{"product_id":"siemens-q21540ctnc-40a-240v-plug-in-circuit-breaker","title":"Siemens Q21540CTNC - 40 A, 240 V Plug-In Circuit Breaker | AmpState","description":"\u003cdiv\u003eSiemens Q21540CTNC 40A, 240V plug-in molded case circuit breaker delivers fast, reliable protection for your electrical panel while simplifying installation and maintenance. Engineered for dependable branch circuit overcurrent and short-circuit protection, this breaker is a purpose-built fit for Siemens panelboards and loadcenters, ensuring seamless compatibility and consistent performance. Key features that set this breaker apart\n\u003cul\u003e \u003cli\u003e\n\u003cstrong\u003eFast plug-in connection\u003c\/strong\u003e for quick installation and hassle-free replacement, reducing downtime during upgrades or service calls.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eThermal-magnetic trip unit\u003c\/strong\u003e provides stable, repeatable protection against both overloads and short circuits, helping safeguard downstream wiring and equipment.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eOEM compatibility\u003c\/strong\u003e designed to match Siemens loadcenters and panelboards, promoting reliable form-fit, electrical contact, and compliant operation.\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eVersatile applications\u003c\/strong\u003e suitable for residential, commercial, and light industrial environments where dependable branch circuit protection matters.\u003c\/li\u003e\n\u003c\/ul\u003e What this means for your electrical system\n\u003cp\u003eThe Q21540CTNC is purpose-built to protect a single branch circuit with a \u003cstrong\u003e40-amp\u003c\/strong\u003e rating at \u003cstrong\u003e240 volts\u003c\/strong\u003e. Its plug-in mounting style simplifies panel servicing—you can swap in a new breaker without rewiring or screw-terminal adjustments. The thermal-magnetic trip unit ensures precise trip characteristics, so you won’t have to guess whether a nuisance trip is coming from an overload or a genuine fault.\u003c\/p\u003e Use cases and ideal scenarios\n\u003cul\u003e \u003cli\u003eReplacing a worn or failed breaker in existing Siemens panelboards or loadcenters without compatibility concerns.\u003c\/li\u003e \u003cli\u003eUpgrading a branch circuit to the right protection level for high-draw appliances or equipment that require a dedicated 40A circuit.\u003c\/li\u003e \u003cli\u003eNew installations in residential, commercial, or light industrial spaces where reliable overcurrent protection is critical.\u003c\/li\u003e\n\u003c\/ul\u003e Technical snapshot\n\u003cul\u003e \u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Siemens\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e Q21540CTNC\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 40A\u003c\/li\u003e \u003cstrong\u003e\u003cli\u003eVoltage Rating:\u003c\/li\u003e\u003c\/strong\u003e 240V \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 Why choose this breaker over generic alternatives\n\u003cp\u003eChoosing a Siemens Q21540CTNC means selecting a plug-in breaker that is specifically engineered to work with Siemens panelboards and loadcenters, minimizing compatibility concerns and maximizing reliability. The combination of a plug-in connection, a stable thermal-magnetic trip mechanism, and OEM-aligned design translates to quicker service, fewer false trips, and long-term confidence in your electrical system.\u003c\/p\u003e Who benefits most\n\u003cul\u003e \u003cli\u003eElectricians performing panel upgrades, replacements, or routine maintenance in homes, offices, retail spaces, and light manufacturing.\u003c\/li\u003e \u003cli\u003eFacilities managers seeking dependable, code-consistent protection for critical circuits without complex installations.\u003c\/li\u003e \u003cli\u003eDIY enthusiasts working on compatible Siemens panels who want a precise, plug-in solution that’s ready to install.\u003c\/li\u003e\n\u003c\/ul\u003e Additional considerations and practical tips\n\u003cp\u003eBefore installation, confirm that the replacement part number matches your panel’s requirements and that the overall system rating aligns with your electrical design. Use a compatible panelboard or loadcenter from Siemens to ensure optimal contact quality and trip accuracy. Label the circuit clearly after installation to help future service efforts and inspections run smoothly.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Amp State","offers":[{"title":"Default Title","offer_id":46355155124386,"sku":null,"price":710.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0666\/8094\/6850\/files\/siemens-q21540ctnc-40-a-240-v-plug-in-circuit-breaker-ampstate-713.webp?v=1788735775","url":"https:\/\/www.ampstate.com\/products\/siemens-q21540ctnc-40a-240v-plug-in-circuit-breaker","provider":"Ampstate Electric Corporation","version":"1.0","type":"link"}