{"id":1790,"date":"2026-07-27T10:33:23","date_gmt":"2026-07-27T02:33:23","guid":{"rendered":"https:\/\/jutrion.com\/?page_id=1790"},"modified":"2026-07-27T10:38:15","modified_gmt":"2026-07-27T02:38:15","slug":"may-tinh-bo-cach-ly-dc-pv","status":"publish","type":"page","link":"https:\/\/jutrion.com\/vi\/tools\/pv-dc-isolator-calculator\/","title":{"rendered":"C\u00f4ng c\u1ee5 t\u00ednh \u0111\u1ecbnh m\u1ee9c b\u1ed9 c\u00e1ch ly DC PV"},"content":{"rendered":"\n<!-- ===== JUTRION PV DC Isolator Rating Calculator \u2014 paste into a WordPress \"Custom HTML\" block ===== -->\n<div class=\"jt-calc\">\n  <p class=\"eyebrow\">Solar &amp; DC<\/p>\n  <h1>PV DC Isolator Rating Calculator<\/h1>\n  <p class=\"tool-lede\">Screen the minimum voltage rating, current rating, utilization category, and pole configuration for a PV array DC isolator (disconnector). A DC isolator must break the array under load at full string voltage, so its ratings come from the cold open-circuit voltage and the short-circuit current, not the nominal figures.<\/p>\n\n  <div class=\"jt-card\"><div class=\"jt-grid\">\n    <div class=\"jt-inputs\">\n      <div class=\"jt-field\"><label for=\"jt-voc\">String cold V<sub>oc<\/sub> (V)<\/label><input type=\"number\" id=\"jt-voc\" value=\"1000\" min=\"1\" step=\"10\" inputmode=\"numeric\"><\/div>\n      <div class=\"jt-field\"><label for=\"jt-isc\">Array I<sub>sc<\/sub> at this point (A)<\/label><input type=\"number\" id=\"jt-isc\" value=\"27.6\" min=\"0.1\" step=\"0.1\" inputmode=\"decimal\"><\/div>\n      <div class=\"jt-field\"><label for=\"jt-fac\">Current margin<\/label>\n        <select id=\"jt-fac\"><option value=\"1.25\" selected>1.25 \u00d7 Isc<\/option><option value=\"1.4\">1.4 \u00d7 Isc (conservative)<\/option><\/select>\n      <\/div>\n      <div class=\"jt-note\"><span>\u24d8<\/span><span>Use the cold-temperature string V<sub>oc<\/sub> for the voltage rating and the array I<sub>sc<\/sub> seen at the isolator (one string, or the combined array) for the current rating.<\/span><\/div>\n    <\/div>\n    <div class=\"jt-readout\">\n      <div><div class=\"jt-rl\">Minimum rated voltage U<sub>e<\/sub><\/div><div class=\"jt-big\"><span id=\"jt-ue\">\u2014<\/span> <span>V<\/span><\/div><\/div>\n      <div class=\"jt-rec row\"><div class=\"k\">Minimum rated current I<sub>e<\/sub><\/div><div class=\"v\" id=\"jt-ie\">\u2014<\/div><\/div>\n      <div class=\"jt-rec row\"><div class=\"k\">Utilization category<\/div><div class=\"v\" id=\"jt-cat\">DC-PV2<\/div><\/div>\n      <div class=\"jt-rec row\"><div class=\"k\">Poles (in series)<\/div><div class=\"v\" id=\"jt-poles\">\u2014<\/div><\/div>\n      <button type=\"button\" class=\"jt-copy\" id=\"jt-copy\">Copy result<\/button>\n    <\/div>\n  <\/div><\/div>\n\n  <div class=\"jt-content\">\n    <h2>How the ratings are set<\/h2>\n    <div class=\"jt-eq\">Rated voltage U<sub>e<\/sub> \u2265 string cold V<sub>oc<\/sub>\nRated current I<sub>e<\/sub> \u2265 1.25 \u00d7 I<sub>sc<\/sub>\nCategory: DC-PV2 (IEC 60947-3), on-load PV switching<\/div>\n    <p>The isolator has to open while the array is generating, so it must interrupt a DC arc at the highest voltage the string can reach \u2014 the cold open-circuit voltage. The current rating carries the array short-circuit current with a continuous-duty margin, because a PV source sits close to its short-circuit current in normal operation.<\/p>\n\n    <h2>Why DC-PV2 and series poles<\/h2>\n    <p>The <b>DC-PV2<\/b> utilization category (IEC 60947-3) certifies a switch to make and break a PV array on load, including the arc energy of a DC source with no natural current zero. As with DC breakers, the voltage rating is reached by putting <b>poles in series<\/b> so each shares the arc voltage \u2014 a 1000 V array typically needs several poles internally connected as the manufacturer specifies.<\/p>\n    <div class=\"jt-note\"><span>\u26a0<\/span><span><b>An AC switch-disconnector is not a PV DC isolator.<\/b> Without a DC-PV rating and the correct series-pole wiring, it may not extinguish the arc when opening a live array. Use a device rated DC-PV2 for the string voltage.<\/span><\/div>\n\n    <h2>Frequently asked questions<\/h2>\n    <div class=\"jt-faq\">\n      <details><summary>Where is a PV DC isolator required?<\/summary><p>An accessible load-break isolator is normally required at the array and at the inverter so the DC side can be safely disconnected for maintenance. Local rules and IEC 60364-7-712 set the exact positions.<\/p><\/details>\n      <details><summary>Do I size current on Isc or Impp?<\/summary><p>On I<sub>sc<\/sub> with the continuous margin. A PV source&#8217;s operating current sits close to its short-circuit current, so I<sub>sc<\/sub> \u00d7 1.25 is the conservative continuous rating.<\/p><\/details>\n      <details><summary>How many poles do I need?<\/summary><p>Enough that the device&#8217;s per-pole DC voltage, multiplied by the series poles, covers the cold string voltage \u2014 the manufacturer states the configuration. Do not reduce poles to save space.<\/p><\/details>\n    <\/div>\n\n    <div class=\"jt-cta\">\n      <h2>Select the DC isolator<\/h2>\n      <p>Match the DC-PV2 rating, voltage, current, and poles to an isolator for the array or inverter position.<\/p>\n      <div class=\"jt-cta-btns\">\n        <a class=\"jt-btn\" href=\"https:\/\/jutrion.com\/isolator-switch\/\">Explore JUTRION isolators<\/a>\n        <a class=\"jt-btn ghost\" href=\"https:\/\/jutrion.com\/contact\/\">Get a free quote<\/a>\n      <\/div>\n      <p class=\"jt-related\">Related products: <a href=\"https:\/\/jutrion.com\/isolator-switch\/\">Isolator switch<\/a> \u00b7 <a href=\"https:\/\/jutrion.com\/dc-mccb\/\">DC MCCB<\/a> \u00b7 <a href=\"https:\/\/jutrion.com\/pv-combiner-box\/\">PV combiner box<\/a><\/p>\n    <\/div>\n\n    <div class=\"jt-std\"><strong>Standards referenced<\/strong>IEC 60947-3 (switches, disconnectors, DC-PV2) \u00b7 IEC 60364-7-712 (PV systems) \u00b7 IEC 62548 (PV array design).<\/div>\n    <p class=\"jt-fine\">Screening estimate for guidance only. Final isolator ratings, category, and pole configuration must be confirmed by a qualified person against the manufacturer&#8217;s DC data and the array design.<\/p>\n  <\/div>\n<\/div>\n\n<script>\n(function(){\n  var $=function(id){return document.getElementById(id);};\n  var voc=$('jt-voc'),isc=$('jt-isc'),fac=$('jt-fac'),\n      ueEl=$('jt-ue'),ieEl=$('jt-ie'),polesEl=$('jt-poles');\n  function calc(){\n    var V=parseFloat(voc.value),I=parseFloat(isc.value),f=parseFloat(fac.value);\n    if(!(V>0&&I>0)){ueEl.textContent='\u2014';ieEl.textContent=polesEl.textContent='\u2014';return;}\n    ueEl.textContent='\u2265 '+V;\n    ieEl.textContent='\u2265 '+(f*I).toFixed(1)+' A';\n    var poles=(V<=250)?1:(V<=500)?2:(V<=800)?3:4;\n    polesEl.textContent=poles+' pole'+(poles>1?'s in series':'');\n  }\n  [voc,isc,fac].forEach(function(el){el.addEventListener('input',calc);el.addEventListener('change',calc);});\n  $('jt-copy').addEventListener('click',function(){var b=$('jt-copy');var txt='String cold Voc: '+voc.value+' V, Isc '+isc.value+' A\\nMin Ue: '+ueEl.textContent+' V\\nMin Ie: '+ieEl.textContent+'\\nCategory: DC-PV2\\nPoles: '+polesEl.textContent;navigator.clipboard.writeText(txt).then(function(){var o=b.textContent;b.textContent='Copied \u2713';setTimeout(function(){b.textContent=o;},1500);}).catch(function(){b.textContent='Press Ctrl+C';});});\n  calc();\n})();\n<\/script>\n<!-- ===== end block ===== -->\n\n","protected":false},"excerpt":{"rendered":"<p>Solar &amp; DC PV DC Isolator Rating Calculator Screen the minimum voltage rating, current rating, utilization category, and pole configuration for a PV array DC isolator (disconnector). A DC isolator must break the array under load at full string voltage, so its ratings come from the cold open-circuit voltage and the short-circuit current, not the [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1778,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1790","page","type-page","status-publish","hentry"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/jutrion.com\/vi\/wp-json\/wp\/v2\/pages\/1790","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jutrion.com\/vi\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/jutrion.com\/vi\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/jutrion.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jutrion.com\/vi\/wp-json\/wp\/v2\/comments?post=1790"}],"version-history":[{"count":1,"href":"https:\/\/jutrion.com\/vi\/wp-json\/wp\/v2\/pages\/1790\/revisions"}],"predecessor-version":[{"id":1791,"href":"https:\/\/jutrion.com\/vi\/wp-json\/wp\/v2\/pages\/1790\/revisions\/1791"}],"up":[{"embeddable":true,"href":"https:\/\/jutrion.com\/vi\/wp-json\/wp\/v2\/pages\/1778"}],"wp:attachment":[{"href":"https:\/\/jutrion.com\/vi\/wp-json\/wp\/v2\/media?parent=1790"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}