{"product_id":"square-d-a1b390-circuit-breaker","title":"Square D | A1B390 | Circuit Breaker | 3-Pole","description":"\u003cdiv\u003e\n\u003cp\u003eIntroducing the Square D A1B390 Circuit Breaker, a purpose-built 3-pole unit designed for robust protection in electrical panels where reliability and precise specs matter. Ideal for maintenance, retrofit, or replacement projects, this breaker brings proven Square D performance to your 3-phase circuits.\u003c\/p\u003e \u003cp\u003eKey considerations to guarantee a perfect match:\u003c\/p\u003e \u003cul\u003e \u003cli\u003e\n\u003cstrong\u003e3-Pole design\u003c\/strong\u003e: Provides synchronized disconnection of all three electrical legs, enhancing safety and control in 3-phase systems.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003ePart number A1B390\u003c\/strong\u003e: The most reliable reference for compatibility with Square D panels and enclosures. Use the part number to verify fit against your panel schedule.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eFit and ratings\u003c\/strong\u003e: Confirm the breaker’s amp rating, interrupting capacity, and frame type against your panel’s requirements before ordering.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eMaintenance, retrofit, and replacement\u003c\/strong\u003e: A1B390 is purpose-built for upgrading older installations or replacing worn breakers without changing the panel hardware.\u003c\/li\u003e\n\u003c\/ul\u003e \u003cp\u003eUse cases where this 3-pole breaker shines:\u003c\/p\u003e \u003cul\u003e \u003cli\u003eUpgrading or replacing 3-phase protection in manufacturing lines, HVAC systems, or data-center infrastructure.\u003c\/li\u003e \u003cli\u003eRetrofits in legacy Square D panels where a direct A1B390 replacement is specified on the panel schedule.\u003c\/li\u003e \u003cli\u003eMaintenance cycles that require predictable, fast-disconnect safety and clear trip behavior for all phases.\u003c\/li\u003e\n\u003c\/ul\u003e \u003cp\u003eWhy choose this Square D breaker over generic options? It’s engineered to match Square D’s electrical characteristics and mounting standards, reducing the risk of fit issues and ensuring reliable trip performance when your panel demands a 3-pole protection device.\u003c\/p\u003e \u003cp\u003ePractical installation and best-practice tips:\u003c\/p\u003e \u003cul\u003e \u003cli\u003eCross-check the panel’s labeling or wiring diagram for the exact trip curve and amp rating required.\u003c\/li\u003e \u003cli\u003eHave the panel’s bus connectors and mounting hardware inspected; even a slight mismatch can affect performance.\u003c\/li\u003e \u003cli\u003eKeep a record of the part number A1B390 for future maintenance or warranty inquiries.\u003c\/li\u003e\n\u003c\/ul\u003e \u003cp\u003eWhat you’ll receive with this order: a genuine Square D 3-pole circuit breaker identified by the A1B390 part number, ready to slot into compatible Square D panels—subject to the stated fit and rating confirmation.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Square D","offers":[{"title":"Default Title","offer_id":46424821366946,"sku":"A1B390","price":310.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0666\/8094\/6850\/files\/master_generic_a085eff1-75dd-47ee-b131-4c8df8f0489b.png?v=1765492976","url":"https:\/\/www.ampstate.com\/products\/square-d-a1b390-circuit-breaker","provider":"Ampstate Electric Corporation","version":"1.0","type":"link"}