {\r\n      font-size: 12.3px;\r\n      line-height: 1.5;\r\n    }\r\n  }\r\n\r\n  \/* Mobile 360 *\/\r\n  @media (max-width: 360px) {\r\n    .ly-vfd-guide {\r\n      font-size: 15.8px;\r\n    }\r\n\r\n    .ly-vfd-guide h2 {\r\n      font-size: 22.5px;\r\n    }\r\n\r\n    .ly-vfd-kicker {\r\n      font-size: 12px;\r\n    }\r\n\r\n    .ly-vfd-faq summary {\r\n      padding-right: 40px;\r\n    }\r\n\r\n    .ly-vfd-figure-frame {\r\n      border-radius: 7px;\r\n    }\r\n  }\r\n\r\n  \/* Mobile 320 *\/\r\n  @media (max-width: 320px) {\r\n    .ly-vfd-guide {\r\n      padding-right: 11px;\r\n      padding-left: 11px;\r\n      font-size: 15.5px;\r\n    }\r\n\r\n    .ly-vfd-intro {\r\n      font-size: 16.5px;\r\n    }\r\n\r\n    .ly-vfd-guide h2 {\r\n      font-size: 21.5px;\r\n    }\r\n\r\n    .ly-vfd-guide h3 {\r\n      font-size: 19px;\r\n    }\r\n\r\n    .ly-vfd-quick-answer,\r\n    .ly-vfd-warning,\r\n    .ly-vfd-note,\r\n    .ly-vfd-checklist,\r\n    .ly-vfd-cta,\r\n    .ly-vfd-scope {\r\n      padding: 16px;\r\n    }\r\n\r\n    .ly-vfd-table {\r\n      min-width: 540px;\r\n    }\r\n\r\n    .ly-vfd-figure {\r\n      margin: 20px 0 24px;\r\n    }\r\n\r\n    .ly-vfd-figure figcaption {\r\n      font-size: 12px;\r\n    }\r\n  }\r\n<\/style>\r\n\r\n<article id=\"ly-vfd-guide\" class=\"ly-vfd-guide\">\r\n\r\n  <p class=\"ly-vfd-kicker\">Industrial Control Panel Guide<\/p>\r\n\r\n  <p class=\"ly-vfd-intro\">\r\n    <strong>VFD surge protection normally starts on the incoming power side of the\r\n    variable frequency drive, not on its PWM motor output.<\/strong>\r\n    A correctly selected Type 2 SPD can help limit lightning-induced and switching\r\n    transients entering the control panel. However, it cannot solve every voltage problem\r\n    between the VFD and the motor.\r\n  <\/p>\r\n\r\n  <p>\r\n    The key is to separate incoming transient overvoltage from the repetitive PWM,\r\n    reflected-wave and dV\/dt stress generated on the drive output. This guide explains\r\n    where an SPD normally belongs, when control and communication lines need separate\r\n    protection, and what panel builders should confirm before ordering.\r\n  <\/p>\r\n\r\n  <!-- Remove or edit the reviewer line if internal technical review has not been completed. -->\r\n  <div class=\"ly-vfd-meta\" aria-label=\"Article technical information\">\r\n    <span><strong>Technical scope:<\/strong> Low-voltage AC VFD control panels<\/span>\r\n    <span><strong>Technical review:<\/strong> LEEYEE Technical Team<\/span>\r\n    <span><strong>Last updated:<\/strong> July 2026<\/span>\r\n  <\/div>\r\n\r\n  <section class=\"ly-vfd-quick-answer\" aria-labelledby=\"ly-vfd-quick-title\">\r\n    <p id=\"ly-vfd-quick-title\" class=\"ly-vfd-box-label\">Quick Answer<\/p>\r\n\r\n    <p>\r\n      Install the main power SPD at the VFD control-panel incomer or on the incoming side\r\n      of the drive. Exposed RS485, Modbus, Ethernet, analog and remote-control lines may\r\n      require separate signal SPDs.\r\n    <\/p>\r\n\r\n    <p>\r\n      Do not connect a standard MOV-based AC SPD directly to the VFD PWM output unless the\r\n      drive manufacturer and the protection-device manufacturer explicitly approve that\r\n      application. Long motor cable and reflected-wave problems normally require\r\n      drive-approved output reactors, dV\/dt filters or sine-wave filters.\r\n    <\/p>\r\n  <\/section>\r\n\r\n  <div class=\"ly-vfd-key-points\" aria-label=\"VFD surge protection key points\">\r\n    <div class=\"ly-vfd-key-point\">\r\n      <strong>Protect the input<\/strong>\r\n      <span>Limit incoming transients before they reach the VFD electronics.<\/span>\r\n    <\/div>\r\n\r\n    <div class=\"ly-vfd-key-point\">\r\n      <strong>Protect exposed signals<\/strong>\r\n      <span>Assess external communication and control cables separately.<\/span>\r\n    <\/div>\r\n\r\n    <div class=\"ly-vfd-key-point\">\r\n      <strong>Do not confuse PWM with lightning<\/strong>\r\n      <span>Motor-side pulse stress normally requires a different engineering solution.<\/span>\r\n    <\/div>\r\n  <\/div>\r\n\r\n  <nav class=\"ly-vfd-toc\" aria-label=\"Table of contents\">\r\n    <p class=\"ly-vfd-toc-title\">In this guide<\/p>\r\n\r\n    <ol>\r\n      <li><a href=\"#does-vfd-need-spd\">Does a VFD need surge protection?<\/a><\/li>\r\n      <li><a href=\"#where-install-spd\">Where should the SPD be installed?<\/a><\/li>\r\n      <li><a href=\"#input-side\">Why protect the input side?<\/a><\/li>\r\n      <li><a href=\"#type-2-role\">What does a Type 2 SPD do?<\/a><\/li>\r\n      <li><a href=\"#surge-comparison\">Lightning, switching and PWM<\/a><\/li>\r\n      <li><a href=\"#output-side\">Can an SPD be used on the output?<\/a><\/li>\r\n      <li><a href=\"#signal-lines\">Control and communication lines<\/a><\/li>\r\n      <li><a href=\"#grounding\">Grounding and connection length<\/a><\/li>\r\n      <li><a href=\"#spd-cannot-fix\">What an SPD cannot fix<\/a><\/li>\r\n      <li><a href=\"#selection\">How to select the SPD<\/a><\/li>\r\n      <li><a href=\"#leeyee-direction\">LEEYEE protection direction<\/a><\/li>\r\n      <li><a href=\"#ordering-checklist\">Ordering checklist<\/a><\/li>\r\n      <li><a href=\"#vfd-faq\">Frequently asked questions<\/a><\/li>\r\n    <\/ol>\r\n  <\/nav>\r\n\r\n  <section id=\"does-vfd-need-spd\">\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\/de\/vfd-surge-protection\/#does-a-vfd-need-surge-protection\" >Does a VFD Need Surge Protection?<\/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\/de\/vfd-surge-protection\/#where-should-the-spd-be-installed-in-a-vfd-system\" >Where Should the SPD Be Installed in a VFD System?<\/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\/de\/vfd-surge-protection\/#why-is-the-vfd-input-side-the-primary-spd-location\" >Why Is the VFD Input Side the Primary SPD Location?<\/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\/de\/vfd-surge-protection\/#what-does-a-type-2-spd-do-in-a-vfd-control-panel\" >What Does a Type 2 SPD Do in a VFD Control Panel?<\/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\/de\/vfd-surge-protection\/#lightning-surge-switching-surge-and-vfd-pwm-stress-are-different\" >Lightning Surge, Switching Surge and VFD PWM Stress Are Different<\/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\/de\/vfd-surge-protection\/#can-an-spd-be-installed-on-the-output-side-of-a-vfd\" >Can an SPD Be Installed on the Output Side of a VFD?<\/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\/de\/vfd-surge-protection\/#do-vfd-control-and-communication-lines-need-signal-spds\" >Do VFD Control and Communication Lines Need Signal SPDs?<\/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\/de\/vfd-surge-protection\/#grounding-bonding-and-connection-length\" >Grounding, Bonding and Connection Length<\/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\/de\/vfd-surge-protection\/#what-an-spd-cannot-fix-in-a-vfd-installation\" >What an SPD Cannot Fix in a VFD Installation<\/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\/de\/vfd-surge-protection\/#how-to-select-an-spd-for-a-vfd-control-panel\" >How to Select an SPD for a VFD Control Panel<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/de\/vfd-surge-protection\/#leeyee-protection-direction-for-vfd-panels\" >LEEYEE Protection Direction for VFD Panels<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/de\/vfd-surge-protection\/#typical-vfd-panel-protection-scenarios\" >Typical VFD Panel Protection Scenarios<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/de\/vfd-surge-protection\/#information-to-confirm-before-ordering-a-vfd-panel-spd\" >Information to Confirm Before Ordering a VFD Panel SPD<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/de\/vfd-surge-protection\/#need-help-selecting-an-spd-for-a-vfd-panel\" >Need Help Selecting an SPD for a VFD Panel?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/de\/vfd-surge-protection\/#frequently-asked-questions\" >Frequently Asked Questions<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/de\/vfd-surge-protection\/#related-technical-guides\" >Related Technical Guides<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"does-a-vfd-need-surge-protection\"><\/span>Does a VFD Need Surge Protection?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      Not every VFD installation needs the same protection arrangement. The decision\r\n      depends on the power system, lightning exposure, panel location, upstream SPDs,\r\n      connected field wiring and the consequences of drive failure.\r\n    <\/p>\r\n\r\n    <p>\r\n      External surge protection is particularly relevant for outdoor pump stations,\r\n      water-treatment systems, mining equipment, industrial plants with long power\r\n      conductors, installations supplied by overhead lines and processes where a failed\r\n      drive would cause expensive downtime.\r\n    <\/p>\r\n\r\n    <p>\r\n      Some VFDs include internal MOVs or other transient-withstand components. These can\r\n      improve the equipment's own surge withstand, but they are not automatically a\r\n      substitute for a properly selected panel-level SPD.\r\n    <\/p>\r\n\r\n    <div class=\"ly-vfd-note\">\r\n      <p class=\"ly-vfd-note-title\">Built-in MOVs do not answer the whole question<\/p>\r\n      <p>\r\n        Check the VFD documentation. Internal protection may support the drive's equipment\r\n        withstand rating, while an external SPD is selected for the incoming installation,\r\n        project specification, discharge current and short-circuit conditions.\r\n      <\/p>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"where-install-spd\">\r\n    <h2><span class=\"ez-toc-section\" id=\"where-should-the-spd-be-installed-in-a-vfd-system\"><\/span>Where Should the SPD Be Installed in a VFD System?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      The protection position should follow the path through which the transient can enter.\r\n      For most VFD cabinets, the first priority is the incoming power connection. External\r\n      signal and communication conductors must be assessed separately.\r\n    <\/p>\r\n\r\n    <div\r\n      class=\"ly-vfd-table-wrap\"\r\n      role=\"region\"\r\n      aria-label=\"VFD SPD installation position table\"\r\n      tabindex=\"0\"\r\n    >\r\n      <table class=\"ly-vfd-table\">\r\n        <thead>\r\n          <tr>\r\n            <th>Installation point<\/th>\r\n            <th>Main risk<\/th>\r\n            <th>Typical decision<\/th>\r\n          <\/tr>\r\n        <\/thead>\r\n\r\n        <tbody>\r\n          <tr>\r\n            <td><strong>Main distribution board<\/strong><\/td>\r\n            <td>Higher-energy surge entering the installation<\/td>\r\n            <td>Type 1 or Type 1+2 where required by the lightning-protection design<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>VFD panel incomer<\/strong><\/td>\r\n            <td>Residual lightning and upstream switching transients<\/td>\r\n            <td>Type 2 SPD coordinated with upstream protection<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>PLC or control supply<\/strong><\/td>\r\n            <td>Transient reaching low-voltage control electronics<\/td>\r\n            <td>AC or DC protection matched to the actual control voltage<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>RS485, Modbus or field I\/O<\/strong><\/td>\r\n            <td>Surge entering through external signal cables<\/td>\r\n            <td>Interface-matched signal SPD near the cable-entry boundary<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>VFD motor output<\/strong><\/td>\r\n            <td>PWM, reflected-wave and dV\/dt stress<\/td>\r\n            <td>Do not use an ordinary AC SPD by default; follow both manufacturers' instructions<\/td>\r\n          <\/tr>\r\n        <\/tbody>\r\n      <\/table>\r\n    <\/div>\r\n\r\n    <p class=\"ly-vfd-scroll-note\">Swipe horizontally to view the complete table.<\/p>\r\n\r\n    <figure class=\"ly-vfd-figure\">\r\n      <div class=\"ly-vfd-figure-frame\">\r\n        <img loading=\"lazy\"\r\n          src=\"https:\/\/www.cnspd.com\/wp-content\/uploads\/2026\/07\/vfd-control-panel-surge-protection-architecture-scaled.webp\"\r\n          alt=\"VFD control panel surge protection architecture showing a Type 2 SPD on the incoming power side and a signal SPD on RS485 or Modbus control lines\"\r\n          width=\"1600\"\r\n          height=\"900\"\r\n          loading=\"lazy\"\r\n          decoding=\"async\"\r\n        >\r\n      <\/div>\r\n\r\n      <figcaption>\r\n        <strong>VFD control-panel protection architecture:<\/strong>\r\n        the main power SPD is installed on the incoming side, while exposed communication\r\n        and control lines are assessed separately.\r\n\r\n        <span class=\"ly-vfd-image-note\">\r\n          Simplified three-phase three-wire example. The actual SPD configuration depends\r\n          on system voltage, neutral arrangement and TN, TT, IT or delta earthing system.\r\n        <\/span>\r\n      <\/figcaption>\r\n    <\/figure>\r\n  <\/section>\r\n\r\n  <section id=\"input-side\">\r\n    <h2><span class=\"ez-toc-section\" id=\"why-is-the-vfd-input-side-the-primary-spd-location\"><\/span>Why Is the VFD Input Side the Primary SPD Location?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      Lightning-induced transients, utility switching events and disturbances from other\r\n      industrial loads normally enter through the VFD supply. Installing the SPD before\r\n      the drive helps limit the transient before it reaches the input rectifier, DC bus and\r\n      control electronics.\r\n    <\/p>\r\n\r\n    <p>\r\n      In a dedicated VFD cabinet, the SPD is commonly connected at the panel incomer or near\r\n      the drive input distribution point. The exact position must still respect conductor\r\n      routing, enclosure layout, backup protection, short-circuit current and the VFD\r\n      manufacturer's installation instructions.\r\n    <\/p>\r\n\r\n    <p>\r\n      Do not choose the SPD only from the VFD kilowatt or horsepower rating. The SPD must\r\n      match the electrical system, including line-to-line voltage, line-to-neutral voltage\r\n      where present, maximum continuous operating voltage and earthing arrangement.\r\n    <\/p>\r\n\r\n    <p>\r\n      See the\r\n      <a\r\n        href=\"https:\/\/www.cnspd.com\/spd-uc-selection-guide\/\"\r\n        target=\"_blank\"\r\n        rel=\"noopener\"\r\n      >\r\n        SPD Uc Selection Guide\r\n      <\/a>\r\n      for voltage-selection principles.\r\n    <\/p>\r\n  <\/section>\r\n\r\n  <section id=\"type-2-role\">\r\n    <h2><span class=\"ez-toc-section\" id=\"what-does-a-type-2-spd-do-in-a-vfd-control-panel\"><\/span>What Does a Type 2 SPD Do in a VFD Control Panel?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      A Type 2 SPD is commonly used at a distribution or control-panel level. In a VFD\r\n      cabinet, it can help limit residual lightning surges and switching transients arriving\r\n      through the incoming supply.\r\n    <\/p>\r\n\r\n    <p>A correctly selected Type 2 SPD can help protect:<\/p>\r\n\r\n    <ul>\r\n      <li>The VFD input rectifier and DC bus.<\/li>\r\n      <li>The drive control board and auxiliary power supply.<\/li>\r\n      <li>PLCs, HMIs, relays and control power supplies connected to the same panel.<\/li>\r\n      <li>The cabinet against repeated transient stress and unplanned downtime.<\/li>\r\n    <\/ul>\r\n\r\n    <div class=\"ly-vfd-warning\">\r\n      <p class=\"ly-vfd-warning-title\">An SPD is not a voltage regulator<\/p>\r\n      <p>\r\n        It is designed to respond to short-duration transient overvoltage. It cannot hold\r\n        an unstable supply at a fixed voltage or continuously absorb a sustained abnormal\r\n        system voltage.\r\n      <\/p>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"surge-comparison\">\r\n    <h2><span class=\"ez-toc-section\" id=\"lightning-surge-switching-surge-and-vfd-pwm-stress-are-different\"><\/span>Lightning Surge, Switching Surge and VFD PWM Stress Are Different<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      The phrase \u201cvoltage spike\u201d is often used for several different electrical events.\r\n      This can lead to incorrect protection decisions because the same device cannot solve\r\n      every form of overvoltage.\r\n    <\/p>\r\n\r\n    <div\r\n      class=\"ly-vfd-table-wrap\"\r\n      role=\"region\"\r\n      aria-label=\"Comparison of VFD voltage disturbances\"\r\n      tabindex=\"0\"\r\n    >\r\n      <table class=\"ly-vfd-table\">\r\n        <thead>\r\n          <tr>\r\n            <th>Disturbance<\/th>\r\n            <th>Typical source<\/th>\r\n            <th>Can an input SPD help?<\/th>\r\n            <th>Other measures<\/th>\r\n          <\/tr>\r\n        <\/thead>\r\n\r\n        <tbody>\r\n          <tr>\r\n            <td><strong>Lightning-induced surge<\/strong><\/td>\r\n            <td>Nearby lightning or an exposed incoming conductor<\/td>\r\n            <td>Yes, as part of coordinated surge protection<\/td>\r\n            <td>Upstream Type 1 or Type 1+2 where required, bonding and short connections<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Switching transient<\/strong><\/td>\r\n            <td>Transformer, contactor, capacitor bank or large inductive load<\/td>\r\n            <td>Often yes<\/td>\r\n            <td>Source suppression and correct panel design may also be required<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Temporary overvoltage<\/strong><\/td>\r\n            <td>Supply fault, neutral problem or incorrect voltage<\/td>\r\n            <td>Not as a complete solution<\/td>\r\n            <td>Correct the fault and confirm the SPD Uc or MCOV<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>PWM output pulse<\/strong><\/td>\r\n            <td>Normal high-speed switching inside the VFD<\/td>\r\n            <td>No<\/td>\r\n            <td>Drive-approved motor, cable and output-filter design<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Reflected-wave overvoltage<\/strong><\/td>\r\n            <td>Long motor cable and impedance mismatch<\/td>\r\n            <td>No<\/td>\r\n            <td>Output reactor, dV\/dt filter or sine-wave filter<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>High-frequency EMI<\/strong><\/td>\r\n            <td>PWM switching, cable coupling and poor bonding<\/td>\r\n            <td>Not by itself<\/td>\r\n            <td>EMC cable, shield termination, routing and equipotential bonding<\/td>\r\n          <\/tr>\r\n        <\/tbody>\r\n      <\/table>\r\n    <\/div>\r\n\r\n    <p class=\"ly-vfd-scroll-note\">Swipe horizontally to view the complete table.<\/p>\r\n\r\n    <figure class=\"ly-vfd-figure\">\r\n      <div class=\"ly-vfd-figure-frame\">\r\n        <img loading=\"lazy\"\r\n          src=\"https:\/\/www.cnspd.com\/wp-content\/uploads\/2026\/07\/lightning-switching-surge-vs-vfd-pwm-comparison-scaled.webp\"\r\n          alt=\"Comparison of a lightning-induced surge, an upstream switching transient and repetitive VFD PWM reflected-wave voltage stress with their different protection methods\"\r\n          width=\"1600\"\r\n          height=\"900\"\r\n          loading=\"lazy\"\r\n          decoding=\"async\"\r\n        >\r\n      <\/div>\r\n\r\n      <figcaption>\r\n        <strong>Different causes require different protection:<\/strong>\r\n        coordinated SPDs can help limit incoming lightning and switching transients, while\r\n        repetitive PWM and reflected-wave stress require drive-approved output measures.\r\n      <\/figcaption>\r\n    <\/figure>\r\n  <\/section>\r\n\r\n  <section id=\"output-side\">\r\n    <h2><span class=\"ez-toc-section\" id=\"can-an-spd-be-installed-on-the-output-side-of-a-vfd\"><\/span>Can an SPD Be Installed on the Output Side of a VFD?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <div class=\"ly-vfd-warning\">\r\n      <p class=\"ly-vfd-warning-title\">\r\n        Do not treat the VFD output as an ordinary 50\/60 Hz AC supply\r\n      <\/p>\r\n\r\n      <p>\r\n        A VFD output is a repetitive, high-frequency PWM waveform. A conventional\r\n        MOV-based AC SPD selected for a normal distribution circuit may repeatedly conduct,\r\n        overheat, age or fail when exposed to this waveform.\r\n      <\/p>\r\n    <\/div>\r\n\r\n    <p>\r\n      A standard DIN-rail Type 2 SPD should therefore not normally be connected directly\r\n      between the VFD output phases or between the output phases and earth.\r\n    <\/p>\r\n\r\n    <p>\r\n      Specialist products may exist for particular VFD output applications, but they are\r\n      not interchangeable with ordinary AC distribution SPDs. Use an output-side protection\r\n      product only when:\r\n    <\/p>\r\n\r\n    <ul>\r\n      <li>The VFD manufacturer permits the arrangement.<\/li>\r\n      <li>The protection-device manufacturer explicitly approves PWM output use.<\/li>\r\n      <li>The repetitive waveform and voltage capability match the drive.<\/li>\r\n      <li>The installation method is documented for that exact application.<\/li>\r\n    <\/ul>\r\n\r\n    <h3>What should be used for long motor cables?<\/h3>\r\n\r\n    <p>\r\n      If the problem is motor-terminal overshoot, high dV\/dt or reflected wave caused by a\r\n      long VFD-to-motor cable, use the drive manufacturer's recommended motor-side measures.\r\n    <\/p>\r\n\r\n    <ul>\r\n      <li><strong>Output reactor:<\/strong> adds impedance and can reduce voltage-edge severity.<\/li>\r\n      <li><strong>dV\/dt filter:<\/strong> slows the PWM voltage edge and limits motor-terminal overshoot.<\/li>\r\n      <li><strong>Sine-wave filter:<\/strong> converts the output closer to a sinusoidal waveform.<\/li>\r\n      <li><strong>VFD-rated motor cable:<\/strong> supports correct shielding and high-frequency return paths.<\/li>\r\n      <li><strong>Inverter-duty motor:<\/strong> provides insulation designed for PWM-related stress.<\/li>\r\n    <\/ul>\r\n\r\n    <p>\r\n      These devices solve a different problem from an incoming Type 2 SPD. Some installations\r\n      require both input surge protection and motor-side filtering.\r\n    <\/p>\r\n  <\/section>\r\n\r\n  <section id=\"signal-lines\">\r\n    <h2><span class=\"ez-toc-section\" id=\"do-vfd-control-and-communication-lines-need-signal-spds\"><\/span>Do VFD Control and Communication Lines Need Signal SPDs?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      A power SPD at the panel incomer cannot protect a transient entering through a\r\n      separate communication or field-control conductor. Signal protection becomes more\r\n      important when cables leave the cabinet, connect outdoor equipment, run between\r\n      buildings or pass through different grounding zones.\r\n    <\/p>\r\n\r\n    <p>Interfaces that may require separate assessment include:<\/p>\r\n\r\n    <ul>\r\n      <li>RS485 and Modbus RTU.<\/li>\r\n      <li>CAN bus and industrial serial networks.<\/li>\r\n      <li>Industrial Ethernet.<\/li>\r\n      <li>0\u201310 V analog control.<\/li>\r\n      <li>4\u201320 mA current loops.<\/li>\r\n      <li>Remote start, stop, alarm and digital I\/O.<\/li>\r\n      <li>External pressure, flow, temperature and level sensors.<\/li>\r\n    <\/ul>\r\n\r\n    <p>\r\n      The signal SPD must match the working voltage, interface type, transmission rate,\r\n      wiring arrangement and acceptable insertion loss. A mains Type 2 SPD must never be\r\n      substituted for a signal-line protector.\r\n    <\/p>\r\n\r\n    <p>\r\n      See the\r\n      <a\r\n        href=\"https:\/\/www.cnspd.com\/rs485-spd-guide\/\"\r\n        target=\"_blank\"\r\n        rel=\"noopener\"\r\n      >\r\n        RS485 SPD Wiring and Selection Guide\r\n      <\/a>.\r\n    <\/p>\r\n  <\/section>\r\n\r\n  <section id=\"grounding\">\r\n    <h2><span class=\"ez-toc-section\" id=\"grounding-bonding-and-connection-length\"><\/span>Grounding, Bonding and Connection Length<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      Even a correctly selected SPD can provide poor protection if its connecting conductors\r\n      are long, looped or routed incorrectly. The voltage developed along the conductors\r\n      during a fast surge adds to the SPD's own protection level.\r\n    <\/p>\r\n\r\n    <ul>\r\n      <li>Keep the protected-conductor and SPD connections short and direct.<\/li>\r\n      <li>Keep the SPD-to-PE connection short and free from unnecessary loops.<\/li>\r\n      <li>Do not coil excess conductor length.<\/li>\r\n      <li>Use the intended panel PE or equipotential bonding bar.<\/li>\r\n      <li>Avoid long parallel routing of protected and unprotected conductors.<\/li>\r\n      <li>Separate sensitive signal wiring from VFD input and motor power cables.<\/li>\r\n      <li>Terminate motor cable shielding according to the VFD manufacturer's EMC instructions.<\/li>\r\n    <\/ul>\r\n\r\n    <div class=\"ly-vfd-note\">\r\n      <p class=\"ly-vfd-note-title\">Low Up is not enough if the wiring is poor<\/p>\r\n      <p>\r\n        The installed protection level includes the effect of the connection conductors.\r\n        Compare the SPD Up with the equipment withstand level, but also control conductor\r\n        length, routing and bonding.\r\n      <\/p>\r\n    <\/div>\r\n\r\n    <p>\r\n      See the\r\n      <a\r\n        href=\"https:\/\/www.cnspd.com\/spd-up-voltage-protection-level\/\"\r\n        target=\"_blank\"\r\n        rel=\"noopener\"\r\n      >\r\n        SPD Up Voltage Protection Level Guide\r\n      <\/a>.\r\n    <\/p>\r\n  <\/section>\r\n\r\n  <section id=\"spd-cannot-fix\">\r\n    <h2><span class=\"ez-toc-section\" id=\"what-an-spd-cannot-fix-in-a-vfd-installation\"><\/span>What an SPD Cannot Fix in a VFD Installation<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      A larger SPD is not a universal answer to every drive failure. Separate transient\r\n      damage from power-quality, thermal, installation and motor-side problems.\r\n    <\/p>\r\n\r\n    <div\r\n      class=\"ly-vfd-table-wrap\"\r\n      role=\"region\"\r\n      aria-label=\"VFD problems not solved by an SPD\"\r\n      tabindex=\"0\"\r\n    >\r\n      <table class=\"ly-vfd-table\">\r\n        <thead>\r\n          <tr>\r\n            <th>Problem<\/th>\r\n            <th>Why an SPD is not the complete solution<\/th>\r\n            <th>What to investigate<\/th>\r\n          <\/tr>\r\n        <\/thead>\r\n\r\n        <tbody>\r\n          <tr>\r\n            <td><strong>Harmonics<\/strong><\/td>\r\n            <td>An SPD does not reshape current or correct harmonic distortion<\/td>\r\n            <td>Line reactor, passive filter, active filter or low-harmonic drive<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Sustained overvoltage<\/strong><\/td>\r\n            <td>An SPD is designed for transients, not continuous abnormal voltage<\/td>\r\n            <td>Transformer, neutral, system voltage and Uc or MCOV<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Motor dV\/dt stress<\/strong><\/td>\r\n            <td>The stress is produced by repetitive PWM switching<\/td>\r\n            <td>Motor cable, lead length, output reactor or filter<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Bearing current<\/strong><\/td>\r\n            <td>It is related to common-mode voltage and high-frequency current paths<\/td>\r\n            <td>Grounding, shaft grounding, insulated bearings and filter design<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Overheating<\/strong><\/td>\r\n            <td>An SPD cannot correct blocked airflow or excessive cabinet temperature<\/td>\r\n            <td>Ventilation, derating, filters, fans and enclosure design<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Incorrect VFD parameters<\/strong><\/td>\r\n            <td>An SPD cannot correct unsuitable acceleration, motor or control settings<\/td>\r\n            <td>Drive commissioning and motor nameplate data<\/td>\r\n          <\/tr>\r\n        <\/tbody>\r\n      <\/table>\r\n    <\/div>\r\n\r\n    <p class=\"ly-vfd-scroll-note\">Swipe horizontally to view the complete table.<\/p>\r\n  <\/section>\r\n\r\n  <section id=\"selection\">\r\n    <h2><span class=\"ez-toc-section\" id=\"how-to-select-an-spd-for-a-vfd-control-panel\"><\/span>How to Select an SPD for a VFD Control Panel<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      Do not select the SPD from \u201cVFD application\u201d alone. The VFD is the protected load,\r\n      but the SPD must first match the electrical system in which the panel is installed.\r\n    <\/p>\r\n\r\n    <div\r\n      class=\"ly-vfd-table-wrap\"\r\n      role=\"region\"\r\n      aria-label=\"VFD SPD selection criteria\"\r\n      tabindex=\"0\"\r\n    >\r\n      <table class=\"ly-vfd-table\">\r\n        <thead>\r\n          <tr>\r\n            <th>Information to confirm<\/th>\r\n            <th>Why it matters<\/th>\r\n            <th>Selection consequence<\/th>\r\n          <\/tr>\r\n        <\/thead>\r\n\r\n        <tbody>\r\n          <tr>\r\n            <td><strong>Nominal input voltage<\/strong><\/td>\r\n            <td>Defines the normal voltage at the SPD location<\/td>\r\n            <td>Determines the basic Uc or MCOV range<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Maximum continuous voltage<\/strong><\/td>\r\n            <td>Industrial supplies may operate above their nominal value<\/td>\r\n            <td>Prevents Uc or MCOV from being selected too low<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Three-wire or four-wire supply<\/strong><\/td>\r\n            <td>The VFD may not use neutral, while panel controls still might<\/td>\r\n            <td>Determines pole count and protection modes<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>TN, TT, IT or delta system<\/strong><\/td>\r\n            <td>Earthing changes line-to-earth voltage and required modes<\/td>\r\n            <td>Determines whether 3P, 4P, 3+1 or another arrangement is suitable<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Lightning exposure<\/strong><\/td>\r\n            <td>Outdoor and overhead systems may face greater surge current<\/td>\r\n            <td>Influences Type 1 and Type 2 coordination<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Upstream SPD<\/strong><\/td>\r\n            <td>The panel SPD must coordinate with the service or main board<\/td>\r\n            <td>Prevents each SPD from being selected as an isolated device<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Short-circuit current<\/strong><\/td>\r\n            <td>The panel may have high available fault current<\/td>\r\n            <td>Confirms SCCR and backup fuse or breaker requirements<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Required Up or VPR<\/strong><\/td>\r\n            <td>The residual voltage must suit the protected equipment<\/td>\r\n            <td>Confirms the effective protection level<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Control interfaces<\/strong><\/td>\r\n            <td>Power and signal conductors require different protection<\/td>\r\n            <td>Identifies RS485, Ethernet, analog or digital signal SPD needs<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Required standard<\/strong><\/td>\r\n            <td>IEC and UL projects use different marking and listing systems<\/td>\r\n            <td>Determines the eligible product and documentation range<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Remote alarm requirement<\/strong><\/td>\r\n            <td>Maintenance teams may need to monitor SPD condition<\/td>\r\n            <td>Determines whether an NO\/NC remote contact is required<\/td>\r\n          <\/tr>\r\n        <\/tbody>\r\n      <\/table>\r\n    <\/div>\r\n\r\n    <p class=\"ly-vfd-scroll-note\">Swipe horizontally to view the complete table.<\/p>\r\n\r\n    <h3>400 V and 480 V VFD panels are not automatically the same<\/h3>\r\n\r\n    <p>\r\n      A 400 V IEC panel and a 480 V North American panel may require different SPD voltage\r\n      ratings, protection modes, standards and short-circuit coordination. Do not treat them\r\n      as interchangeable because both are three-phase systems.\r\n    <\/p>\r\n\r\n    <h3>Do not automatically choose the highest Uc<\/h3>\r\n\r\n    <p>\r\n      A higher Uc can improve tolerance to continuous system voltage, but it may also result\r\n      in a higher protection level. Selection must balance stable operation with the impulse\r\n      withstand of the VFD and nearby control equipment.\r\n    <\/p>\r\n  <\/section>\r\n\r\n  <section id=\"leeyee-direction\">\r\n    <h2><span class=\"ez-toc-section\" id=\"leeyee-protection-direction-for-vfd-panels\"><\/span>LEEYEE Protection Direction for VFD Panels<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      The following table is a selection direction, not a substitute for checking the\r\n      electrical system. A specific model should only be confirmed after reviewing the\r\n      voltage, earthing arrangement, backup protection, panel layout and project standard.\r\n    <\/p>\r\n\r\n    <div\r\n      class=\"ly-vfd-table-wrap\"\r\n      role=\"region\"\r\n      aria-label=\"LEEYEE protection direction for VFD panels\"\r\n      tabindex=\"0\"\r\n    >\r\n      <table class=\"ly-vfd-table\">\r\n        <thead>\r\n          <tr>\r\n            <th>Protection point<\/th>\r\n            <th>LEEYEE product direction<\/th>\r\n            <th>Buyer must confirm<\/th>\r\n          <\/tr>\r\n        <\/thead>\r\n\r\n        <tbody>\r\n          <tr>\r\n            <td><strong>VFD incoming AC power<\/strong><\/td>\r\n            <td>\r\n              AC Type 2 DIN-rail SPD\r\n              <br>\r\n              <a\r\n                class=\"ly-vfd-table-link\"\r\n                href=\"https:\/\/www.cnspd.com\/type-2-din-rail-surge-protector\/\"\r\n                target=\"_blank\"\r\n                rel=\"noopener\"\r\n              >\r\n                View Type 2 SPD direction\r\n              <\/a>\r\n            <\/td>\r\n            <td>Voltage, earthing system, poles, Uc, Up, In, Imax and backup protection<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>Higher-exposure incoming panel<\/strong><\/td>\r\n            <td>\r\n              Type 1+2 DIN-rail SPD where the project requires lightning-current capability\r\n              <br>\r\n              <a\r\n                class=\"ly-vfd-table-link\"\r\n                href=\"https:\/\/www.cnspd.com\/type-1-2-din-rail-surge-protector\/\"\r\n                target=\"_blank\"\r\n                rel=\"noopener\"\r\n              >\r\n                View Type 1+2 SPD direction\r\n              <\/a>\r\n            <\/td>\r\n            <td>External lightning protection, overhead supply, upstream SPD and required Iimp<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>RS485 or Modbus line<\/strong><\/td>\r\n            <td>\r\n              Signal SPD matched to the interface\r\n              <br>\r\n              <a\r\n                class=\"ly-vfd-table-link\"\r\n                href=\"https:\/\/www.cnspd.com\/rs485-spd-guide\/\"\r\n                target=\"_blank\"\r\n                rel=\"noopener\"\r\n              >\r\n                Check RS485 protection requirements\r\n              <\/a>\r\n            <\/td>\r\n            <td>Signal voltage, wiring, baud rate, shield, grounding and installation boundary<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>SPD status monitoring<\/strong><\/td>\r\n            <td>\r\n              Power SPD with remote alarm contact where monitoring is required\r\n              <br>\r\n              <a\r\n                class=\"ly-vfd-table-link\"\r\n                href=\"https:\/\/www.cnspd.com\/spd-remote-alarm-plc\/\"\r\n                target=\"_blank\"\r\n                rel=\"noopener\"\r\n              >\r\n                Check PLC remote-contact wiring\r\n              <\/a>\r\n            <\/td>\r\n            <td>NO\/NC logic, PLC digital-input voltage and fail-safe alarm strategy<\/td>\r\n          <\/tr>\r\n\r\n          <tr>\r\n            <td><strong>VFD motor output<\/strong><\/td>\r\n            <td>No standard AC SPD recommendation<\/td>\r\n            <td>Drive manufacturer approval, PWM compatibility, motor cable length and output-filter requirement<\/td>\r\n          <\/tr>\r\n        <\/tbody>\r\n      <\/table>\r\n    <\/div>\r\n\r\n    <p class=\"ly-vfd-scroll-note\">Swipe horizontally to view the complete table.<\/p>\r\n\r\n    <div class=\"ly-vfd-warning\">\r\n      <p class=\"ly-vfd-warning-title\">Do not select from the VFD power rating alone<\/p>\r\n      <p>\r\n        A 30 kW and a 75 kW VFD connected to the same electrical system may use the same\r\n        incoming SPD configuration. The system voltage, earthing, fault current and required\r\n        protection level are normally more important than the motor power rating.\r\n      <\/p>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section>\r\n    <h2><span class=\"ez-toc-section\" id=\"typical-vfd-panel-protection-scenarios\"><\/span>Typical VFD Panel Protection Scenarios<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <div class=\"ly-vfd-scenarios\">\r\n      <div class=\"ly-vfd-scenario\">\r\n        <h3>Indoor 400 V Cabinet<\/h3>\r\n        <p>\r\n          A Type 2 SPD at the cabinet incomer may be suitable when coordinated with the\r\n          upstream board. Confirm TN or TT arrangement and whether neutral is used.\r\n        <\/p>\r\n      <\/div>\r\n\r\n      <div class=\"ly-vfd-scenario\">\r\n        <h3>Outdoor Pump Station<\/h3>\r\n        <p>\r\n          Assess upstream Type 1 or Type 1+2 protection, local Type 2 protection, remote\r\n          sensor lines, communication lines and cabinet bonding.\r\n        <\/p>\r\n      <\/div>\r\n\r\n      <div class=\"ly-vfd-scenario\">\r\n        <h3>480 V Three-Wire MCC<\/h3>\r\n        <p>\r\n          Select protection for the actual three-wire and grounding arrangement. Do not\r\n          specify a four-pole SPD simply because the system is three-phase.\r\n        <\/p>\r\n      <\/div>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"ordering-checklist\">\r\n    <h2><span class=\"ez-toc-section\" id=\"information-to-confirm-before-ordering-a-vfd-panel-spd\"><\/span>Information to Confirm Before Ordering a VFD Panel SPD<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <p>\r\n      Providing the following information allows the supplier to recommend a suitable\r\n      configuration instead of guessing from a cabinet photograph or VFD power rating.\r\n    <\/p>\r\n\r\n    <div class=\"ly-vfd-checklist\">\r\n      <ul>\r\n        <li>VFD input voltage and operating range.<\/li>\r\n        <li>System frequency.<\/li>\r\n        <li>Three-wire or four-wire supply.<\/li>\r\n        <li>TN-S, TN-C-S, TT, IT or delta system.<\/li>\r\n        <li>External lightning protection system.<\/li>\r\n        <li>Overhead or underground incoming supply.<\/li>\r\n        <li>Upstream SPD type and installation point.<\/li>\r\n        <li>Prospective short-circuit current.<\/li>\r\n        <li>Available backup fuse or breaker.<\/li>\r\n        <li>Required Type 1, Type 2 or Type 1+2 classification.<\/li>\r\n        <li>Required Uc, Up, In, Imax or Iimp.<\/li>\r\n        <li>Available DIN-rail space.<\/li>\r\n        <li>RS485, Ethernet, analog or field-I\/O interfaces.<\/li>\r\n        <li>Remote alarm contact requirement.<\/li>\r\n        <li>IEC, CE, T\u00dcV, UL or project documentation.<\/li>\r\n        <li>Quantity, labeling, packaging and OEM requirements.<\/li>\r\n      <\/ul>\r\n    <\/div>\r\n\r\n    <figure class=\"ly-vfd-figure\">\r\n      <div class=\"ly-vfd-figure-frame\">\r\n        <img loading=\"lazy\"\r\n          src=\"https:\/\/www.cnspd.com\/wp-content\/uploads\/2026\/07\/vfd-panel-spd-selection-ordering-checklist-scaled.webp\"\r\n          alt=\"VFD panel SPD selection and ordering checklist covering system voltage wiring arrangement grounding system SPD type signal lines panel layout certification and OEM requirements\"\r\n          width=\"1600\"\r\n          height=\"900\"\r\n          loading=\"lazy\"\r\n          decoding=\"async\"\r\n        >\r\n      <\/div>\r\n\r\n      <figcaption>\r\n        <strong>VFD panel SPD ordering checklist:<\/strong>\r\n        confirm the electrical system, grounding arrangement, upstream protection,\r\n        communication interfaces, cabinet layout and documentation before selecting a model.\r\n      <\/figcaption>\r\n    <\/figure>\r\n\r\n    <section class=\"ly-vfd-cta\" aria-labelledby=\"ly-vfd-cta-title\">\r\n      <h2 id=\"ly-vfd-cta-title\"><span class=\"ez-toc-section\" id=\"need-help-selecting-an-spd-for-a-vfd-panel\"><\/span>Need Help Selecting an SPD for a VFD Panel?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n      <p>\r\n        Send us the VFD input voltage, wiring arrangement, grounding system, upstream\r\n        protection, panel layout and required standard. LEEYEE can help confirm the\r\n        incoming power SPD direction and identify whether separate signal protection\r\n        should be considered.\r\n      <\/p>\r\n\r\n      <div class=\"ly-vfd-cta-actions\">\r\n        <button\r\n          type=\"button\"\r\n          class=\"ly-vfd-btn leeyee-site-popup-btn\"\r\n          aria-label=\"Request VFD SPD Selection Help\"\r\n        >\r\n          <span class=\"w-btn-label\">Request VFD SPD Selection Help<\/span>\r\n        <\/button>\r\n      <\/div>\r\n    <\/section>\r\n  <\/section>\r\n\r\n  <section id=\"vfd-faq\" class=\"ly-vfd-faq\">\r\n    <h2><span class=\"ez-toc-section\" id=\"frequently-asked-questions\"><\/span>Frequently Asked Questions<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <details>\r\n      <summary>Does every VFD need an external SPD?<\/summary>\r\n      <div class=\"ly-vfd-faq-answer\">\r\n        <p>\r\n          Not every installation needs the same arrangement. The decision depends on\r\n          lightning exposure, incoming supply, upstream protection, field wiring, project\r\n          requirements and the VFD manufacturer's built-in protection.\r\n        <\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Should the SPD be installed before or after the VFD?<\/summary>\r\n      <div class=\"ly-vfd-faq-answer\">\r\n        <p>\r\n          A normal AC distribution SPD is generally installed before the VFD, at the panel\r\n          incomer or drive input. Do not place a conventional SPD on the PWM output unless\r\n          both manufacturers approve that exact application.\r\n        <\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Can a Type 2 SPD protect a VFD?<\/summary>\r\n      <div class=\"ly-vfd-faq-answer\">\r\n        <p>\r\n          A correctly selected Type 2 SPD can limit residual lightning and switching\r\n          transients entering through the power supply. It must match the voltage, earthing\r\n          system, protection modes and short-circuit conditions.\r\n        <\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Can I install a normal SPD on the VFD output?<\/summary>\r\n      <div class=\"ly-vfd-faq-answer\">\r\n        <p>\r\n          Normally no. The VFD output is a repetitive PWM waveform rather than ordinary\r\n          sinusoidal mains power. Use only an output-side solution specifically approved\r\n          for the VFD and PWM environment.\r\n        <\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Does a VFD with built-in MOVs still need an external SPD?<\/summary>\r\n      <div class=\"ly-vfd-faq-answer\">\r\n        <p>\r\n          It may. Built-in MOVs can improve equipment withstand, but they may not meet the\r\n          installation's required SPD type, discharge current, SCCR, VPR or monitoring\r\n          specification.\r\n        <\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Does an SPD protect the motor from dV\/dt?<\/summary>\r\n      <div class=\"ly-vfd-faq-answer\">\r\n        <p>\r\n          A normal input SPD does not solve motor-side dV\/dt or reflected-wave stress.\r\n          Depending on the application, the solution may be an output reactor, dV\/dt\r\n          filter, sine-wave filter, inverter-duty motor or VFD-rated cable.\r\n        <\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Should an RS485 connection to a VFD be protected?<\/summary>\r\n      <div class=\"ly-vfd-faq-answer\">\r\n        <p>\r\n          Consider an RS485 SPD when the cable leaves the cabinet, connects outdoor\r\n          equipment, runs a long distance or crosses between buildings or grounding zones.\r\n        <\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>How close should the SPD be installed to the VFD?<\/summary>\r\n      <div class=\"ly-vfd-faq-answer\">\r\n        <p>\r\n          Install it at an appropriate incoming connection point and keep the power-side\r\n          and PE conductors short and direct. Avoid long loops and parallel routing with\r\n          unprotected incoming conductors.\r\n        <\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>What SPD voltage should be used for a 400 V or 480 V VFD?<\/summary>\r\n      <div class=\"ly-vfd-faq-answer\">\r\n        <p>\r\n          It cannot be selected from nominal voltage alone. Confirm maximum continuous\r\n          voltage, line-to-line and line-to-earth voltage, neutral arrangement, earthing\r\n          system and the applicable IEC or UL requirements.\r\n        <\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Is an input reactor the same as an SPD?<\/summary>\r\n      <div class=\"ly-vfd-faq-answer\">\r\n        <p>\r\n          No. An SPD limits short-duration transient overvoltage. An input reactor adds\r\n          impedance and is used for different power-quality and drive-protection purposes.\r\n        <\/p>\r\n      <\/div>\r\n    <\/details>\r\n  <\/section>\r\n\r\n  <section class=\"ly-vfd-scope\" aria-labelledby=\"ly-vfd-scope-title\">\r\n    <p id=\"ly-vfd-scope-title\" class=\"ly-vfd-scope-title\">\r\n      Technical Notes and Scope\r\n    <\/p>\r\n\r\n    <p>\r\n      This guide applies to low-voltage AC VFD control panels and conventional DIN-rail\r\n      power and signal SPDs. It does not replace the instructions of the VFD manufacturer,\r\n      the SPD datasheet, a lightning-risk assessment or the applicable local electrical\r\n      standard.\r\n    <\/p>\r\n\r\n    <p>\r\n      A conventional AC SPD is assumed to be installed on the incoming power side. Any\r\n      product used on a VFD PWM output must be specifically designed and approved for that\r\n      environment. Final selection must be confirmed for the actual voltage, earthing\r\n      system, fault current, upstream protection and equipment withstand level.\r\n    <\/p>\r\n  <\/section>\r\n\r\n  <hr class=\"ly-vfd-divider\">\r\n\r\n  <section class=\"ly-vfd-related\" aria-labelledby=\"ly-vfd-related-title\">\r\n    <h2 id=\"ly-vfd-related-title\"><span class=\"ez-toc-section\" id=\"related-technical-guides\"><\/span>Related Technical Guides<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n    <ul class=\"ly-vfd-related-list\">\r\n      <li>\r\n        <a\r\n          href=\"https:\/\/www.cnspd.com\/spd-selection-guide\/\"\r\n          target=\"_blank\"\r\n          rel=\"noopener\"\r\n        >\r\n          SPD Selection Guide for Industrial and Distribution Applications\r\n        <\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a\r\n          href=\"https:\/\/www.cnspd.com\/spd-uc-selection-guide\/\"\r\n          target=\"_blank\"\r\n          rel=\"noopener\"\r\n        >\r\n          SPD Uc Selection Guide\r\n        <\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a\r\n          href=\"https:\/\/www.cnspd.com\/three-phase-spd-wiring-diagram\/\"\r\n          target=\"_blank\"\r\n          rel=\"noopener\"\r\n        >\r\n          Three-Phase SPD Wiring Diagram Guide\r\n        <\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a\r\n          href=\"https:\/\/www.cnspd.com\/rs485-spd-guide\/\"\r\n          target=\"_blank\"\r\n          rel=\"noopener\"\r\n        >\r\n          RS485 SPD Wiring and Selection Guide\r\n        <\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a\r\n          href=\"https:\/\/www.cnspd.com\/spd-up-voltage-protection-level\/\"\r\n          target=\"_blank\"\r\n          rel=\"noopener\"\r\n        >\r\n          SPD Up Voltage Protection Level Guide\r\n        <\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a\r\n          href=\"https:\/\/www.cnspd.com\/spd-remote-alarm-plc\/\"\r\n          target=\"_blank\"\r\n          rel=\"noopener\"\r\n        >\r\n          SPD Remote Alarm Contact to PLC Guide\r\n        <\/a>\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    var popupButtons = document.querySelectorAll('.leeyee-site-popup-btn');\r\n\r\n    popupButtons.forEach(function (button) {\r\n      if (button.dataset.leeyeePopupBound === 'true') {\r\n        return;\r\n      }\r\n\r\n      button.dataset.leeyeePopupBound = 'true';\r\n\r\n      button.addEventListener('click', function () {\r\n        var realPopupTrigger = document.querySelector(\r\n          '.w-popup.ush_popup_1 .w-popup-trigger'\r\n        );\r\n\r\n        if (realPopupTrigger) {\r\n          realPopupTrigger.click();\r\n        } else {\r\n          window.open(\r\n            'https:\/\/www.cnspd.com\/contact\/',\r\n            '_blank',\r\n            'noopener'\r\n          );\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  \"@type\": \"FAQPage\",\r\n  \"mainEntity\": [\r\n    {\r\n      \"@type\": \"Question\",\r\n      \"name\": \"Does every VFD need an external SPD?\",\r\n      \"acceptedAnswer\": {\r\n        \"@type\": \"Answer\",\r\n        \"text\": \"Not every installation needs the same arrangement. The decision depends on lightning exposure, incoming supply, upstream protection, field wiring, project requirements and the VFD manufacturer's built-in protection.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\": \"Question\",\r\n      \"name\": \"Should the SPD be installed before or after the VFD?\",\r\n      \"acceptedAnswer\": {\r\n        \"@type\": \"Answer\",\r\n        \"text\": \"A normal AC distribution SPD is generally installed before the VFD, at the panel incomer or drive input. Do not place a conventional SPD on the PWM output unless both manufacturers approve that exact application.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\": \"Question\",\r\n      \"name\": \"Can a Type 2 SPD protect a VFD?\",\r\n      \"acceptedAnswer\": {\r\n        \"@type\": \"Answer\",\r\n        \"text\": \"A correctly selected Type 2 SPD can limit residual lightning and switching transients entering through the power supply. It must match the voltage, earthing system, protection modes and short-circuit conditions.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\": \"Question\",\r\n      \"name\": \"Can I install a normal SPD on the VFD output?\",\r\n      \"acceptedAnswer\": {\r\n        \"@type\": \"Answer\",\r\n        \"text\": \"Normally no. The VFD output is a repetitive PWM waveform rather than ordinary sinusoidal mains power. Use only an output-side solution specifically approved for the VFD and PWM environment.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\": \"Question\",\r\n      \"name\": \"Does a VFD with built-in MOVs still need an external SPD?\",\r\n      \"acceptedAnswer\": {\r\n        \"@type\": \"Answer\",\r\n        \"text\": \"It may. Built-in MOVs can improve equipment withstand, but they may not meet the installation's required SPD type, discharge current, SCCR, VPR or monitoring specification.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\": \"Question\",\r\n      \"name\": \"Does an SPD protect the motor from dV\/dt?\",\r\n      \"acceptedAnswer\": {\r\n        \"@type\": \"Answer\",\r\n        \"text\": \"A normal input SPD does not solve motor-side dV\/dt or reflected-wave stress. Depending on the application, the solution may be an output reactor, dV\/dt filter, sine-wave filter, inverter-duty motor or VFD-rated cable.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\": \"Question\",\r\n      \"name\": \"Should an RS485 connection to a VFD be protected?\",\r\n      \"acceptedAnswer\": {\r\n        \"@type\": \"Answer\",\r\n        \"text\": \"Consider an RS485 SPD when the cable leaves the cabinet, connects outdoor equipment, runs a long distance or crosses between buildings or grounding zones.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\": \"Question\",\r\n      \"name\": \"How close should the SPD be installed to the VFD?\",\r\n      \"acceptedAnswer\": {\r\n        \"@type\": \"Answer\",\r\n        \"text\": \"Install it at an appropriate incoming connection point and keep the power-side and PE conductors short and direct. Avoid long loops and parallel routing with unprotected incoming conductors.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\": \"Question\",\r\n      \"name\": \"What SPD voltage should be used for a 400 V or 480 V VFD?\",\r\n      \"acceptedAnswer\": {\r\n        \"@type\": \"Answer\",\r\n        \"text\": \"It cannot be selected from nominal voltage alone. Confirm maximum continuous voltage, line-to-line and line-to-earth voltage, neutral arrangement, earthing system and the applicable IEC or UL requirements.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\": \"Question\",\r\n      \"name\": \"Is an input reactor the same as an SPD?\",\r\n      \"acceptedAnswer\": {\r\n        \"@type\": \"Answer\",\r\n        \"text\": \"No. An SPD limits short-duration transient overvoltage. An input reactor adds impedance and is used for different power-quality and drive-protection purposes.\"\r\n      }\r\n    }\r\n  ]\r\n}\r\n<\/script>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Industrial Control Panel Guide VFD surge protection normally starts on the incoming power side of the variable frequency drive, not on its PWM motor output. A correctly selected Type 2 SPD can help limit lightning-induced and switching transients entering the control panel. However, it cannot solve every voltage problem between the VFD and the motor&#8230;.<\/p>","protected":false},"author":18,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-30003","post","type-post","status-publish","format-standard","hentry","category-news"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.9 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>VFD Surge Protection: Input vs Output SPD Guide | LEEYEE<\/title>\n<meta name=\"description\" content=\"Learn where to install an SPD in a VFD panel, why standard SPDs should not be used on PWM outputs, and how to protect power and control lines.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.cnspd.com\/de\/vfd-surge-protection\/\" \/>\n<meta property=\"og:locale\" content=\"de_DE\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"VFD Surge Protection: Input vs Output SPD Guide | LEEYEE\" \/>\n<meta property=\"og:description\" content=\"Learn where to install an SPD in a VFD panel, why standard SPDs should not be used on PWM outputs, and how to protect power and control lines.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.cnspd.com\/de\/vfd-surge-protection\/\" \/>\n<meta property=\"og:site_name\" content=\"Surge Protector, Surge Arrestor, Isolating Switch - 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