{"id":2104,"date":"2026-10-14T20:08:58","date_gmt":"2026-10-14T19:08:58","guid":{"rendered":"https:\/\/wpcalc.com\/pt\/engenharia\/queda-de-tensao-eletrica\/"},"modified":"2026-10-14T20:08:58","modified_gmt":"2026-10-14T19:08:58","slug":"queda-de-tensao-eletrica","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/pt\/engenharia\/queda-de-tensao-eletrica\/","title":{"rendered":"Queda de tens\u00e3o el\u00e9trica"},"content":{"rendered":"<section class=\"not-prose calculator-box\" aria-labelledby=\"calculator-title\"><div class=\"flex items-baseline sm:items-center justify-between gap-2 sm:gap-3\"><div class=\"flex flex-col sm:flex-row sm:items-center gap-2\"><span class=\"icon icon-calculator text-primary-700! text-base! dark:text-primary-300!\" aria-hidden=\"true\"><\/span><h2 id=\"calculator-title\" class=\"text-lg font-display font-bold\">Estime a perda de tens\u00e3o ao longo do cabo<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"2104\" data-favorite-title=\"Queda de tens\u00e3o\" data-favorite-url=\"https:\/\/wpcalc.com\/pt\/engenharia\/queda-de-tensao-eletrica\/\" data-favorite-excerpt=\"Calcule a queda de tens\u00e3o em um cabo de cobre, alum\u00ednio ou prata. Informe a corrente, a tens\u00e3o de alimenta\u00e7\u00e3o, o comprimento e a se\u00e7\u00e3o do condutor para obter a queda em volts, em porcentagem e a tens\u00e3o na carga.\" aria-label=\"Adicionar aos favoritos\" data-favorite-icon=\"icon icon-electrical\">\n    <span class=\"icon icon-shape-star-empty\" aria-hidden=\"true\"><\/span>\n  <\/button>\n  <div class=\"calcdash-favorite__tip\" aria-hidden=\"true\">\n   <span class=\"favorite-tooltip\" id=\"favorite-tooltip\"><\/span>\n  <\/div>\n  <span class=\"sr-only\" role=\"status\" id=\"favorite-status\"><\/span>\n<\/div><\/div><form action=\"https:\/\/wpcalc.com\/pt\/engenharia\/queda-de-tensao-eletrica\/\" method=\"POST\" class=\"calculator\" id=\"calculator-2104\" data-post=\"2104\"><fieldset class=\"fieldset-input is-2\"><legend class=\"sr-only\">Campos de entrada<\/legend><div class=\"field has-term\" id=\"input-1\"><label for=\"field-1\">Corrente (I)<\/label><div class=\"term\">I<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"corrente_i\" id=\"field-1\" aria-describedby=\"calc-unit-1 calc-info-1\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0.001\" value=\"15\"\/><div class=\"unit\" id=\"calc-unit-1\">A<\/div><small id=\"calc-info-1\">Corrente da carga que percorre o condutor<\/small><\/div><div class=\"field has-term\" id=\"input-2\"><label for=\"field-2\">Tens\u00e3o de alimenta\u00e7\u00e3o<\/label><div class=\"term\">V\u2080<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"tenso_de_alimentao\" id=\"field-2\" aria-describedby=\"calc-unit-2 calc-info-2\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"1\" value=\"230\"\/><div class=\"unit\" id=\"calc-unit-2\">V<\/div><small id=\"calc-info-2\">Tens\u00e3o nominal na fonte (fase-fase, no caso trif\u00e1sico)<\/small><\/div><div class=\"field\" id=\"input-3\"><label for=\"field-3\">Tipo de circuito<\/label><div class=\"grid grid-cols-1\"><select id=\"field-3\" name=\"tipo_de_circuito\"><option value=\"single\" selected>Single-phase (2-wire, AC or DC)<\/option><option value=\"three\">Trif\u00e1sico (3 fios, CA)<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><div class=\"field has-term\" id=\"input-4\"><label for=\"field-4\">Comprimento do condutor (L)<\/label><div class=\"term\">L<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"comprimento_do_condutor_l\" id=\"field-4\" aria-describedby=\"calc-info-4\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0.001\" value=\"30\"\/><div class=\"grid grid-cols-1\"><select id=\"field-5\" name=\"unidade_de_comprimento\" aria-label=\"Unidade de comprimento\"><option value=\"m\" selected>m<\/option><option value=\"ft\">ft<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-4\">Percurso do cabo, em um s\u00f3 sentido, da fonte at\u00e9 a carga<\/small><\/div><div class=\"field has-term\" id=\"input-5\"><label for=\"field-6\">Se\u00e7\u00e3o transversal (A)<\/label><div class=\"term\">A<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"seo_transversal_a\" id=\"field-6\" aria-describedby=\"calc-info-6\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0.001\" value=\"2.5\"\/><div class=\"grid grid-cols-1\"><select id=\"field-7\" name=\"unidade_de_rea\" aria-label=\"Unidade de \u00e1rea\"><option value=\"mm2\" selected>mm\u00b2<\/option><option value=\"kcmil\">kcmil (MCM)<\/option><option value=\"in2\">in\u00b2<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-6\">Se\u00e7\u00e3o transversal de um condutor isolado<\/small><\/div><div class=\"field\" id=\"input-6\"><label for=\"field-8\">Material do condutor<\/label><div class=\"grid grid-cols-1\"><select id=\"field-8\" name=\"material_do_condutor\"><option value=\"copper\" selected>Cobre (\u03c1 = 0,0172)<\/option><option value=\"aluminum\">Alum\u00ednio (\u03c1 = 0,0282)<\/option><option value=\"silver\">Prata (\u03c1 = 0,0159)<\/option><option value=\"custom\">Resistividade personalizada<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><div class=\"field has-term\" id=\"input-7\"><label for=\"field-9\">Resistividade personalizada (\u03c1)<\/label><div class=\"term\">\u03c1<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"resistividade_personalizada_\" id=\"field-9\" aria-describedby=\"calc-unit-9 calc-info-9\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"1.0E-6\" value=\"0.0172\"\/><div class=\"unit\" id=\"calc-unit-9\">\u03a9\u00b7mm\u00b2\/m<\/div><small id=\"calc-info-9\">Usada apenas quando Material est\u00e1 definido como &quot;Resistividade personalizada&quot;<\/small><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Recalcular\" id=\"calculate-button\" data-post=\"2104\">Calcular<\/button><button type=\"reset\">Redefinir<\/button><\/div><div class=\"field is-checkbox hidden!\" id=\"field-auto-calc\"><input type=\"checkbox\" id=\"auto-calc\"><label for=\"auto-calc\">Calcular automaticamente<\/label><small>Se ativado, o resultado \u00e9 atualizado automaticamente quando voc\u00ea altera qualquer valor.<\/small><\/div><div class=\"fieldset-result is-hidden\" aria-labelledby=\"result-title\" aria-live=\"polite\" role=\"region\"> <h3 class=\"result-title bg-gradient-to-r from-primary-50 to-gray-50 dark:from-primary-900 dark:to-gray-800\" id=\"result-title\"><span class=\"icon icon-s-pulse\" aria-hidden=\"true\"><\/span> Resultados da queda de tens\u00e3o<\/h3><div class=\"result-box\"><div class=\"field-result\" id=\"output-1\"><span class=\"field-title\"><span>Queda de tens\u00e3o<\/span><span class=\"result-term\">Vd<\/span><\/span><span class=\"field-value\" id=\"result-1\" data-unit=\"V\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-2\"><span class=\"field-title\"><span>Queda de tens\u00e3o (% da alimenta\u00e7\u00e3o)<\/span><span class=\"result-term\">Vd%<\/span><\/span><span class=\"field-value\" id=\"result-2\" data-unit=\"%\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-3\"><span class=\"field-title\"><span>Tens\u00e3o na carga<\/span><span class=\"result-term\">VL<\/span><\/span><span class=\"field-value\" id=\"result-3\" data-unit=\"V\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result is-column\" id=\"output-4\"><span class=\"field-title\"><span>Avalia\u00e7\u00e3o e f\u00f3rmula<\/span><\/span><span class=\"field-value\" id=\"result-4\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><\/div><div class=\"result-actions\"><button type=\"button\" class=\"copy-link\"><svg viewBox=\"0 0 20 20\" fill=\"currentColor\" aria-hidden=\"true\"><path d=\"M12.232 4.232a2.5 2.5 0 0 1 3.536 3.536l-1.225 1.224a.75.75 0 0 0 1.061 1.06l1.224-1.224a4 4 0 0 0-5.656-5.656l-3 3a4 4 0 0 0 .225 5.865.75.75 0 0 0 .977-1.138 2.5 2.5 0 0 1-.142-3.667l3-3Z\"\/><path d=\"M11.603 7.963a.75.75 0 0 0-.977 1.138 2.5 2.5 0 0 1 .142 3.667l-3 3a2.5 2.5 0 0 1-3.536-3.536l1.225-1.224a.75.75 0 0 0-1.061-1.06l-1.224 1.224a4 4 0 1 0 5.656 5.656l3-3a4 4 0 0 0-.225-5.865Z\"\/><\/svg><span class=\"copy-link__text\">Copiar link para este c\u00e1lculo<\/span><\/button><span class=\"sr-only\" role=\"status\" id=\"copy-link-status\"><\/span><\/div><\/div><a href=\"#respond\" class=\"hidden transition-opacity duration-300 opacity-0 w-50 text-sm justify-center items-center gap-2 px-4 py-2 rounded bg-gray-200 text-gray-700 hover:bg-gray-300\" id=\"leave-comment\"><span class=\"icon icon-comments\" aria-hidden=\"true\"><\/span>Deixar um coment\u00e1rio<\/a><\/form><\/section><section id=\"calc-reactions\" class=\"not-prose hidden my-12 bg-gradient-to-r from-primary-50 to-gray-50 border border-indigo-100 rounded-xl px-6 py-4 shadow-sm\" data-post=\"2104\" aria-live=\"polite\" aria-labelledby=\"calc-reactions-title\"><p id=\"calc-reactions-title\" class=\"text-sm text-gray-500 text-center mb-2\">O que voc\u00ea achou deste resultado?<\/p><div role=\"group\" aria-labelledby=\"calc-reactions-title\" class=\"grid grid-cols-3 sm:flex sm:flex-row sm:justify-around gap-4 sm:items-center sm:flex-wrap\"><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"like\"><span class=\"reaction-count\" data-reaction-count=\"like\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude00 <\/span><span class=\"reaction-description font-medium\">Curti <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"helpful\"><span class=\"reaction-count\" data-reaction-count=\"helpful\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\udca1 <\/span><span class=\"reaction-description font-medium\">\u00datil <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"confused\"><span class=\"reaction-count\" data-reaction-count=\"confused\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude15 <\/span><span class=\"reaction-description font-medium\">Confuso <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"disappointed\"><span class=\"reaction-count\" data-reaction-count=\"disappointed\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude1e <\/span><span class=\"reaction-description font-medium\">Decepcionado <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"inaccurate\"><span class=\"reaction-count\" data-reaction-count=\"inaccurate\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\u274c <\/span><span class=\"reaction-description font-medium\">Impreciso <\/span><\/button><\/div><div id=\"reaction-message\" class=\"hidden mt-8 rounded-md border border-primary-100 bg-white\/50 backdrop-blur-sm px-4 py-2 text-sm text-center shadow-sm\"><\/div><\/section><div class=\"calcdash-ad not-prose calcdash-ad--calc_result calcdash-ad--in-article\"><ins class=\"adsbygoogle\" style=\"display:block\" data-ad-client=\"ca-pub-1721569815777345\" data-ad-slot=\"6317458308\" data-ad-layout=\"in-article\" data-ad-format=\"fluid\"><\/ins><script>(adsbygoogle = window.adsbygoogle || []).push({});<\/script><\/div>\n<style id=\"wpcoderpro-inline-1\">.formula-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section class=\"formula-box\" aria-labelledby=\"formula-title\">\r\n\t<div id=\"formula-title\" class=\"not-prose font-display mb-4\"><span class=\"icon icon-formula\" aria-hidden=\"true\"><\/span><h2>Queda de tens\u00e3o<\/h2><\/div>\r\n\t<figure class=\"not-prose formula\">\r\n\t\t<figcaption class=\"formula-title\">F\u00f3rmula<\/figcaption>\r\n\t\t<div class=\"text-base text-gray-800\" id=\"formula\">\n\\[ V_d = 2 \\cdot I \\cdot \\frac{\\rho \\, L}{A} \\quad \\text{(monof\u00e1sico \/ CC)} \\\\ V_d = \\sqrt{3} \\cdot I \\cdot \\frac{\\rho \\, L}{A} \\quad \\text{(trif\u00e1sico)} \\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Onde:<\/strong><\/p>\n<ul>\n<li>\\(V_d\\) \u2014 queda de tens\u00e3o (V)<\/li>\n<li>\\(I\\) \u2014 corrente da carga (A)<\/li>\n<li>\\(\\rho\\) \u2014 resistividade do material do condutor (\u03a9\u00b7mm\u00b2\/m)<\/li>\n<li>\\(L\\) \u2014 comprimento do trecho, em um s\u00f3 sentido (m)<\/li>\n<li>\\(A\\) \u2014 \u00e1rea da se\u00e7\u00e3o transversal de um condutor (mm\u00b2)<\/li>\n<\/ul>\n<p>O fator 2 considera os condutores de ida e de retorno em um circuito monof\u00e1sico ou de corrente cont\u00ednua, enquanto \\(\\sqrt{3} \\approx 1.732\\) se aplica a circuitos trif\u00e1sicos equilibrados.<\/p>\n<p>\r\n<\/section>\n<style id=\"wpcoderpro-inline-2\">.calculation-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section id=\"calculation\" class=\"calculation-box\" aria-labelledby=\"calculation-title\">\r\n\t<div id=\"calculation-title\" class=\"not-prose font-display\"><span class=\"icon icon-unordered-list\" aria-hidden=\"true\"><\/span><h2>Queda de tens\u00e3o \u2013 exemplo de c\u00e1lculo<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Exemplo:<\/strong> uma carga monof\u00e1sica de 15 A \u00e9 alimentada a 230 V por um cabo de cobre de 30 m com se\u00e7\u00e3o de 2,5 mm\u00b2 (\\(\\rho\\) = 0,0172 \u03a9\u00b7mm\u00b2\/m).<\/p>\n<p>\\[ V_d = 2 \\times 15 \\times \\frac{0.0172 \\times 30}{2.5} = 6.192 \\ \\text{V} \\]<\/p>\n<p>\\[ V_d\\% = \\frac{6.192}{230} \\times 100 = 2.69\\% \\]<\/p>\n<p><strong>Resultado:<\/strong> a queda de tens\u00e3o \u00e9 de 6,19 V, ou 2,69% da alimenta\u00e7\u00e3o, deixando 223,81 V na carga \u2014 dentro do limite de 3% recomendado para circuitos ramificados.<\/p>\n<p>\n\r\n<\/section>\n<h2>Como usar a calculadora<\/h2>\n<ol>\n<li>Informe a <strong>corrente (I)<\/strong> consumida pela carga, em amperes.<\/li>\n<li>Informe a <strong>tens\u00e3o de alimenta\u00e7\u00e3o<\/strong> na fonte. Em circuitos trif\u00e1sicos, use a tens\u00e3o de linha (por exemplo, 400 V).<\/li>\n<li>Selecione o <strong>tipo de circuito<\/strong>: monof\u00e1sico (2 fios, CA ou CC) ou trif\u00e1sico (3 fios, CA).<\/li>\n<li>Informe o <strong>comprimento do condutor (L)<\/strong> \u2014 a dist\u00e2ncia em um s\u00f3 sentido da fonte at\u00e9 a carga \u2014 e escolha metros ou p\u00e9s.<\/li>\n<li>Informe a <strong>\u00e1rea da se\u00e7\u00e3o transversal (A)<\/strong> de um condutor e escolha mm\u00b2, kcmil (MCM) ou in\u00b2.<\/li>\n<li>Escolha o <strong>material do condutor<\/strong>. Se o seu material n\u00e3o estiver na lista, selecione \"Resistividade personalizada\" e informe \\(\\rho\\) em \u03a9\u00b7mm\u00b2\/m.<\/li>\n<li>Leia os resultados: queda de tens\u00e3o em volts, queda em porcentagem da alimenta\u00e7\u00e3o, tens\u00e3o na carga e uma avalia\u00e7\u00e3o em rela\u00e7\u00e3o aos limites recomendados pela NEC.<\/li>\n<\/ol>\n<h2>O que \u00e9 queda de tens\u00e3o?<\/h2>\n<p>Todo condutor tem resist\u00eancia e, quando a corrente o percorre, parte da energia el\u00e9trica \u00e9 perdida na forma de calor. Essa perda aparece como uma redu\u00e7\u00e3o da tens\u00e3o entre a fonte e a carga \u2014 a queda de tens\u00e3o. A carga no final de um cabo longo, portanto, recebe menos tens\u00e3o do que a alimenta\u00e7\u00e3o fornece: uma fonte de 230 V com uma queda de 6 V no cabo entrega apenas 224 V ao aparelho.<\/p>\n<p>A queda aumenta com a corrente, o comprimento do cabo e a resistividade, e diminui \u00e0 medida que a se\u00e7\u00e3o do condutor aumenta. \u00c9 por isso que trechos longos de cabo costumam exigir fios mais grossos: dobrar a se\u00e7\u00e3o corta a resist\u00eancia pela metade e, com ela, a queda. Como o cobre conduz melhor que o alum\u00ednio, um cabo de cobre pode ser menor que um de alum\u00ednio para a mesma queda.<\/p>\n<p>Uma queda de tens\u00e3o excessiva causa mais do que apenas desperd\u00edcio de energia. Motores superaquecem e perdem torque, l\u00e2mpadas incandescentes ficam mais fracas, aquecedores produzem menos e equipamentos eletr\u00f4nicos podem falhar ou reiniciar. Por isso, a maioria das normas limita a queda: a NEC recomenda no m\u00e1ximo 3% em um circuito ramificado e 5% da entrada de energia at\u00e9 a carga final, enquanto a IEC normalmente sugere 3 a 5%, dependendo da aplica\u00e7\u00e3o.<\/p>\n<h2>Premissas e limita\u00e7\u00f5es<\/h2>\n<ul>\n<li><strong>Modelo de resist\u00eancia em corrente cont\u00ednua.<\/strong> O c\u00e1lculo usa apenas a resist\u00eancia do condutor. A indut\u00e2ncia e a capacit\u00e2ncia do cabo s\u00e3o desconsideradas, o que \u00e9 aceit\u00e1vel para instala\u00e7\u00f5es el\u00e9tricas prediais t\u00edpicas em 50\/60 Hz. Em trechos muito longos com correntes elevadas, o efeito pelicular e a reat\u00e2ncia adicionam uma queda extra que n\u00e3o \u00e9 capturada aqui.<\/li>\n<li><strong>Resistividade a 20 \u00b0C.<\/strong> Os valores embutidos (cobre 0,0172, alum\u00ednio 0,0282, prata 0,0159 \u03a9\u00b7mm\u00b2\/m) valem perto da temperatura ambiente. A resist\u00eancia do cobre aumenta cerca de 0,4% por \u00b0C, ent\u00e3o um cabo quente em um forro ou enterrado em eletroduto pode apresentar uma queda de tens\u00e3o bem maior.<\/li>\n<li><strong>Comprimento em um s\u00f3 sentido.<\/strong> Informe a dist\u00e2ncia da fonte at\u00e9 a carga, n\u00e3o a ida e a volta. O fator 2 do circuito monof\u00e1sico j\u00e1 considera o condutor de retorno.<\/li>\n<li><strong>Trif\u00e1sico equilibrado.<\/strong> O fator \u221a3 assume correntes iguais nas tr\u00eas fases. Cargas muito desequilibradas exigem an\u00e1lise por fase.<\/li>\n<li><strong>Conex\u00f5es desconsideradas.<\/strong> Emendas, conex\u00f5es e terminais de dispositivos acrescentam uma pequena resist\u00eancia adicional que n\u00e3o est\u00e1 inclu\u00edda neste resultado.<\/li>\n<\/ul>\n<p>Dica pr\u00e1tica: se o resultado ultrapassar o limite de 3% do circuito ramificado, voc\u00ea pode encurtar o trecho, reduzir a corrente da carga ou passar para um condutor maior \u2014 verifique as bitolas rapidamente com nossa <a href=\"https:\/\/wpcalc.com\/pt\/engenharia\/bitola-de-fio-awg\/\">calculadora de bitola de fio<\/a>. Para relacionar a tens\u00e3o resultante, a corrente e a resist\u00eancia da carga, consulte a <a href=\"https:\/\/wpcalc.com\/en\/engineering\/ohms-law\/\">calculadora de Lei de Ohm<\/a>, ou use a <a href=\"https:\/\/wpcalc.com\/en\/engineering\/resistors-in-series\/\">calculadora de resistores em s\u00e9rie<\/a> para somar as resist\u00eancias do condutor e da carga em um circuito de corrente cont\u00ednua.<\/p>\n<h2>Valores t\u00edpicos de resistividade<\/h2>\n<table>\n<thead>\n<tr>\n<th>Material<\/th>\n<th>\u03c1 (\u03a9\u00b7mm\u00b2\/m a 20 \u00b0C)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Prata<\/td>\n<td>0,0159<\/td>\n<\/tr>\n<tr>\n<td>Cobre<\/td>\n<td>0,0172<\/td>\n<\/tr>\n<tr>\n<td>Alum\u00ednio<\/td>\n<td>0,0282<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>S\u00e3o os mesmos valores usados pela calculadora. Para ligas como lat\u00e3o ou niquel-cromo, selecione \"Resistividade personalizada\" e informe o valor do fabricante.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Calcule a queda de tens\u00e3o em um cabo de cobre, alum\u00ednio ou prata. Informe a corrente, a tens\u00e3o de alimenta\u00e7\u00e3o, o comprimento e a se\u00e7\u00e3o do condutor para obter a queda em volts, em porcentagem e a tens\u00e3o na carga.<\/p>\n","protected":false},"author":3168,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[6],"tags":[35],"class_list":["post-2104","post","type-post","status-publish","format-standard","hentry","category-engenharia","tag-eletrica"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/posts\/2104","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/users\/3168"}],"replies":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/comments?post=2104"}],"version-history":[{"count":0,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/posts\/2104\/revisions"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/media?parent=2104"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/categories?post=2104"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/tags?post=2104"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}