{"id":29476,"date":"2026-06-22T10:41:19","date_gmt":"2026-06-22T02:41:19","guid":{"rendered":"https:\/\/www.cnspd.com\/?p=29476"},"modified":"2026-06-22T13:29:55","modified_gmt":"2026-06-22T05:29:55","slug":"what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose","status":"publish","type":"post","link":"https:\/\/www.cnspd.com\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/","title":{"rendered":"What Is an Automatic Transfer Switch? How ATS Works &#038; How to Choose"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"29476\" class=\"elementor elementor-29476\" data-elementor-post-type=\"post\">\n\t\t\t\t<div class=\"elementor-element elementor-element-4e47fc5 e-flex e-con-boxed e-con e-parent\" data-id=\"4e47fc5\" 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-e99a507 elementor-widget elementor-widget-html\" data-id=\"e99a507\" 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  .ats-article {\r\n    max-width: 1120px;\r\n    margin: 0 auto;\r\n    color: #1f2933;\r\n    font-size: 16px;\r\n    line-height: 1.72;\r\n  }\r\n\r\n  .ats-article h1,\r\n  .ats-article h2,\r\n  .ats-article h3 {\r\n    color: #0f2742;\r\n    line-height: 1.3;\r\n    margin-top: 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}\r\n\r\n    .lyd11-desc {\r\n      font-size: 15px !important;\r\n      line-height: 1.55 !important;\r\n    }\r\n\r\n    .lyd11-specs {\r\n      gap: 7px !important;\r\n      margin-bottom: 16px !important;\r\n    }\r\n\r\n    .lyd11-spec {\r\n      font-size: 12.5px !important;\r\n      padding: 6px 10px !important;\r\n      white-space: normal !important;\r\n    }\r\n\r\n    .lyd11-actions {\r\n      width: 100% !important;\r\n      display: flex !important;\r\n      flex-direction: column !important;\r\n      gap: 10px !important;\r\n    }\r\n\r\n    .lyd11-btn-primary,\r\n    .lyd11-btn-secondary {\r\n      width: 100% !important;\r\n      text-align: center !important;\r\n      box-sizing: border-box !important;\r\n      border-radius: 10px !important;\r\n    }\r\n  }\r\n\r\n  @media (max-width: 390px) {\r\n    .ats-article {\r\n      padding: 0 12px !important;\r\n    }\r\n\r\n    .ats-article h1 {\r\n      font-size: 28px !important;\r\n    }\r\n  }\r\n<\/style>\r\n\r\n<div class=\"ats-article\">\r\n\r\n  <figure class=\"ats-figure\">\r\n    <img decoding=\"async\" class=\"ats-hero-img\" src=\"https:\/\/www.cnspd.com\/wp-content\/uploads\/2026\/06\/Automatic-transfer-switch.png\" alt=\"What is an automatic transfer switch guide with 2P and 4P ATS for backup power systems\">\r\n  <\/figure>\r\n\r\n  <div class=\"ats-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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#quick-answer\" >Quick Answer<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#key-takeaways\" >Key Takeaways<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#what-is-an-automatic-transfer-switch\" >What Is an Automatic Transfer Switch?<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#what-does-an-ats-do\" >What Does an ATS Do?<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#how-does-an-automatic-transfer-switch-work\" >How Does an Automatic Transfer Switch Work?<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#automatic-transfer-switch-example\" >Automatic Transfer Switch Example<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#manual-transfer-switch-vs-automatic-transfer-switch\" >Manual Transfer Switch vs Automatic Transfer Switch<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#main-ats-application-types\" >Main ATS Application Types<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#open-transition-vs-closed-transition-ats\" >Open Transition vs Closed Transition ATS<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#2p-vs-4p-automatic-transfer-switch\" >2P vs 4P Automatic Transfer Switch<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#how-to-choose-the-right-automatic-transfer-switch\" >How to Choose the Right Automatic Transfer Switch<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#key-specifications-to-check-before-buying-an-ats\" >Key Specifications to Check Before Buying an ATS<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#standards-and-compliance\" >Standards and Compliance<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#ats-vs-mts-vs-ups\" >ATS vs MTS vs UPS<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#does-an-ats-provide-overload-or-short-circuit-protection\" >Does an ATS Provide Overload or Short-Circuit Protection?<\/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\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#common-automatic-transfer-switch-applications\" >Common Automatic Transfer Switch Applications<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#leeyee-ats-63-automatic-transfer-switch\" >LEEYEE ATS-63 Automatic Transfer Switch<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#when-ats-63-is-a-good-fit\" >When ATS-63 Is a Good Fit<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-19\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#when-ats-63-may-not-be-the-right-fit\" >When ATS-63 May Not Be the Right Fit<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-20\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#common-mistakes-when-choosing-an-ats\" >Common Mistakes When Choosing an ATS<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-21\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#when-should-you-use-an-automatic-transfer-switch\" >When Should You Use an Automatic Transfer Switch?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-22\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#frequently-asked-questions-about-automatic-transfer-switches\" >Frequently Asked Questions About Automatic Transfer Switches<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-23\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#need-help-choosing-an-ats\" >Need Help Choosing an ATS?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-24\" href=\"#\" data-href=\"https:\/\/www.cnspd.com\/it\/what-is-an-automatic-transfer-switch-how-ats-works-how-to-choose\/#conclusion\" >Conclusion<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"quick-answer\"><\/span>Quick Answer<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n    <p>An automatic transfer switch, or ATS, switches a load between two power sources.<\/p>\r\n    <p>When the main power fails, the ATS moves the load to backup power.<\/p>\r\n    <p>The backup source can be a generator, inverter, solar backup system, or another AC source.<\/p>\r\n    <p>When the main power comes back and becomes stable, the ATS switches the load back.<\/p>\r\n    <p>For LEEYEE ATS-63, the transfer switching time is less than 50 ms.<\/p>\r\n    <p>This is the ATS switching time only. A generator may still need extra time to start and stabilize.<\/p>\r\n  <\/div>\r\n\r\n  <div class=\"ats-key-box\">\r\n    <h2><span class=\"ez-toc-section\" id=\"key-takeaways\"><\/span>Key Takeaways<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n    <ul>\r\n      <li>An ATS switches a load between normal power and backup power.<\/li>\r\n      <li>A 2P ATS is commonly used for single-phase systems.<\/li>\r\n      <li>A 4P ATS is commonly used for three-phase systems.<\/li>\r\n      <li>Choose the ATS by current, voltage, pole number, and backup source.<\/li>\r\n      <li>An ATS is not a UPS. It does not store energy.<\/li>\r\n      <li>An ATS does not replace breakers, fuses, SPDs, or grounding.<\/li>\r\n      <li>LEEYEE ATS-63 is available in 2P \/ 4P and 6A\u201363A options.<\/li>\r\n    <\/ul>\r\n  <\/div>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"what-is-an-automatic-transfer-switch\"><\/span>What Is an Automatic Transfer Switch?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>An automatic transfer switch is a device for backup power systems.<\/p>\r\n  <p>It connects the load to one power source at a time. Usually, one source is normal power. The other source is backup power.<\/p>\r\n  <p>Normal power can be utility grid power. Backup power can be a generator, inverter, solar backup system, or another AC source.<\/p>\r\n  <p>The ATS watches the power sources. If normal power fails, the ATS switches the load to backup power when the backup source is ready.<\/p>\r\n  <p>The key idea is simple: an ATS is not just an on\/off switch. It is a source transfer device.<\/p>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"what-does-an-ats-do\"><\/span>What Does an ATS Do?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>An ATS keeps the load connected to the available power source.<\/p>\r\n  <p>In a simple backup system, the ATS does this:<\/p>\r\n\r\n  <ol>\r\n    <li>It monitors normal power.<\/li>\r\n    <li>It detects a power failure or unstable voltage.<\/li>\r\n    <li>It checks the backup source.<\/li>\r\n    <li>It transfers the load to backup power.<\/li>\r\n    <li>It transfers the load back when normal power returns.<\/li>\r\n  <\/ol>\r\n\r\n  <p>This reduces manual switching. It also helps keep important loads powered during an outage.<\/p>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"how-does-an-automatic-transfer-switch-work\"><\/span>How Does an Automatic Transfer Switch Work?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>An ATS monitors two power sources.<\/p>\r\n  <p>One source is the normal source. The other source is the backup source.<\/p>\r\n  <p>When normal power is available, the load stays on normal power.<\/p>\r\n  <p>When normal power fails, the ATS checks the backup source.<\/p>\r\n  <p>If the backup source is ready, the ATS transfers the load.<\/p>\r\n\r\n  <p>A typical ATS process looks like this:<\/p>\r\n\r\n  <ol>\r\n    <li>Utility power supplies the load.<\/li>\r\n    <li>Utility power fails or becomes unstable.<\/li>\r\n    <li>The ATS detects the problem.<\/li>\r\n    <li>The backup source becomes available.<\/li>\r\n    <li>The ATS transfers the load to backup power.<\/li>\r\n    <li>Utility power returns.<\/li>\r\n    <li>The ATS transfers the load back to utility power.<\/li>\r\n  <\/ol>\r\n\r\n  <figure class=\"ats-figure ats-zoom-figure\">\r\n    <a class=\"ats-img-zoom-link\" ref=\"magnificPopup\" href=\"https:\/\/www.cnspd.com\/wp-content\/uploads\/2026\/06\/How-automatic-transfer-switches-work.png\" target=\"_blank\" rel=\"noopener\" aria-label=\"Open larger ATS working process diagram\">\r\n      <img decoding=\"async\" class=\"ats-article-img\" src=\"https:\/\/www.cnspd.com\/wp-content\/uploads\/2026\/06\/How-automatic-transfer-switches-work.png\" alt=\"How a compact automatic transfer switch transfers load between utility power and generator or inverter backup source\">\r\n      <span class=\"ats-img-zoom-badge\">View larger<\/span>\r\n    <\/a>\r\n    <figcaption>How a compact automatic transfer switch transfers the load between utility power and backup power.<\/figcaption>\r\n  <\/figure>\r\n\r\n  <p>LEEYEE ATS-63 has a transfer switching time of less than 50 ms.<\/p>\r\n  <p>This does not mean the whole backup system recovers in 50 ms.<\/p>\r\n  <p>If the backup source is a generator, the generator still needs time to start and stabilize.<\/p>\r\n  <p>If the load cannot accept even a short power break, use a UPS or another power design.<\/p>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"automatic-transfer-switch-example\"><\/span>Automatic Transfer Switch Example<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>Think about a small building with utility power and a backup generator.<\/p>\r\n  <p>Under normal conditions, the building runs on utility power.<\/p>\r\n  <p>When utility power fails, the backup generator starts. When the backup source is ready, the ATS transfers the load.<\/p>\r\n  <p>When utility power returns and becomes stable, the ATS transfers the load back.<\/p>\r\n  <p>The same idea can also be used with solar inverter backup systems, distribution boards, pump panels, and small control cabinets.<\/p>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"manual-transfer-switch-vs-automatic-transfer-switch\"><\/span>Manual Transfer Switch vs Automatic Transfer Switch<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>A manual transfer switch needs a person to operate it.<\/p>\r\n  <p>An automatic transfer switch does the switching by itself.<\/p>\r\n\r\n  <div class=\"ats-table-wrap\">\r\n    <table>\r\n      <thead>\r\n        <tr>\r\n          <th>Type<\/th>\r\n          <th>How It Works<\/th>\r\n          <th>Typical Use<\/th>\r\n        <\/tr>\r\n      <\/thead>\r\n      <tbody>\r\n        <tr>\r\n          <td>Manual transfer switch<\/td>\r\n          <td>Switched by hand<\/td>\r\n          <td>Simple systems where manual switching is acceptable<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Non-automatic transfer switch<\/td>\r\n          <td>Electrically operated, but manually controlled<\/td>\r\n          <td>Systems that need powered operation but not full automation<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Automatic transfer switch<\/td>\r\n          <td>Switches automatically based on source status<\/td>\r\n          <td>Backup systems that need automatic power transfer<\/td>\r\n        <\/tr>\r\n      <\/tbody>\r\n    <\/table>\r\n  <\/div>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"main-ats-application-types\"><\/span>Main ATS Application Types<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>An ATS can be used in different source arrangements. The right choice depends on the power system.<\/p>\r\n\r\n  <div class=\"ats-accordion\">\r\n    <details>\r\n      <summary>Utility to Generator<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>This is one of the most common ATS uses.<\/p>\r\n        <p>Normal power is utility power. Backup power is a generator.<\/p>\r\n        <p>When utility power fails, the ATS transfers the load to generator power. When utility power returns, it transfers the load back.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Utility to Utility<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>In this setup, both sources are utility supplies.<\/p>\r\n        <p>If one source fails, the ATS transfers the load to the second source.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Utility to Inverter or Solar Backup<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Some solar or battery backup systems use an ATS to switch between grid power and inverter output.<\/p>\r\n        <p>Check the inverter voltage, frequency, grounding method, neutral wiring, and local code before selection.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n  <\/div>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"open-transition-vs-closed-transition-ats\"><\/span>Open Transition vs Closed Transition ATS<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>Transfer switches are often described as open transition or closed transition.<\/p>\r\n\r\n  <div class=\"ats-accordion\">\r\n    <details>\r\n      <summary>Open Transition ATS<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Open transition means break-before-make.<\/p>\r\n        <p>The ATS disconnects from one source before it connects to the other source.<\/p>\r\n        <p>This is common in general backup power systems. A short interruption may happen during transfer.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Closed Transition ATS<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Closed transition means make-before-break.<\/p>\r\n        <p>It briefly connects two synchronized sources before disconnecting from the first source.<\/p>\r\n        <p>This is a more complex system. It is usually used in larger engineered power systems.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n  <\/div>\r\n\r\n  <div class=\"ats-note\">\r\n    <h3>Important Note for Compact ATS Products<\/h3>\r\n    <p>Do not assume every ATS supports closed transition.<\/p>\r\n    <p>Compact DIN-rail ATS products are mainly used for general backup source switching.<\/p>\r\n    <p>If your project needs zero interruption or source synchronization, use a different engineered power solution.<\/p>\r\n  <\/div>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"2p-vs-4p-automatic-transfer-switch\"><\/span>2P vs 4P Automatic Transfer Switch<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>Pole number is one of the most important ATS selection points.<\/p>\r\n  <p>Do not choose only by current rating. A 63A ATS may still be wrong if the pole number does not match the wiring.<\/p>\r\n\r\n  <h3>What Is a 2P ATS?<\/h3>\r\n\r\n  <p>A 2P ATS has two switching poles.<\/p>\r\n  <p>It is commonly used for single-phase systems where Line and Neutral need to be switched.<\/p>\r\n\r\n  <p>Typical 2P ATS applications include:<\/p>\r\n\r\n  <ul>\r\n    <li>Home backup systems<\/li>\r\n    <li>Small shops<\/li>\r\n    <li>Small offices<\/li>\r\n    <li>Single-phase generator backup<\/li>\r\n    <li>Single-phase inverter backup<\/li>\r\n    <li>Residential distribution boards<\/li>\r\n  <\/ul>\r\n\r\n  <h3>What Is a 4P ATS?<\/h3>\r\n\r\n  <p>A 4P ATS has four switching poles.<\/p>\r\n  <p>It is commonly used for three-phase systems where L1, L2, L3, and Neutral need to be switched.<\/p>\r\n\r\n  <p>Typical 4P ATS applications include:<\/p>\r\n\r\n  <ul>\r\n    <li>Three-phase commercial systems<\/li>\r\n    <li>Small factories<\/li>\r\n    <li>Control cabinets<\/li>\r\n    <li>Three-phase generator backup<\/li>\r\n    <li>Pump control panels<\/li>\r\n    <li>Distribution boards that require neutral switching<\/li>\r\n  <\/ul>\r\n\r\n  <h3>2P vs 4P ATS Selection Table<\/h3>\r\n\r\n  <div class=\"ats-table-wrap\">\r\n    <table>\r\n      <thead>\r\n        <tr>\r\n          <th>System Type<\/th>\r\n          <th>Common ATS Choice<\/th>\r\n          <th>Notes<\/th>\r\n        <\/tr>\r\n      <\/thead>\r\n      <tbody>\r\n        <tr>\r\n          <td>Single-phase AC system<\/td>\r\n          <td>2P ATS<\/td>\r\n          <td>Common for homes, shops, and small offices<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Single-phase generator backup<\/td>\r\n          <td>2P ATS<\/td>\r\n          <td>Used for L + N switching<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Three-phase AC system<\/td>\r\n          <td>4P ATS<\/td>\r\n          <td>Used for L1 + L2 + L3 + N switching<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Three-phase generator backup<\/td>\r\n          <td>4P ATS<\/td>\r\n          <td>Common in control cabinets and distribution systems<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Inverter backup system<\/td>\r\n          <td>2P or 4P<\/td>\r\n          <td>Depends on inverter output and wiring design<\/td>\r\n        <\/tr>\r\n      <\/tbody>\r\n    <\/table>\r\n  <\/div>\r\n\r\n  <figure class=\"ats-figure ats-zoom-figure\">\r\n    <a class=\"ats-img-zoom-link\" ref=\"magnificPopup\" href=\"https:\/\/www.cnspd.com\/wp-content\/uploads\/2026\/06\/2P-vs-4P-ATS-comparison-guide.png\" target=\"_blank\" rel=\"noopener\" aria-label=\"Open larger 2P vs 4P ATS comparison diagram\">\r\n      <img decoding=\"async\" class=\"ats-article-img\" src=\"https:\/\/www.cnspd.com\/wp-content\/uploads\/2026\/06\/2P-vs-4P-ATS-comparison-guide.png\" alt=\"2P vs 4P ATS pole configuration for single-phase and three-phase systems\">\r\n      <span class=\"ats-img-zoom-badge\">View larger<\/span>\r\n    <\/a>\r\n    <figcaption>2P and 4P ATS pole configuration difference for single-phase and three-phase backup power systems.<\/figcaption>\r\n  <\/figure>\r\n\r\n  <p>Simple rule: use 2P for many single-phase systems. Use 4P for many three-phase systems.<\/p>\r\n  <p>Final selection should always follow the actual wiring design.<\/p>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"how-to-choose-the-right-automatic-transfer-switch\"><\/span>How to Choose the Right Automatic Transfer Switch<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>Start with the power system. Then choose the ATS.<\/p>\r\n\r\n  <h3>1. Confirm the Phase Type<\/h3>\r\n  <p>Is the system single-phase or three-phase?<\/p>\r\n  <p>Many single-phase systems use 2P. Many three-phase systems use 4P.<\/p>\r\n\r\n  <h3>2. Confirm the Load Current<\/h3>\r\n  <p>The ATS current rating must match or exceed the load current.<\/p>\r\n  <p>LEEYEE ATS-63 is available in 6A, 10A, 16A, 20A, 25A, 32A, 40A, 50A, and 63A.<\/p>\r\n  <p>For motors, pumps, and compressors, also check starting current.<\/p>\r\n\r\n  <h3>3. Confirm the System Voltage<\/h3>\r\n  <p>The ATS voltage rating must match the system voltage.<\/p>\r\n  <p>LEEYEE ATS-63 supports AC110V, AC220V, AC400V, and 50\/60Hz configurations.<\/p>\r\n\r\n  <h3>4. Confirm the Backup Source<\/h3>\r\n  <p>The backup source may be a generator, inverter, solar backup system, utility backup, or another AC source.<\/p>\r\n  <p>For inverter and solar systems, check neutral wiring, grounding, and local code.<\/p>\r\n\r\n  <h3>5. Confirm the Transfer Switching Time<\/h3>\r\n  <p>Transfer switching time tells you how fast the ATS changes from one source to another.<\/p>\r\n  <p>LEEYEE ATS-63 transfer switching time is less than 50 ms.<\/p>\r\n  <p>This is not the same as total backup recovery time. A generator may need extra time to start.<\/p>\r\n\r\n  <h3>6. Confirm Manual and Automatic Operation<\/h3>\r\n  <p>Compact ATS products often support both manual and automatic operation.<\/p>\r\n  <p>Manual operation is useful for testing and maintenance. Automatic operation is used for normal backup switching.<\/p>\r\n\r\n  <h3>7. Confirm Installation Conditions<\/h3>\r\n  <p>Check DIN-rail space, wiring space, terminal access, heat dissipation, cabinet layout, and installation environment.<\/p>\r\n\r\n  <figure class=\"ats-figure ats-zoom-figure\">\r\n    <a class=\"ats-img-zoom-link\" ref=\"magnificPopup\" href=\"https:\/\/www.cnspd.com\/wp-content\/uploads\/2026\/06\/How-to-choose-the-right-ATS.png\" target=\"_blank\" rel=\"noopener\" aria-label=\"Open larger ATS selection flowchart\">\r\n      <img decoding=\"async\" class=\"ats-article-img\" src=\"https:\/\/www.cnspd.com\/wp-content\/uploads\/2026\/06\/How-to-choose-the-right-ATS.png\" alt=\"Automatic transfer switch selection flowchart for choosing 2P or 4P ATS by phase type current voltage and backup source\">\r\n      <span class=\"ats-img-zoom-badge\">View larger<\/span>\r\n    <\/a>\r\n    <figcaption>ATS selection flowchart for choosing the right automatic transfer switch by phase type, current, voltage, and backup source.<\/figcaption>\r\n  <\/figure>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"key-specifications-to-check-before-buying-an-ats\"><\/span>Key Specifications to Check Before Buying an ATS<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <div class=\"ats-table-wrap\">\r\n    <table>\r\n      <thead>\r\n        <tr>\r\n          <th>Specification<\/th>\r\n          <th>What to Confirm<\/th>\r\n        <\/tr>\r\n      <\/thead>\r\n      <tbody>\r\n        <tr>\r\n          <td>Rated voltage<\/td>\r\n          <td>Must match the system voltage<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Rated current<\/td>\r\n          <td>Must match or exceed the load current<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Pole configuration<\/td>\r\n          <td>Choose 2P or 4P by phase type and wiring method<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Frequency<\/td>\r\n          <td>Check 50Hz or 60Hz<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Transfer switching time<\/td>\r\n          <td>LEEYEE ATS-63 transfer switching time is &lt;50 ms<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Backup source<\/td>\r\n          <td>Generator, inverter, solar backup, utility backup, or other AC source<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Protection design<\/td>\r\n          <td>Use proper breakers, fuses, SPDs, grounding, and cable sizing<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>Wiring diagram<\/td>\r\n          <td>Must match the actual system design<\/td>\r\n        <\/tr>\r\n      <\/tbody>\r\n    <\/table>\r\n  <\/div>\r\n\r\n  <p>A reliable supplier should provide technical data, dimensions, wiring diagrams, and selection support.<\/p>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"standards-and-compliance\"><\/span>Standards and Compliance<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>Buyers often ask for CE and RoHS documentation for compact ATS products.<\/p>\r\n  <p>CE relates to applicable European conformity requirements for the declared product category.<\/p>\r\n  <p>RoHS relates to restricted hazardous substances in electrical and electronic equipment.<\/p>\r\n  <p>LEEYEE automatic transfer switches can be supplied with CE and RoHS documentation.<\/p>\r\n  <p>Project requirements can vary by country. For regulated installations, confirm local standards before ordering.<\/p>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"ats-vs-mts-vs-ups\"><\/span>ATS vs MTS vs UPS<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>ATS, MTS, and UPS devices do different jobs.<\/p>\r\n\r\n  <div class=\"ats-table-wrap\">\r\n    <table>\r\n      <thead>\r\n        <tr>\r\n          <th>Device<\/th>\r\n          <th>Full Name<\/th>\r\n          <th>Main Function<\/th>\r\n        <\/tr>\r\n      <\/thead>\r\n      <tbody>\r\n        <tr>\r\n          <td>ATS<\/td>\r\n          <td>Automatic Transfer Switch<\/td>\r\n          <td>Automatically switches the load between two power sources<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>MTS<\/td>\r\n          <td>Manual Transfer Switch<\/td>\r\n          <td>Switches the load by manual operation<\/td>\r\n        <\/tr>\r\n        <tr>\r\n          <td>UPS<\/td>\r\n          <td>Uninterruptible Power Supply<\/td>\r\n          <td>Provides temporary battery power during an interruption<\/td>\r\n        <\/tr>\r\n      <\/tbody>\r\n    <\/table>\r\n  <\/div>\r\n\r\n  <p>An ATS does not store energy. It only transfers the load.<\/p>\r\n  <p>A UPS stores energy in batteries. Some systems use an ATS and a UPS together.<\/p>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"does-an-ats-provide-overload-or-short-circuit-protection\"><\/span>Does an ATS Provide Overload or Short-Circuit Protection?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>No.<\/p>\r\n  <p>An ATS transfers the load between power sources. It does not replace circuit protection devices.<\/p>\r\n  <p>A complete system should include the right breakers, fuses, surge protection, grounding, and cable sizing.<\/p>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"common-automatic-transfer-switch-applications\"><\/span>Common Automatic Transfer Switch Applications<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <div class=\"ats-accordion\">\r\n    <details>\r\n      <summary>Home Backup Power<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>An ATS can switch selected home circuits from utility power to generator or inverter backup.<\/p>\r\n        <p>Typical loads include lighting, refrigerators, routers, water pumps, and security systems.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Small Shops and Offices<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Small commercial users may need backup power for lighting, cash registers, communication devices, refrigeration, or security systems.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Generator Backup Systems<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>The ATS transfers the load to generator power when utility power fails.<\/p>\r\n        <p>It transfers the load back when utility power returns.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Solar and Inverter Backup Systems<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Some solar or battery backup systems use an ATS to switch between grid power and inverter output.<\/p>\r\n        <p>Always check inverter output, neutral wiring, grounding, load type, and local code.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Pump Control Systems<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Pumps may need backup power in irrigation, drainage, and control cabinet systems.<\/p>\r\n        <p>For pump loads, check running current and starting current.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Telecom Cabinets<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Compact ATS products can be used in telecom cabinets and remote equipment rooms.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Control Cabinets and Distribution Boards<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>An ATS can support auxiliary circuits, monitoring systems, fans, small motors, and backup circuits.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n  <\/div>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"leeyee-ats-63-automatic-transfer-switch\"><\/span>LEEYEE ATS-63 Automatic Transfer Switch<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>LEEYEE provides the ATS-63 series for compact backup power systems.<\/p>\r\n  <p>It is suitable for generator backup, solar inverter backup, small distribution systems, and control cabinets.<\/p>\r\n  <p>ATS-63 is a compact DIN-rail automatic transfer switch. It switches between power A and power B in AC systems.<\/p>\r\n  <p>It is available in 2P and 4P versions for single-phase and three-phase applications.<\/p>\r\n\r\n  <div class=\"lyd11\" style=\"margin:24px 0 32px;\">\r\n    <div class=\"lyd11-bar\"><\/div>\r\n    <div class=\"lyd11-inner\">\r\n\r\n      <img decoding=\"async\" class=\"lyd11-img\" src=\"https:\/\/www.cnspd.com\/wp-content\/uploads\/2026\/06\/2.png\" alt=\"LEEYEE ATS-63 automatic transfer switch for solar backup generator and grid power systems\" \/>\r\n\r\n      <div class=\"lyd11-body\">\r\n        <div class=\"lyd11-title-row\">\r\n          <span class=\"lyd11-title\">ATS-63 Automatic Transfer Switch for Backup Power<\/span>\r\n          <span class=\"lyd11-badge\">2P \/ 4P<\/span>\r\n        <\/div>\r\n\r\n        <div class=\"lyd11-desc\">Compact DIN-rail ATS for generator backup, solar inverter backup, grid power switching, and small distribution systems.<\/div>\r\n\r\n        <div class=\"lyd11-specs\">\r\n          <span class=\"lyd11-spec\">6A\u201363A<\/span>\r\n          <span class=\"lyd11-spec\">AC110V \/ 220V \/ 400V<\/span>\r\n          <span class=\"lyd11-spec\">&lt;50 ms transfer<\/span>\r\n          <span class=\"lyd11-spec\">DIN rail<\/span>\r\n          <span class=\"lyd11-spec\">CE \/ RoHS<\/span>\r\n        <\/div>\r\n\r\n        <div class=\"lyd11-actions\">\r\n          <a class=\"lyd11-btn-primary\" href=\"https:\/\/www.cnspd.com\/products\/leeyee-automatic-transfer-switch-solar-backup\/\" target=\"_blank\" rel=\"noopener\">View Product<\/a>\r\n          <a class=\"lyd11-btn-secondary open-contact\" href=\"javascript:void(0);\">Get Quote<\/a>\r\n        <\/div>\r\n      <\/div>\r\n\r\n    <\/div>\r\n  <\/div>\r\n\r\n  <p>For full technical data, wiring details, and dimensions, view the ATS-63 product page or contact LEEYEE for selection support.<\/p>\r\n\r\n  <div class=\"ats-product-note\">\r\n    <h2><span class=\"ez-toc-section\" id=\"when-ats-63-is-a-good-fit\"><\/span>When ATS-63 Is a Good Fit<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n    <p>ATS-63 is a good fit for compact AC backup systems.<\/p>\r\n    <p>Typical uses include home backup, generator backup, and solar inverter backup.<\/p>\r\n    <p>It can also be used in small shops, light commercial distribution, control panels, and telecom cabinets.<\/p>\r\n    <p>Use it only when the current, voltage, pole number, wiring method, and transfer requirements match the system.<\/p>\r\n  <\/div>\r\n\r\n  <div class=\"ats-note\">\r\n    <h2><span class=\"ez-toc-section\" id=\"when-ats-63-may-not-be-the-right-fit\"><\/span>When ATS-63 May Not Be the Right Fit<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n    <p>ATS-63 is not a large power transfer system.<\/p>\r\n    <p>ATS-63 is not suitable for every system.<\/p>\r\n    <p>It is not intended for systems above 63A, data centers, hospitals, zero-interruption loads, or closed transition systems.<\/p>\r\n    <p>It also does not provide overload protection by itself.<\/p>\r\n    <p>For those projects, use a larger engineered transfer solution.<\/p>\r\n  <\/div>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"common-mistakes-when-choosing-an-ats\"><\/span>Common Mistakes When Choosing an ATS<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <div class=\"ats-accordion\">\r\n    <details>\r\n      <summary>Choosing Only by Current Rating<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>\u201cI need a 63A ATS\u201d is not enough.<\/p>\r\n        <p>You also need voltage, phase type, pole number, backup source, wiring method, and transfer time.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Using 2P ATS in a Three-Phase System<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>A 2P ATS is not suitable for a standard three-phase system that needs four-pole switching.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Ignoring Neutral Switching<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Neutral switching depends on the grounding system, generator design, inverter wiring, and local code.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Undersizing the ATS<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>The ATS should not operate above its rated current.<\/p>\r\n        <p>For motors and pumps, also check starting current.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Treating ATS as a UPS<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>An ATS does not provide battery backup.<\/p>\r\n        <p>If the load cannot accept a short power break, use a UPS.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Forgetting Protection Devices<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>An ATS does not replace breakers, fuses, or surge protection.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n  <\/div>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"when-should-you-use-an-automatic-transfer-switch\"><\/span>When Should You Use an Automatic Transfer Switch?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>Use an ATS when a load needs to switch automatically to backup power after the main supply fails.<\/p>\r\n  <p>An ATS is suitable when two AC power sources are available and manual switching is too slow or inconvenient.<\/p>\r\n  <p>It may not be enough for zero-interruption loads, unstable backup sources, unclear wiring systems, or oversized loads.<\/p>\r\n  <p>For sensitive electronics, use an ATS together with a UPS if needed.<\/p>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"frequently-asked-questions-about-automatic-transfer-switches\"><\/span>Frequently Asked Questions About Automatic Transfer Switches<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <div class=\"ats-accordion\">\r\n\r\n    <details>\r\n      <summary>What is the purpose of an automatic transfer switch?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>It transfers the load from normal power to backup power when normal power fails.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>What is an automatic transfer switch used for?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>It is used for backup power switching in homes, small buildings, generator systems, and solar inverter backup systems.<\/p>\r\n        <p>It can also be used in control panels, distribution boards, and telecom cabinets.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>How does an automatic transfer switch work?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>It monitors the normal source and backup source.<\/p>\r\n        <p>When normal power fails and backup power is ready, the ATS transfers the load.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>What happens when utility power comes back?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>The ATS transfers the load back to utility power after the source becomes stable.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Can an ATS work without a generator?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Yes. It can switch between grid power and inverter power, solar backup, two utility sources, or other AC sources.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Is an ATS required for a generator?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Not always.<\/p>\r\n        <p>But an ATS is useful when automatic generator backup transfer is needed.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Can an ATS switch between grid and solar inverter?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Yes, in some systems.<\/p>\r\n        <p>Check inverter output, voltage, frequency, neutral wiring, grounding, and local code first.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>How fast does an ATS switch?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Switching time depends on the ATS design and source condition.<\/p>\r\n        <p>LEEYEE ATS-63 transfer switching time is less than 50 ms.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>What is the transfer switching time of LEEYEE ATS-63?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>It is less than 50 ms according to the product manual.<\/p>\r\n        <p>This is the ATS switching time only. Generator start-up time is separate.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>What is the difference between ATS and UPS?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>An ATS transfers the load between two power sources.<\/p>\r\n        <p>A UPS provides battery power during an interruption.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>What is the difference between 2P and 4P ATS?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>A 2P ATS is commonly used for single-phase systems.<\/p>\r\n        <p>A 4P ATS is commonly used for three-phase systems that switch L1, L2, L3, and Neutral.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Can a 2P ATS be used for a three-phase system?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>No.<\/p>\r\n        <p>A standard three-phase system needs three-phase or four-pole switching.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>What size automatic transfer switch do I need?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Choose by load current, voltage, pole number, source type, wiring method, and transfer requirement.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Can ATS-63 be used for home backup power?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Yes, when the voltage, current, pole number, and wiring method match the home backup system.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Can ATS-63 be used for generator backup?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Yes, if the system parameters and wiring design match the ATS rating.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Can ATS-63 be used for solar backup systems?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Yes, in some solar or inverter backup systems.<\/p>\r\n        <p>Check inverter output, voltage, frequency, neutral switching, and wiring method before selection.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>What certifications are available for LEEYEE ATS?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>LEEYEE automatic transfer switches can be supplied with CE and RoHS documentation.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Does an ATS provide surge protection?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>No. Surge protection requires a separate surge protective device.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>Does an ATS provide overload or short-circuit protection?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>No. Use suitable circuit breakers, fuses, and other protection devices.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n    <details>\r\n      <summary>What should I confirm before buying an ATS?<\/summary>\r\n      <div class=\"ats-accordion-content\">\r\n        <p>Confirm voltage, current, pole number, and frequency.<\/p>\r\n        <p>Also check the source type, wiring method, transfer time, installation space, and certification needs.<\/p>\r\n      <\/div>\r\n    <\/details>\r\n\r\n  <\/div>\r\n\r\n  <div class=\"ats-cta-box\">\r\n    <h2><span class=\"ez-toc-section\" id=\"need-help-choosing-an-ats\"><\/span>Need Help Choosing an ATS?<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n    <p>Tell us your voltage, current, phase type, backup source, transfer requirement, and wiring details.<\/p>\r\n    <p>LEEYEE can help you select a suitable ATS-63 option.<\/p>\r\n    <p>Common uses include generator backup, solar inverter backup, distribution boards, and compact control cabinets.<\/p>\r\n    <div class=\"ats-cta-actions\">\r\n      <a class=\"ats-btn-white\" href=\"https:\/\/www.cnspd.com\/products\/leeyee-automatic-transfer-switch-solar-backup\/\" target=\"_blank\" rel=\"noopener\">View ATS-63 Product<\/a>\r\n      <a class=\"ats-btn-outline open-contact\" href=\"javascript:void(0);\">Request Selection Support<\/a>\r\n    <\/div>\r\n  <\/div>\r\n\r\n  <h2><span class=\"ez-toc-section\" id=\"conclusion\"><\/span>Conclusion<span class=\"ez-toc-section-end\"><\/span><\/h2>\r\n\r\n  <p>An automatic transfer switch moves a load between normal power and backup power.<\/p>\r\n  <p>It is widely used in generator backup, solar inverter backup, and home backup.<\/p>\r\n  <p>It can also be used in small commercial systems, telecom cabinets, control panels, and distribution boards.<\/p>\r\n  <p>Before choosing an ATS, confirm the voltage, current, phase type, and pole number.<\/p>\r\n  <p>Then check the backup source, wiring method, transfer time, and installation conditions.<\/p>\r\n  <p>For compact backup systems, LEEYEE ATS-63 provides 2P and 4P DIN-rail options from 6A to 63A.<\/p>\r\n  <p>Its transfer switching time is less than 50 ms.<\/p>\r\n  <p>A well-selected ATS makes backup power switching easier, safer, and more reliable.<\/p>\r\n\r\n<\/div>\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>Quick Answer An automatic transfer switch, or ATS, switches a load between two power sources. When the main power fails, the ATS moves the load to backup power. The backup source can be a generator, inverter, solar backup system, or another AC source. When the main power comes back and becomes stable, the ATS switches&#8230;<\/p>","protected":false},"author":18,"featured_media":29472,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[490,1,422],"tags":[],"class_list":["post-29476","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-isolator-switching","category-news","category-industry-news"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>What Is an Automatic Transfer Switch? How ATS Works &amp; How to Choose<\/title>\n<meta name=\"description\" content=\"A practical ATS guide for backup power systems. 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