{"product_id":"square-d-qo340-40a-240v-3-pole-plug-in-circuit-breaker","title":"Square D QO340 - 40 A, 240 V, 3-Pole Plug-In Circuit Breaker | AmpState","description":"\u003cdiv\u003e\n\u003cp\u003eMeet dependable, site-ready protection for your electrical backbone with the Square D QO340 — a 40 A, 240 V, 3-pole plug-in circuit breaker designed for fast, reliable protection in panelboards and load centers. Built to simplify maintenance and reduce downtime, this molded case breaker delivers precise, repeatable protection for demanding residential, commercial, and light industrial circuits.\u003c\/p\u003e \u003ch3\u003eWhy this breaker stands out\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003e\n\u003cstrong\u003eFast plug-in connection:\u003c\/strong\u003e A streamlined plug-in design speeds installation and simplifies replacement, so downtime is minimized during service or upgrades.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eThermal-magnetic trip unit:\u003c\/strong\u003e The combination of a thermal element for overload protection and a magnetic trip for short circuits provides stable, repeatable protection performance across varying loads and conditions.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003e3-pole, 240 V configuration:\u003c\/strong\u003e Ideal for 3-phase panelboards and 240 V feeders, enabling safe, coordinated protection for larger or multi-wire circuits.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eOEM-compatible:\u003c\/strong\u003e Specifically designed to pair with matching Square D OEM load centers and panelboards, ensuring consistent performance and straightforward compatibility during panel upgrades or maintenance.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eMolded case, plug-in design:\u003c\/strong\u003e Durable construction with a clean, tool-free connection that reduces wiring errors and simplifies field service.\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003eWho benefits most\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003eElectrical contractors and maintenance techs working on residential service upgrades, light commercial installations, or small industrial feeders.\u003c\/li\u003e \u003cli\u003eProjects requiring reliable 40 A protection on 240 V multi-wire or three-phase circuits, where quick swap-in replacement minimizes downtime.\u003c\/li\u003e \u003cli\u003ePanels that demand easy compatibility with OEM load centers and straightforward, plug-in installation.\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003ePractical applications and use cases\u003c\/h3\u003e\n\u003cp\u003eUse the QO340 to protect branch circuits in panelboards and load centers where a 40 A, 240 V, 3-pole plug-in breaker is appropriate. It’s well-suited for 3-phase motor circuits, large lighting feeders, or other 240 V equipment in light commercial settings, as well as residential environments with multi-wire branch circuits that require coordinated protection.\u003c\/p\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 QO340\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 40 A\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eVoltage Rating:\u003c\/strong\u003e 240 V\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eNumber of Poles:\u003c\/strong\u003e 3\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eMounting Style:\u003c\/strong\u003e Plug-in\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\u003eTips for maximizing performance\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003eEnsure your panelboard is rated for QO-series plug-in breakers to maintain system coordination and warranty integrity.\u003c\/li\u003e \u003cli\u003ePlan circuit layouts with the 3-pole configuration in mind for balanced power distribution in three-phase or multi-wire setups.\u003c\/li\u003e \u003cli\u003eDuring service, use the plug-in design to minimize downtime and simplify future replacements or upgrades.\u003c\/li\u003e \u003cli\u003ePair with compatible OEM components to maintain consistent trip curves and protection characteristics across the entire panel.\u003c\/li\u003e\n\u003c\/ul\u003e \u003cp\u003eExplore reliable, factory-backed protection with the Square D QO340 40 A, 240 V, 3-Pole Plug-In Circuit Breaker from AmpState — built to safeguard your circuits while keeping installation straightforward and maintenance manageable.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Amp State","offers":[{"title":"Default Title","offer_id":46355404980386,"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_834f3425-7a03-45e1-ac0f-1cfd08fc7937.png?v=1764691865","url":"https:\/\/www.ampstate.com\/products\/square-d-qo340-40a-240v-3-pole-plug-in-circuit-breaker","provider":"Ampstate Electric Corporation","version":"1.0","type":"link"}