{"product_id":"square-d-mgl36400-400a-600v-3-pole-circuit-breaker","title":"Square D MGL36400 - 400 A, 600 V, 3-Pole Circuit Breaker | AmpState","description":"\u003cdiv\u003e\n\u003cp\u003eThe Square D MGL36400 is a 400A, 600V, 3-pole molded case circuit breaker designed to deliver dependable branch circuit protection in panelboards and loadcenters. Built for consistent performance in commercial, residential, and light industrial environments, this MCCB combines a compact footprint with robust protection for three‑phase feeders and distribution circuits.\u003c\/p\u003e \u003ch3\u003eWhat makes this breaker stand out\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003e\n\u003cstrong\u003eCompact molded-case design\u003c\/strong\u003e prioritizes panel space efficiency, making installation cleaner and allowing room for additional circuits in tight panels.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eThermal-magnetic trip unit\u003c\/strong\u003e delivers stable, repeatable protection against both overloads and short circuits across varying loads and ambient conditions.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003e3-pole configuration\u003c\/strong\u003e ideal for 3-phase systems, providing coordinated protection for all phases and ensuring reliable shutdowns in fault conditions.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003e400A rating at 600V\u003c\/strong\u003e suits main or feeder protection in medium to large commercial panels and light industrial applications, balancing capacity with space efficiency.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eOEM compatibility\u003c\/strong\u003e designed to work with matching Square D MGL panelboards and loadcenters, streamlining replacements and upgrades without sacrificing performance.\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003eWhere you’ll use it\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003eMain protection in commercial panelboards and light industrial distribution centers\u003c\/li\u003e \u003cli\u003eFeeder protection for critical equipment and three-phase machinery\u003c\/li\u003e \u003cli\u003ePanel upgrades or replacements in renov projects where space is at a premium\u003c\/li\u003e \u003cli\u003eResidential-commercial hybrids where a robust 3-phase protection solution is needed\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003eTechnical snapshot\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Square D\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003ePart number:\u003c\/strong\u003e MGL36400\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Thermal-magnetic molded case circuit breaker\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eAmperage rating:\u003c\/strong\u003e 400A\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eVoltage rating:\u003c\/strong\u003e 600V\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eNumber of poles:\u003c\/strong\u003e 3\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Branch circuit overcurrent and short-circuit protection\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003eWhy it matters for your system\u003c\/h3\u003e\n\u003cp\u003eProtection isn’t just about shutting off when things go wrong—it’s about precise, predictable response that minimizes downtime and risk. The MGL36400’s thermal-magnetic trip unit provides clear, reliable protection against overloads and instantaneous short-circuit trips, helping to safeguard wiring, feeders, and connected equipment. Its compatibility with Square D MGL panelboards means you can upgrade or expand with confidence, preserving system performance and reducing retrofit complexity.\u003c\/p\u003e \u003ch3\u003eInstallation and care tips\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003eInstall by a qualified electrician in accordance with local electrical codes and the National Electrical Code (NEC) requirements.\u003c\/li\u003e \u003cli\u003eEnsure the panelboard or loadcenter supports 3-pole 400A devices of the MGL series for proper fit and rated performance.\u003c\/li\u003e \u003cli\u003eInspect connections for tightness during installation to maintain optimal voltage drop and reliability.\u003c\/li\u003e \u003cli\u003eKeep the environment within the panel using standard cooling practices; a cooler, well-ventilated enclosure supports better breaker performance over time.\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003ePractical takeaways\u003c\/h3\u003e\n\u003cp\u003eIf you’re upgrading a panel to support higher loads or reorganizing a three-phase distribution, the Square D MGL36400 provides a compact, reliable 400A main\/feeder protection solution that aligns with Square D MGL hardware. Its 600V rating covers a wide range of commercial and light industrial circuits, while the 3-pole design ensures synchronized protection across all phases. For installers and facility managers, it’s a straightforward, compatible choice that minimizes panel rearrangement and simplifies ongoing maintenance.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Amp State","offers":[{"title":"Default Title","offer_id":46355345014946,"sku":null,"price":710.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0666\/8094\/6850\/files\/square-d-mgl36400-400-a-600-v-3-pole-circuit-breaker-ampstate-877.webp?v=1788751309","url":"https:\/\/www.ampstate.com\/products\/square-d-mgl36400-400a-600v-3-pole-circuit-breaker","provider":"Ampstate Electric Corporation","version":"1.0","type":"link"}