{"id":215132,"date":"2025-05-16T10:17:09","date_gmt":"2025-05-16T10:17:09","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=215132"},"modified":"2025-05-16T10:17:11","modified_gmt":"2025-05-16T10:17:11","slug":"a-multiwire-branch-circuit-can-supply","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/16\/a-multiwire-branch-circuit-can-supply\/","title":{"rendered":"A multiwire branch circuit can supply"},"content":{"rendered":"\n<p>A multiwire branch circuit can supply:<\/p>\n\n\n\n<p>I. 120\/240 volts to only one piece of utilization equipment<\/p>\n\n\n\n<p>II. 120\/240 volts where all ungrounded conductors are opened simultaneously<\/p>\n\n\n\n<p>a) I only<br>b) II only<br>c) either I or II<br>d) neither I nor II<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-1-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>The correct answer is:<br><strong>b) II only<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation:<\/h3>\n\n\n\n<p>A <strong>multiwire branch circuit<\/strong> (MWBC) is a wiring method used in electrical systems where two or more ungrounded (hot) conductors share a common neutral conductor. These circuits typically provide <strong>120\/240 volts<\/strong> in residential and commercial settings.<\/p>\n\n\n\n<p>Let\u2019s analyze the two statements:<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>I. &#8220;120\/240 volts to only one piece of utilization equipment&#8221;<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>This statement is <strong>incorrect<\/strong> for a multiwire branch circuit.<\/li>\n\n\n\n<li>An MWBC typically serves <strong>multiple loads or utilization equipment<\/strong>, not just one.<\/li>\n\n\n\n<li>The circuit contains two or more hot wires (ungrounded conductors) and a shared neutral, allowing simultaneous supply of multiple devices or loads at 120 volts from each hot conductor to neutral, or 240 volts across the two hots.<\/li>\n\n\n\n<li>Although it could theoretically supply one large 240V load, MWBCs are generally designed to supply <strong>more than one utilization equipment<\/strong> (e.g., multiple outlets or appliances on different branches).<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>II. &#8220;120\/240 volts where all ungrounded conductors are opened simultaneously&#8221;<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>This statement is <strong>correct<\/strong> and reflects a critical safety feature of MWBCs.<\/li>\n\n\n\n<li>The <strong>National Electrical Code (NEC)<\/strong> requires that all ungrounded conductors of a multiwire branch circuit be opened simultaneously by a <strong>common disconnect<\/strong> or a <strong>two-pole circuit breaker<\/strong>.<\/li>\n\n\n\n<li>This ensures that when the circuit is turned off, <strong>all hot conductors<\/strong> are de-energized, preventing potential shock hazards or damage when servicing or working on the circuit.<\/li>\n\n\n\n<li>Because the two or more ungrounded conductors share a neutral, if only one conductor were opened while the others remained live, the neutral could carry unexpected current, creating dangerous conditions.<\/li>\n\n\n\n<li>By opening all ungrounded conductors simultaneously, the circuit ensures complete disconnection of power for safety.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Additional details:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>A multiwire branch circuit generally consists of two hot wires (often on different phases of a 240V supply) and one neutral wire.<\/li>\n\n\n\n<li>Each hot wire supplies 120 volts to its own load, but the loads share a neutral.<\/li>\n\n\n\n<li>When loads on both hots operate simultaneously, the neutral current is the <strong>difference<\/strong> of the currents on the two hot wires, rather than their sum, reducing the neutral conductor size requirement.<\/li>\n\n\n\n<li>The <strong>shared neutral<\/strong> concept and the simultaneous disconnection are key safety features unique to MWBCs.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Summary:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Statement I is <strong>false<\/strong> because MWBCs supply multiple loads, not just one piece of equipment.<\/li>\n\n\n\n<li>Statement II is <strong>true<\/strong> and critical for safe operation.<\/li>\n\n\n\n<li>Therefore, the answer is <strong>b) II only<\/strong>.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>A multiwire branch circuit can supply: I. 120\/240 volts to only one piece of utilization equipment II. 120\/240 volts where all ungrounded conductors are opened simultaneously a) I onlyb) II onlyc) either I or IId) neither I nor II The Correct Answer and Explanation is: The correct answer is:b) II only Explanation: A multiwire branch [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center 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