{"id":3544,"date":"2026-08-09T15:00:00","date_gmt":"2026-08-09T15:00:00","guid":{"rendered":"https:\/\/chac-electric.com\/blog\/mpcb-auxiliary-contact-panel-signals\/"},"modified":"2026-08-09T15:00:00","modified_gmt":"2026-08-09T15:00:00","slug":"mpcb-auxiliary-contact-panel-signals","status":"publish","type":"post","link":"https:\/\/chac-electric.com\/pt\/blog\/mpcb-auxiliary-contact-panel-signals\/","title":{"rendered":"How Should Panel Teams Specify an MPCB Auxiliary Contact?"},"content":{"rendered":"<div class=\"b2b-article\">\n<p style=\"margin:0 0 16px;line-height:1.7\"><strong>An MPCB auxiliary contact should be specified as a panel-signal interface, not assumed from a motor-protector family name.<\/strong> The drawing needs to identify the status or control signal required, the contact state, the intended interface, and the selected device\/accessory evidence. That information lets a supplier review the request without converting an undefined panel function into a generic product claim.<\/p>\n<figure style=\"margin:26px 0;text-align:center\"><img decoding=\"async\" style=\"max-width:640px;width:100%;height:auto;display:block;margin:0 auto;border-radius:8px\" src=\"https:\/\/chac-electric.com\/wp-content\/uploads\/2026\/06\/cqv2-me32-24-32a-1-0.webp\" alt=\"CHAC CQV2 motor protection circuit breaker for a panel signal review\"><\/figure>\n<nav class=\"b2b-toc\" style=\"background:#f5f8fa;padding:16px 20px;border-radius:8px;margin:0 0 24px\">\n<h2 id=\"contents\" style=\"margin:42px 0 14px;scroll-margin-top:96px\">Conte\u00fados<\/h2>\n<ul style=\"margin:0 0 18px 1.2em;line-height:1.7\">\n<li style=\"margin:0 0 8px\"><a href=\"#part-1-what-job-does-an-mpcb-auxiliary-contact-support\">Part 1. What job does an MPCB auxiliary contact support?<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#part-2-which-panel-signal-should-be-defined-before-sourcing\">Part 2. Which panel signal should be defined before sourcing?<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#part-3-how-should-the-contact-state-be-written-on-the-drawing\">Part 3. How should the contact state be written on the drawing?<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#part-4-what-must-be-checked-at-the-control-interface\">Part 4. What must be checked at the control interface?<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#part-5-which-details-belong-in-the-rfq\">Part 5. Which details belong in the RFQ?<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#part-6-where-is-the-fit-boundary-for-an-auxiliary-contact-request\">Part 6. Where is the fit boundary for an auxiliary-contact request?<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#part-7-which-chac-route-starts-the-product-discussion\">Part 7. Which CHAC route starts the product discussion?<\/a><\/li>\n<\/ul>\n<\/nav>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-1-what-job-does-an-mpcb-auxiliary-contact-support\">Part 1. What job does an MPCB auxiliary contact support?<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\">An auxiliary contact can provide a status or control interface associated with a motor-protection circuit-breaker arrangement when the selected device and accessory documentation support the requested function. It is therefore a panel-interface question, not a substitute for the main protection decision.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">Start by naming the information the panel needs to exchange. Examples may include a state indication, an interlock input, or a signal to another control element, but the final function must be written against the chosen design rather than inferred from a generic accessory description.<\/p>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-2-which-panel-signal-should-be-defined-before-sourcing\">Part 2. Which panel signal should be defined before sourcing?<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\">Write the required signal in terms the drawing team can verify: what event is reported, where the signal goes, and what should happen when the stated condition changes. This separates a useful status requirement from a vague request for \u201can auxiliary contact.\u201d<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">The request should also show whether the signal is for indication, logic, or an interface to another panel component. Those are different application questions, and each needs the selected model and the project control design to be checked.<\/p>\n<table style=\"width:100%;border-collapse:collapse\">\n<thead>\n<tr>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">Signal question<\/th>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">Why the answer matters<\/th>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">N\u00e3o assuma<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">What condition is reported?<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Defines the information needed by the panel<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">A generic accessory supplies every signal<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Where does the signal go?<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Identifies the interface to review<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Another device uses the same terminals<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">What action follows?<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Connects the signal to the control design<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">A status indication is a safety function<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Which device is proposed?<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Links the request to documentation<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Every MPCB variant accepts the same accessory<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-3-how-should-the-contact-state-be-written-on-the-drawing\">Part 3. How should the contact state be written on the drawing?<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\">Describe the required contact state and the condition it represents in the drawing notes. A simple \u201cauxiliary contact required\u201d label leaves the supplier and panel builder to guess whether the intended signal is normally open, normally closed, or tied to a particular device state.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">Terminal identification belongs with that request. The selected documentation should be used to confirm the actual terminal designations and any conditions that apply to the proposed accessory; do not copy terminal numbers from an unrelated product family.<\/p>\n<figure style=\"margin:26px 0;text-align:center\"><img decoding=\"async\" style=\"max-width:640px;width:100%;height:auto;display:block;margin:0 auto;border-radius:8px\" src=\"https:\/\/chac-electric.com\/wp-content\/uploads\/2026\/07\/CQV2-1.webp\" alt=\"Product identification graphic for a CHAC CQV2 motor protection circuit breaker\"><\/figure>\n<blockquote>\n<p style=\"margin:0 0 16px;line-height:1.7\"><strong>Importante:<\/strong> A status contact and a safety function are not interchangeable descriptions. Keep the required panel function, selected accessory documentation, and project control review aligned before the drawing is released. (<a href=\"https:\/\/www.iec.ch\/standardsdev\" rel=\"nofollow noopener\" target=\"_blank\">Panor\u00e2mica do desenvolvimento de normas da IEC<\/a>)<\/p>\n<\/blockquote>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-4-what-must-be-checked-at-the-control-interface\">Part 4. What must be checked at the control interface?<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\">The control-interface review should include the destination device, signal logic, available control supply, terminal access, and the documentation needed for the selected arrangement. That review prevents an accessory request from becoming disconnected from the rest of the panel design.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">At this stage, avoid representing an interface as confirmed solely because the product family has a matching mechanical form. The panel drawing, selected model, and accessory documents must agree before the interface is released for build.<\/p>\n<table style=\"width:100%;border-collapse:collapse\">\n<thead>\n<tr>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">Interface input<\/th>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">Why it changes the review<\/th>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">Evidence to request<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Required signal and logic<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Defines the contact function<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Control schematic<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Contact state<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Identifies the requested behavior<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Drawing note and selected documentation<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Destination device<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Defines the interface boundary<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">I\/O or control schedule<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Terminal and assembly constraints<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Checks the proposed installation<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Device\/accessory documentation<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-5-which-details-belong-in-the-rfq\">Part 5. Which details belong in the RFQ?<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\">The RFQ should identify the motor-protection device, required signal, contact state, control-interface destination, drawing revision, installation constraints, documentation request, and any project requirements that affect the panel build. This is enough context for a supplier to say which questions still need selected-model evidence.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">Ask for documentation that addresses the proposed device and accessory combination. If the exact contact function, terminal information, or compatibility is not documented for the stated configuration, keep it as an open technical item rather than assuming the accessory is included.<\/p>\n<table style=\"width:100%;border-collapse:collapse\">\n<thead>\n<tr>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">O comprador deve fornecer<\/th>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">Por que \u00e9 importante<\/th>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">Enviar com cita\u00e7\u00e3o<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Proposed MPCB and signal purpose<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Defines the product and function review<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Device reference and panel notes<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Contact state and logic<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Makes the requested interface explicit<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Control schematic<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Destination and control context<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Identifies the panel boundary<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">I\/O schedule<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Installation and assembly constraints<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Checks the proposed arrangement<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Layout or enclosure information<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Pedido de documenta\u00e7\u00e3o<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Makes the supplier response auditable<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Selected-model and accessory documents<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p style=\"margin:0 0 16px;line-height:1.7\">For adjacent motor-protection context, read the <a href=\"https:\/\/chac-electric.com\/pt\/blogue\/mpcb-vs-mccb-motor-protection-boundary\/\">MPCB versus MCCB boundary guide<\/a> and the <a href=\"https:\/\/chac-electric.com\/pt\/blogue\/motor-protection-circuit-breaker-contactor-coordination\/\">motor protection breaker and contactor coordination guide<\/a>. Neither article confirms an auxiliary-contact configuration for an unreviewed device.<\/p>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-6-where-is-the-fit-boundary-for-an-auxiliary-contact-request\">Part 6. Where is the fit boundary for an auxiliary-contact request?<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\">This article supports the early drawing and RFQ stage. It is not a safety-function design, a final wiring method, a local-code interpretation, or a field-modification procedure.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">If the panel function or selected device\/accessory data is incomplete, stop at the evidence gap. The right next step is to obtain the relevant project information and selected-model documentation before the accessory is approved for the panel.<\/p>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-7-which-chac-route-starts-the-product-discussion\">Part 7. Which CHAC route starts the product discussion?<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\">Begin with the <a href=\"https:\/\/chac-electric.com\/pt\/motor-protector\/\">motor-protector category<\/a> once the signal requirement is documented. The <a href=\"https:\/\/chac-electric.com\/pt\/product\/cqv2-series-motor-protection-circuit-breaker\/\">CHAC CQV2 motor protection circuit breaker product page<\/a> provides the first-party product route for a selected-model discussion, not confirmation that a particular auxiliary contact is supplied or suitable.<\/p>\n<figure style=\"margin:26px 0;text-align:center\"><img decoding=\"async\" style=\"max-width:640px;width:100%;height:auto;display:block;margin:0 auto;border-radius:8px\" src=\"https:\/\/chac-electric.com\/wp-content\/uploads\/2026\/07\/CQV2-5.webp\" alt=\"Dimensional drawing of a CHAC CQV2 motor protection circuit breaker\"><\/figure>\n<h3 style=\"margin:28px 0 12px\">Recomenda\u00e7\u00e3o de produto<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">After the RFQ records the device, signal purpose, contact state, control interface, drawing, and documentation request, use <a href=\"https:\/\/chac-electric.com\/pt\/personalizacao-de-controlo-industrial\/\">personaliza\u00e7\u00e3o de controlo industrial<\/a> ou <a href=\"https:\/\/chac-electric.com\/pt\/contacte-nos\/\">contactar CHAC Electric<\/a> for the product-document review. Do not substitute a generic contactor accessory or an unverified motor protector for the selected device\/accessory check.<\/p>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"faqs\">FAQs<\/h2>\n<h3 style=\"margin:28px 0 12px\">What does an auxiliary contact do on an MPCB?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">It can support a documented status or control interface associated with the selected motor-protection arrangement.<\/p>\n<h3 style=\"margin:28px 0 12px\">Is an auxiliary contact included with every MPCB?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">Do not assume it is included. Confirm the selected device and accessory documentation for the proposed configuration.<\/p>\n<h3 style=\"margin:28px 0 12px\">Which signal should be written on the drawing?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">State the event to be reported, where the signal goes, and the action or indication the panel requires.<\/p>\n<h3 style=\"margin:28px 0 12px\">How should NO and NC be requested?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">Write the required contact state and the condition it represents, then confirm terminal details in the selected documentation.<\/p>\n<h3 style=\"margin:28px 0 12px\">What belongs in the RFQ?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">Provide the proposed device, signal purpose, contact state, control interface, drawing revision, installation constraints, and documentation request.<\/p>\n<h3 style=\"margin:28px 0 12px\">What is outside this article?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">It does not replace safety-function design, final wiring instructions, local approval, or selected-model accessory verification.<\/p>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"references\">Refer\u00eancias<\/h2>\n<ul style=\"margin:0 0 18px 1.2em;line-height:1.7\">\n<li style=\"margin:0 0 8px\"><a href=\"https:\/\/webstore.iec.ch\/\" rel=\"nofollow noopener\" target=\"_blank\">IEC Loja Online<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"https:\/\/www.iec.ch\/standardsdev\" rel=\"nofollow noopener\" target=\"_blank\">Panor\u00e2mica do desenvolvimento de normas da IEC<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"https:\/\/support.industry.siemens.com\/\" rel=\"nofollow noopener\" target=\"_blank\">Siemens Industry Online Support<\/a><\/li>\n<\/ul>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>An MPCB auxiliary contact should be specified as a panel-signal interface, not assumed from a motor-protector family name. The drawing needs to identify the status or control signal required, the contact state, the intended interface, and the selected device\/accessory evidence. That information lets a supplier review the request without converting an undefined panel function into [&hellip;]<\/p>\n","protected":false},"author":10,"featured_media":973,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-3544","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":7}},"acf":[],"_links":{"self":[{"href":"https:\/\/chac-electric.com\/pt\/wp-json\/wp\/v2\/posts\/3544","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/chac-electric.com\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chac-electric.com\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chac-electric.com\/pt\/wp-json\/wp\/v2\/users\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/chac-electric.com\/pt\/wp-json\/wp\/v2\/comments?post=3544"}],"version-history":[{"count":0,"href":"https:\/\/chac-electric.com\/pt\/wp-json\/wp\/v2\/posts\/3544\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/chac-electric.com\/pt\/wp-json\/wp\/v2\/media\/973"}],"wp:attachment":[{"href":"https:\/\/chac-electric.com\/pt\/wp-json\/wp\/v2\/media?parent=3544"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chac-electric.com\/pt\/wp-json\/wp\/v2\/categories?post=3544"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chac-electric.com\/pt\/wp-json\/wp\/v2\/tags?post=3544"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}