{"id":1796,"date":"2026-07-27T10:33:11","date_gmt":"2026-07-27T02:33:11","guid":{"rendered":"https:\/\/jutrion.com\/?page_id=1796"},"modified":"2026-07-27T10:36:39","modified_gmt":"2026-07-27T02:36:39","slug":"dc-%ec%b0%a8%eb%8b%a8%ea%b8%b0-%ec%a0%95%ea%b2%a9-%ea%b3%84%ec%82%b0%ea%b8%b0","status":"publish","type":"page","link":"https:\/\/jutrion.com\/ko\/tools\/dc-breaker-rating-calculator\/","title":{"rendered":"DC MCB &amp; MCCB \uc815\uaca9 \uacc4\uc0b0\uae30 (PV)"},"content":{"rendered":"\n<!-- ===== JUTRION DC MCB & MCCB 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>DC MCB &amp; MCCB Rating Calculator (PV &amp; Battery)<\/h1>\n  <p class=\"tool-lede\">Screen the rated current, DC operating voltage, pole configuration, and breaking capacity for a DC circuit breaker on a PV array or battery circuit. DC breakers are not AC breakers derated \u2014 the voltage rating and pole arrangement are DC-specific and must come from the device documentation.<\/p>\n\n  <div class=\"jt-card\"><div class=\"jt-grid\">\n    <div class=\"jt-inputs\">\n      <div class=\"jt-field\"><label for=\"jt-app\">Circuit<\/label>\n        <select id=\"jt-app\"><option value=\"pv\" selected>PV array \/ string (I = I<sub>sc<\/sub>)<\/option><option value=\"batt\">Battery \/ DC load (I = load current)<\/option><\/select>\n      <\/div>\n      <div class=\"jt-two\">\n        <div class=\"jt-field\"><label for=\"jt-i\" id=\"jt-ilbl\">Array I<sub>sc<\/sub> (A)<\/label><input type=\"number\" id=\"jt-i\" value=\"30\" min=\"0.1\" step=\"0.1\" inputmode=\"decimal\"><\/div>\n        <div class=\"jt-field\"><label for=\"jt-vdc\">System voltage V<sub>dc<\/sub> (V)<\/label><input type=\"number\" id=\"jt-vdc\" value=\"1000\" min=\"1\" step=\"10\" inputmode=\"numeric\"><\/div>\n      <\/div>\n      <div class=\"jt-two\">\n        <div class=\"jt-field\"><label for=\"jt-iz\">Cable capacity I<sub>z<\/sub> (A) <span>optional<\/span><\/label><input type=\"number\" id=\"jt-iz\" value=\"\" min=\"0\" step=\"1\" inputmode=\"numeric\" placeholder=\"tabulated\"><\/div>\n        <div class=\"jt-field\"><label for=\"jt-isc\">Prospective fault (kA) <span>optional<\/span><\/label><input type=\"number\" id=\"jt-isc\" value=\"\" min=\"0\" step=\"0.1\" inputmode=\"decimal\" placeholder=\"battery\"><\/div>\n      <\/div>\n      <div class=\"jt-note\"><span>\u24d8<\/span><span>For PV the continuous current is the array short-circuit current I<sub>sc<\/sub>; for a battery or DC load it is the maximum continuous load current.<\/span><\/div>\n    <\/div>\n    <div class=\"jt-readout\">\n      <div><div class=\"jt-rl\">Minimum rated current I<sub>n<\/sub><\/div><div class=\"jt-big\"><span id=\"jt-in\">\u2014<\/span> <span>A<\/span><\/div><\/div>\n      <div class=\"jt-rec row\"><div class=\"k\">Rated voltage U<sub>e<\/sub><\/div><div class=\"v\" id=\"jt-ue\">\u2014<\/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      <div class=\"jt-rec\"><div class=\"k\">Checks<\/div><div style=\"margin-top:6px\"><span class=\"jt-pill na\" id=\"jt-chk\">\u2014<\/span><\/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 rating is built<\/h2>\n    <div class=\"jt-eq\">Rated current: I<sub>n<\/sub> \u2265 1.25 \u00d7 continuous current\nRated voltage: U<sub>e<\/sub> \u2265 system V<sub>dc<\/sub> (PV: cold V<sub>oc<\/sub>)\nCable rule:    I<sub>n<\/sub> \u2264 I<sub>z<\/sub><\/div>\n    <p>The 1.25 factor is the continuous-duty margin \u2014 for PV it also covers irradiance and temperature above STC. The rated voltage must cover the highest DC voltage the circuit can reach, which for a PV string is the cold-temperature open-circuit voltage, not the nominal system voltage.<\/p>\n\n    <h2>Why DC poles matter<\/h2>\n    <p>Interrupting DC is harder than AC because there is no natural current zero to help extinguish the arc. Manufacturers achieve a DC voltage rating by <b>connecting poles in series<\/b> so each pole shares the arc voltage. A breaker rated, say, 250 V per pole may need two poles in series for a 500 V circuit and four for 1000 V. The pole count and the required internal connection are stated by the manufacturer \u2014 never assume an AC breaker will interrupt the same DC voltage.<\/p>\n    <div class=\"jt-note\"><span>\u26a0<\/span><span><b>DC rating is not AC rating.<\/b> An AC MCB\/MCCB used on DC without a DC voltage rating and the correct series-pole wiring may fail to clear the arc. Use a device explicitly DC-rated for the voltage, or the PV-specific series.<\/span><\/div>\n\n    <h2>Frequently asked questions<\/h2>\n    <div class=\"jt-faq\">\n      <details><summary>What voltage rating do I need for a 1000 V PV string?<\/summary><p>At least the cold-temperature string open-circuit voltage, which can exceed 1000 V on a cold morning. Use a breaker rated for that DC voltage with the manufacturer&#8217;s specified pole configuration.<\/p><\/details>\n      <details><summary>Does a PV string with only two strings need a breaker?<\/summary><p>A breaker or disconnector is still needed for isolation, but over-current protection between paralleled strings is only required once enough strings are combined to drive a damaging reverse current \u2014 see the string-fuse guidance.<\/p><\/details>\n      <details><summary>Can I use a standard MCCB on a battery circuit?<\/summary><p>Only if it carries a DC voltage rating covering the battery voltage and the required pole arrangement. Battery fault currents can be very high, so the DC breaking capacity must also cover the prospective fault.<\/p><\/details>\n    <\/div>\n\n    <div class=\"jt-cta\">\n      <h2>Select the DC breaker<\/h2>\n      <p>Match the rated current, DC voltage, poles, and breaking capacity to a DC-rated device for the array or battery.<\/p>\n      <div class=\"jt-cta-btns\">\n        <a class=\"jt-btn\" href=\"https:\/\/jutrion.com\/dc-mccb\/\">Explore JUTRION DC MCCBs<\/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\/dc-mccb\/\">DC MCCB<\/a> \u00b7 <a href=\"https:\/\/jutrion.com\/dc-mcb\/\">DC MCB<\/a> \u00b7 <a href=\"https:\/\/jutrion.com\/isolator-switch\/\">Isolator switch<\/a><\/p>\n    <\/div>\n\n    <div class=\"jt-std\"><strong>Standards referenced<\/strong>IEC 60947-2 (circuit-breakers) \u00b7 IEC 60364-7-712 (PV) \u00b7 IEC 62548 (PV array design) \u00b7 manufacturer DC ratings.<\/div>\n    <p class=\"jt-fine\">Screening estimate for guidance only. The final DC breaker current, voltage, pole configuration, and breaking capacity must be confirmed by a qualified person against the manufacturer&#8217;s DC data and the circuit fault level.<\/p>\n  <\/div>\n<\/div>\n\n<script>\n(function(){\n  var $=function(id){return document.getElementById(id);};\n  var app=$('jt-app'),i=$('jt-i'),vdc=$('jt-vdc'),iz=$('jt-iz'),isc=$('jt-isc'),ilbl=$('jt-ilbl'),\n      inEl=$('jt-in'),ueEl=$('jt-ue'),polesEl=$('jt-poles'),chk=$('jt-chk');\n  var LADDER=[1,2,3,4,6,10,13,16,20,25,32,40,50,63,80,100,125,160,200,250,320,400,500,630,800,1000,1250,1600];\n  function nextIn(x){for(var k=0;k<LADDER.length;k++){if(LADDER[k]>=x)return LADDER[k];}return null;}\n  app.addEventListener('change',function(){ilbl.textContent=(app.value==='pv')?'Array Isc (A)':'Load current (A)';calc();});\n  function calc(){\n    var I=parseFloat(i.value),V=parseFloat(vdc.value),Iz=parseFloat(iz.value);\n    if(!(I>0&&V>0)){inEl.textContent='\u2014';ueEl.textContent=polesEl.textContent='\u2014';chk.className='jt-pill na';chk.textContent='\u2014';return;}\n    var need=1.25*I,nr=nextIn(need);\n    inEl.textContent=nr?nr:'> 1600';\n    ueEl.textContent='\u2265 '+V+' V DC';\n    var poles=(V<=250)?1:(V<=500)?2:(V<=800)?3:4;\n    polesEl.textContent=poles+' pole'+(poles>1?'s in series':'');\n    if(Iz>0&&nr){var pass=nr<=Iz;chk.className='jt-pill '+(pass?'ok':'no');chk.textContent=pass?('PASS \u2014 In '+nr+' A \u2264 Iz '+Iz+' A'):('CHECK \u2014 In '+nr+' A > Iz '+Iz+' A');}\n    else{chk.className='jt-pill na';chk.textContent='In \u2265 '+need.toFixed(1)+' A (1.25\u00d7)';}\n  }\n  [i,vdc,iz,isc].forEach(function(el){el.addEventListener('input',calc);el.addEventListener('change',calc);});\n  $('jt-copy').addEventListener('click',function(){var b=$('jt-copy');var txt='Circuit: '+app.options[app.selectedIndex].text+'\\nContinuous I: '+i.value+' A, Vdc: '+vdc.value+' V\\nMin In (1.25\u00d7): '+inEl.textContent+' A\\nRated voltage Ue: '+ueEl.textContent+'\\nPoles: '+polesEl.textContent+'\\nCheck: '+chk.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 DC MCB &amp; MCCB Rating Calculator (PV &amp; Battery) Screen the rated current, DC operating voltage, pole configuration, and breaking capacity for a DC circuit breaker on a PV array or battery circuit. DC breakers are not AC breakers derated \u2014 the voltage rating and pole arrangement are DC-specific and must come [&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-1796","page","type-page","status-publish","hentry"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/jutrion.com\/ko\/wp-json\/wp\/v2\/pages\/1796","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jutrion.com\/ko\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/jutrion.com\/ko\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/jutrion.com\/ko\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jutrion.com\/ko\/wp-json\/wp\/v2\/comments?post=1796"}],"version-history":[{"count":1,"href":"https:\/\/jutrion.com\/ko\/wp-json\/wp\/v2\/pages\/1796\/revisions"}],"predecessor-version":[{"id":1797,"href":"https:\/\/jutrion.com\/ko\/wp-json\/wp\/v2\/pages\/1796\/revisions\/1797"}],"up":[{"embeddable":true,"href":"https:\/\/jutrion.com\/ko\/wp-json\/wp\/v2\/pages\/1778"}],"wp:attachment":[{"href":"https:\/\/jutrion.com\/ko\/wp-json\/wp\/v2\/media?parent=1796"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}