{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY8450-8BB08","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY8450-8BB08","canonicalUrl":"https://aoctrl.com/siemens/5SY8450-8BB08","factsUrl":"https://aoctrl.com/api/mcp/products/5SY8450-8BB08","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY8450-8BB08, miniature circuit breaker, 4-pole D-curve, 50 A rated, 400 V AC, 20 kA IEC 60947-2 breaking capacity.","salesMarkdown":"Mounts via quick assembly system to DIN rail — the 72 mm width occupies 4 width units. Combined terminals top and bottom accept solid or stranded conductors from 0.75 to 35 mm², torqued to 2.5–3.5 N·m. Sealable, halogen-free, silicon-free — relevant for clean-room or pharmaceutical GMP lines where material outgassing triggers a deviation. The 5SY8450-8BB08 is a 4-pole, 50 A D-curve unit. A common peer is the 5SY4140-7 — a 1-pole, 40 A B-curve MCB. The 5SY8450-8BB08 will not drop into a panel specified around the 5SY4140-7 without rewiring: different pole count, different width (4 units vs 1), different curve, and different terminal capacity. The 5SY8450-8BB08 is for a three-phase plus neutral circuit with a high-inrush load; the 5SY4140-7 is for a single-phase lighting or control circuit. No direct second-source relationship — they serve different protection profiles. Overvoltage category III — rated for fixed-installation distribution panels, not just downstream equipment. The magnetic-only tripping design means no thermal bimetal — the D-curve is purely electromagnetic, so ambient temperature does not shift the trip threshold the way a thermal-magnetic breaker would. The 5 kA rating under UL 1077 and CSA C22.2 No.235 covers North American supplementary protection applications; the 20 kA per IEC 60947-2 governs the European main-distribution SCCR declaration.","metaTitle":"Siemens 5SY8450-8BB08 SENTRON MCB, 4P D 50 A, 20 kA","metaDescription":"Siemens 5SY8450-8BB08 SENTRON miniature circuit breaker, 4-pole, D-curve, 50 A, 400 V AC, 20 kA IEC breaking capacity. Current lifecycle stage. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Miniature Circuit Breakers (MCB)"],"specifications":{"Depth":"76 mm","Solid":"0.75 ... 35 mm²","Width":"72 mm","Height":"90 mm","Sealable":"Yes","Stranded":"0.75 ... 35 mm²","Rated Value":"50/60 Hz","Halogen-Free":"Yes","Silicon-Free":"Yes","Mounting type":"Quick assembly system","During Storage":"-40 ... +75 °C","Number of poles":"4","Type of voltage":"AC","lifecycle_stage":"current","Mounting position":"any","Installation depth":"70 mm","Product brand name":"SENTRON","Ambient temperature":"-25 ... +45 °C","Product designation":"Miniature circuit breaker","Protection class IP":"IP20, with connected conductors","at AC / rated value":"400 V","Overvoltage category":"III","Combined Terminal Top":"Yes","Design of the product":"Only magnetic tripping operation","Number of width units":"4","Number of poles / Note":"4P","acc. to DIN EN 61346-2":"F","Combined Terminal Bottom":"Yes","Suitability for operation":"Mechanical engineering / industry","Current / at AC / rated value":"50 A","Tripping characteristic class":"D","at DC / rated value / maximum":"72 V","Position / of power supply cord":"Any","acc. to IEC 60947-2 / rated value":"20 kA","Product feature / Touch protection":"Yes","Influence of the surrounding temperature":"max. 95% to 55°C, max. 55% to 70°C, max. 35% to 75°C","at AC / acc. to UL 1077 and CSA C22.2 No.235":"5 kA","Tightening torque / with screw-type terminals":"2.5 ... 3.5 N·m","Product function / neutral conductor switching":"No","with multi-phase operation / at AC / rated value":"440 V","with single-phase operation / at AC / rated value":"440 V","Mechanical service life (switching cycles) / typical":"10 000","Tightening torque [lbf·in] / with screw-type terminals":"22 ... 31 lbf·in","AWG number / as coded connectable conductor cross section":"18 ... 4"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/d073081a6105089898129baa6bc44fa0.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=14540&mlfb=5SY8450-8BB08","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SY8450-8BB08/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy the 5SY8450-8BB08 and get a price?","answer":"Sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm commercial response."},{"question":"What is the closest functional second-source to the 5SY8450-8BB08?","answer":"No direct second-source exists. The 5SY4140-7 is a 1-pole, 40 A B-curve MCB — different pole count, curve, and current rating. The 5SY8450-8BB08 is a 4-pole D-curve 50 A unit; any substitution requires a full coordination review."},{"question":"What compliance documentation does the 5SY8450-8BB08 carry?","answer":"The part carries IEC 60947-2 (20 kA breaking capacity), UL 1077 and CSA C22.2 No.235 (5 kA supplementary protection), overvoltage category III, and IP20 protection class. It is halogen-free and silicon-free, supporting RoHS/REACH material compliance requirements."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY8450-8BB08","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/siemens/5SY8450-8BB08 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}