{"product_id":"siemens-e21b040","title":"Siemens E21B040 40A 1-Pole 120 V Circuit Breaker","description":"\u003cdiv\u003e\n\u003cp\u003eMeet the Siemens E21B040 40A 1-Pole 120V Circuit Breaker — a dependable, single-pole protective device designed to guard a dedicated 120-volt circuit in your residential panel. This Siemens circuit breaker (part number E21B040) delivers reliable overcurrent protection, helping prevent wiring damage and electrical hazards by interrupting fault currents when needed.\u003c\/p\u003e \u003cp\u003eKey specs at a glance\u003c\/p\u003e \u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCurrent rating:\u003c\/strong\u003e 40 A\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePoles:\u003c\/strong\u003e 1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVoltage rating:\u003c\/strong\u003e 120 V\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart number:\u003c\/strong\u003e E21B040\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Siemens\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003eWhy this 40A, 1-Pole 120V breaker could be the right choice\u003c\/h3\u003e \u003cp\u003eThis breaker is tailored for residential electrical panels that accommodate Siemens breakers. It provides targeted protection for a high-draw 120V circuit, allowing you to run equipment or outlets that demand more current without compromising the overall panel safety. The 40-amp rating means it’s designed for heavier loads than standard 15A or 20A circuits, while still delivering reliable interruption to protect conductors and connected devices.\u003c\/p\u003e \u003ch3\u003eWhat makes it stand out\u003c\/h3\u003e \u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecise current protection:\u003c\/strong\u003e A 40 A rating ensures controlled response to overloads on heavy-duty 120V branches, helping prevent overheating and electrical fires.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSeamless Siemens integration:\u003c\/strong\u003e Built to fit Siemens panels and enclosures that support E-series breakers, making upgrades or replacements straightforward.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSingle-pole convenience:\u003c\/strong\u003e Ideal for dedicated 120V circuits where a single-pole protection is appropriate.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eClear part identification:\u003c\/strong\u003e Part number E21B040 for accurate ordering and verification within your electrical system.\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003eIdeal use cases\u003c\/h3\u003e \u003cp\u003eConsider this Siemens breaker when you need to protect a dedicated 120V circuit with higher current capacity. It’s well-suited for:\u003c\/p\u003e \u003cul\u003e\n\u003cli\u003eHome workshops powering high-draw tools or air compressors on a single 120V branch\u003c\/li\u003e\n\u003cli\u003eDedicated circuits for garage or utility room outlets housing larger appliances\u003c\/li\u003e\n\u003cli\u003eUpgrading an existing Siemens panel where a 40A, 1-pole protection is appropriate\u003c\/li\u003e\n\u003c\/ul\u003e \u003cp\u003eNote: Always ensure compliance with local electrical codes and have a qualified professional handle installation. Verify that your panel accepts E21B040 breakers before replacement or installation.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Siemens","offers":[{"title":"Default Title","offer_id":46423271800994,"sku":"E21B040","price":510.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0666\/8094\/6850\/files\/master_generic_229276d9-908d-46df-93e5-6fe31866e0ff.png?v=1765492975","url":"https:\/\/www.ampstate.com\/products\/siemens-e21b040","provider":"Ampstate Electric Corporation","version":"1.0","type":"link"}