{"product_id":"square-d-mjl36400-400a-600v-3-pole-circuit-breaker","title":"Square D MJL36400 - 400 A, 600 V, 3-Pole Circuit Breaker | AmpState","description":"\u003cdiv\u003e\n\u003cp\u003eEngineered for dependable branch circuit protection, the Square D MJL36400 is a 400 A, 600 V, 3-pole molded case circuit breaker designed to guard panelboards and loadcenters against overcurrent and short circuits. Its compact molded-case form frees up valuable space in crowded electrical panels while delivering precise, repeatable performance when protection is needed most.\u003c\/p\u003e \u003ch3\u003eWhy this breakers stands out\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003e\n\u003cstrong\u003eSpace-efficient molded-case design\u003c\/strong\u003e maximizes panel capacity, making room for future circuit additions without compromising protection.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eThermal-magnetic trip unit\u003c\/strong\u003e provides stable, repeatable protection by responding to both overload and short-circuit conditions with fast, predictable trips.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eThree-pole configuration\u003c\/strong\u003e ideal for 3-phase systems common in commercial and light industrial environments, while still suitable for residential panel setups that require robust protection.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eOEM compatibility\u003c\/strong\u003e engineered to be compatible with matching Square D loadcenters and panelboards, ensuring a reliable fit and straightforward replacement or upgrade.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eVersatile application\u003c\/strong\u003e suitable for residential, commercial, and light industrial protection scenarios where steady, dependable performance matters.\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 MJL36400\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Thermal-magnetic molded case circuit breaker (MCCB)\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eAmperage rating:\u003c\/strong\u003e 400 A\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eVoltage rating:\u003c\/strong\u003e 600 V\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003ePoles:\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\u003eIdeal use cases\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003eUpgrading or replacing protection in commercial panelboards and loadcenters that serve heavy equipment or multiple high-load circuits.\u003c\/li\u003e \u003cli\u003eFeeding 3-phase equipment in light industrial settings where reliable short-circuit protection is critical.\u003c\/li\u003e \u003cli\u003eInstalling as a dedicated feeder breaker for main distribution panels in mid-size facilities, helping to prevent nuisance trips and maintain uptime.\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003eHow it delivers real value\u003c\/h3\u003e\n\u003cp\u003eThe MJL36400 isn’t just a spec sheet entry—it’s a practical solution for engineers and electricians who demand predictable protection and panel efficiency. By combining a compact footprint with a dependable thermal-magnetic trip mechanism, this breaker protects valuable equipment while preserving panel space for future expansion. Its OEM compatibility means fewer compatibility concerns during installation, reducing the risk of misfits or incongruent trip curves.\u003c\/p\u003e \u003ch3\u003ePractical tips for installation and care\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003eVerify compatibility with your specific Square D loadcenter or panelboard model to ensure a seamless fit and correct bus alignment.\u003c\/li\u003e \u003cli\u003eUse in applications where 3-phase protection is required or where three-pole coverage is essential for balanced circuit protection.\u003c\/li\u003e \u003cli\u003eSchedule periodic visual inspections for signs of overheating or wear in the panel enclosure, and confirm that wiring terminations are tight to maintain reliable trips.\u003c\/li\u003e \u003cli\u003eKeep spare replacement units on hand for quick maintenance or capacity upgrades to minimize downtime.\u003c\/li\u003e\n\u003c\/ul\u003e \u003cp\u003eWhether you’re upgrading an aging panel, designing a new electrical room for a light industrial environment, or provisioning a commercial panelboard for higher load demands, the Square D MJL36400 400 A, 600 V, 3-Pole Circuit Breaker delivers targeted protection with space-conscious design and dependable performance. Add it to your panel today to ensure robust, long-lasting circuit protection that aligns with your Square D ecosystem and installation standards.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Amp State","offers":[{"title":"Default Title","offer_id":46355348717730,"sku":null,"price":710.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0666\/8094\/6850\/files\/schnieder_and_square_d_breaker_and_panel_581a9e6a-fc21-4e1c-a025-3eff0ab74b9e.png?v=1764691466","url":"https:\/\/www.ampstate.com\/products\/square-d-mjl36400-400a-600v-3-pole-circuit-breaker","provider":"Ampstate Electric Corporation","version":"1.0","type":"link"}