{"id":1822,"date":"2026-07-27T10:32:02","date_gmt":"2026-07-27T02:32:02","guid":{"rendered":"https:\/\/jutrion.com\/?page_id=1822"},"modified":"2026-07-27T10:37:02","modified_gmt":"2026-07-27T02:37:02","slug":"kalkulator-pradu-obciazenia-i-mocy","status":"publish","type":"page","link":"https:\/\/jutrion.com\/pl\/tools\/load-current-power-calculator\/","title":{"rendered":"kalkulator pr\u0105du obci\u0105\u017cenia"},"content":{"rendered":"\n<!-- ===== JUTRION Load Current & Power Calculator \u2014 paste into a WordPress \"Custom HTML\" block ===== -->\n<div class=\"jt-calc\">\n  <p class=\"eyebrow\">Power distribution<\/p>\n  <h1>Load Current &amp; Power Calculator (kW \u00b7 kVA \u00b7 A)<\/h1>\n  <p class=\"tool-lede\">Convert between active power (kW), apparent power (kVA), and current (A) for DC, single-phase, and balanced three-phase loads. A fast starting point for sizing breakers, contactors, ATS, CTs, and cables.<\/p>\n\n  <div class=\"jt-card\"><div class=\"jt-grid\">\n    <div class=\"jt-inputs\">\n      <div class=\"jt-field\"><label>System<\/label>\n        <div class=\"jt-seg\" id=\"jt-sys\"><button type=\"button\" data-s=\"3\" aria-pressed=\"true\">3-phase<\/button><button type=\"button\" data-s=\"1\" aria-pressed=\"false\">1-phase<\/button><button type=\"button\" data-s=\"dc\" aria-pressed=\"false\">DC<\/button><\/div>\n      <\/div>\n      <div class=\"jt-field\"><label>Known value<\/label>\n        <div class=\"jt-inline\">\n          <input type=\"number\" id=\"jt-val\" value=\"30\" min=\"0\" step=\"0.1\" inputmode=\"decimal\" aria-label=\"Value\">\n          <select id=\"jt-mode\" aria-label=\"Known quantity\"><option value=\"kw\" selected>kW<\/option><option value=\"kva\">kVA<\/option><option value=\"a\">A<\/option><\/select>\n        <\/div>\n      <\/div>\n      <div class=\"jt-two\">\n        <div class=\"jt-field\"><label for=\"jt-volt\">Voltage (V)<\/label><input type=\"number\" id=\"jt-volt\" value=\"400\" min=\"1\" step=\"1\" inputmode=\"numeric\"><\/div>\n        <div class=\"jt-field\"><label for=\"jt-pf\">Power factor<\/label><input type=\"number\" id=\"jt-pf\" value=\"0.85\" min=\"0.1\" max=\"1\" step=\"0.01\" inputmode=\"decimal\"><\/div>\n      <\/div>\n      <div class=\"jt-note\"><span>\u24d8<\/span><span>Power factor is used for AC only. For DC it is treated as 1 and kW = kVA.<\/span><\/div>\n    <\/div>\n    <div class=\"jt-readout\">\n      <div><div class=\"jt-rl\">Current<\/div><div class=\"jt-big\"><span id=\"jt-a\">\u2014<\/span> <span>A<\/span><\/div><\/div>\n      <div class=\"jt-rec\"><div class=\"k\">Active power<\/div><div class=\"v\"><span id=\"jt-kw\">\u2014<\/span> <small>kW<\/small><\/div><\/div>\n      <div class=\"jt-rec\"><div class=\"k\">Apparent power<\/div><div class=\"v\"><span id=\"jt-kva\">\u2014<\/span> <small>kVA<\/small><\/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>Formulas used<\/h2>\n    <div class=\"jt-eq\">Three-phase:  I = S \/ (\u221a3 \u00d7 V)      S(kVA) = \u221a3 \u00d7 V \u00d7 I \/ 1000      P = S \u00d7 cos \u03c6\nSingle-phase: I = S \/ V           S(kVA) = V \u00d7 I \/ 1000\nDC:           I = P \/ V           (cos \u03c6 = 1, kW = kVA)<\/div>\n    <p>where <b>I<\/b> is line current (A), <b>V<\/b> is voltage (V), <b>S<\/b> is apparent power (kVA), <b>P<\/b> is active power (kW), and <b>cos \u03c6<\/b> is power factor. Enter any one of kW, kVA, or A, and the calculator returns the other two.<\/p>\n\n    <h2>Frequently asked questions<\/h2>\n    <div class=\"jt-faq\">\n      <details><summary>What is the difference between kW and kVA?<\/summary><p>kW is the active (real) power that does work; kVA is the apparent power the circuit must carry. They are related by the power factor: kW = kVA \u00d7 cos \u03c6. Cables, breakers, and transformers are sized on kVA \/ current, not kW alone.<\/p><\/details>\n      <details><summary>Which voltage do I enter for three-phase?<\/summary><p>The line-to-line voltage (for example 400 V), because the \u221a3 formula uses the line voltage.<\/p><\/details>\n    <\/div>\n\n    <div class=\"jt-cta\">\n      <h2>Size the device next<\/h2>\n      <p>With the current known, size the breaker, contactor, or transfer switch \u2014 or ask JUTRION for a suitable product for your market.<\/p>\n      <div class=\"jt-cta-btns\">\n        <a class=\"jt-btn\" href=\"https:\/\/jutrion.com\/products\/\">Browse JUTRION products<\/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\/mccb\/\">MCCB<\/a> \u00b7 <a href=\"https:\/\/jutrion.com\/ac-contactor\/\">AC Contactor<\/a> \u00b7 <a href=\"https:\/\/jutrion.com\/ats\/\">ATS<\/a><\/p>\n    <\/div>\n\n    <div class=\"jt-std\"><strong>Standards referenced<\/strong>IEC 60038 (standard voltages) \u00b7 basic three-phase power relationships (P = \u221a3 \u00b7 V \u00b7 I \u00b7 cos \u03c6).<\/div>\n    <p class=\"jt-fine\">Engineering estimate for guidance only. Final sizing must account for the actual load, diversity, harmonics, and the applicable installation rules, verified by a qualified person.<\/p>\n  <\/div>\n<\/div>\n\n<script>\n(function(){\n  var $=function(id){return document.getElementById(id);};\n  var val=$('jt-val'),mode=$('jt-mode'),volt=$('jt-volt'),pf=$('jt-pf'),aEl=$('jt-a'),kwEl=$('jt-kw'),kvaEl=$('jt-kva');\n  var sys='3';\n  document.querySelectorAll('#jt-sys button').forEach(function(b){b.addEventListener('click',function(){sys=b.dataset.s;document.querySelectorAll('#jt-sys button').forEach(function(x){x.setAttribute('aria-pressed',x===b?'true':'false');});pf.disabled=(sys==='dc');if(sys==='1'&&volt.value==='400')volt.value='230';if(sys==='3'&&volt.value==='230')volt.value='400';calc();});});\n  function r(x){return Math.round(x*100)\/100;}\n  function calc(){\n    var v=parseFloat(volt.value),x=parseFloat(val.value),f=(sys==='dc')?1:parseFloat(pf.value);\n    if(!(v>0&&x>0&&f>0)){aEl.textContent='\u2014';kwEl.textContent='\u2014';kvaEl.textContent='\u2014';return;}\n    var k=(sys==='3')?Math.sqrt(3):1; \/\/ multiplier for line calc; dc\/1ph = 1\n    var A,S,P;\n    if(mode.value==='a'){A=x;S=(sys==='dc')?(v*A\/1000):(k*v*A\/1000);P=(sys==='dc')?S:S*f;}\n    else if(mode.value==='kva'){S=x;A=(sys==='dc')?(S*1000\/v):(S*1000\/(k*v));P=(sys==='dc')?S:S*f;}\n    else{P=x;S=(sys==='dc')?P:P\/f;A=(sys==='dc')?(P*1000\/v):(S*1000\/(k*v));}\n    aEl.textContent=r(A);kwEl.textContent=r(P);kvaEl.textContent=r(S);\n  }\n  [val,mode,volt,pf].forEach(function(el){el.addEventListener('input',calc);el.addEventListener('change',calc);});\n  $('jt-copy').addEventListener('click',function(){var b=$('jt-copy');var txt='System: '+(sys==='dc'?'DC':sys+'-phase')+', '+volt.value+' V\\nCurrent: '+aEl.textContent+' A\\nActive power: '+kwEl.textContent+' kW\\nApparent power: '+kvaEl.textContent+' kVA';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>Power distribution Load Current &amp; Power Calculator (kW \u00b7 kVA \u00b7 A) Convert between active power (kW), apparent power (kVA), and current (A) for DC, single-phase, and balanced three-phase loads. A fast starting point for sizing breakers, contactors, ATS, CTs, and cables. System 3-phase1-phaseDC Known value kWkVAA Voltage (V) Power factor \u24d8Power factor is used [&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-1822","page","type-page","status-publish","hentry"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/jutrion.com\/pl\/wp-json\/wp\/v2\/pages\/1822","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jutrion.com\/pl\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/jutrion.com\/pl\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/jutrion.com\/pl\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jutrion.com\/pl\/wp-json\/wp\/v2\/comments?post=1822"}],"version-history":[{"count":1,"href":"https:\/\/jutrion.com\/pl\/wp-json\/wp\/v2\/pages\/1822\/revisions"}],"predecessor-version":[{"id":1823,"href":"https:\/\/jutrion.com\/pl\/wp-json\/wp\/v2\/pages\/1822\/revisions\/1823"}],"up":[{"embeddable":true,"href":"https:\/\/jutrion.com\/pl\/wp-json\/wp\/v2\/pages\/1778"}],"wp:attachment":[{"href":"https:\/\/jutrion.com\/pl\/wp-json\/wp\/v2\/media?parent=1822"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}