{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY8401-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY8401-8","canonicalUrl":"https://aoctrl.com/siemens/5SY8401-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SY8401-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON miniature circuit breaker, 5SY8401-8, 4-pole D-characteristic, 1 A rated current AC, 70 kA breaking capacity per IEC 60947-2.","salesMarkdown":"## What this 4-pole D-curve MCB delivers in a dusty, hot panel The Siemens SENTRON 5SY8401-8 is a 4-pole miniature circuit breaker with a D tripping characteristic, rated at 1 A AC and 70 kA breaking capacity per IEC 60947-2. Rated for the heat, not the office: it's certified for -40 °C to 75 °C ambient, and the current derates to 0.98 A at 50 °C and 0.95 A at 55 °C — so if your panel runs hot, you don't lose the branch. ## Mounting and integration — 4 MW units, any position Mounting position is any, so you can lay it sideways in a shallow gland plate if needed. Combined terminal top and bottom accepts busbars or ring lugs; the sealable cover keeps operators from toggling the handle without authorization. ## Breaking capacity and compliance — the numbers that matter for coordination The 70 kA at AC per IEC 60947-2 is the headline — that's the ultimate short-circuit breaking capacity at 400 V, giving you headroom for high-fault installations. For DC circuits, it's rated 15 kA per the same standard. If you're exporting to North America, note the UL 1077 / CSA C22.2 No.235 rating is 5 kA at AC — that's the supplementary protector rating, not the branch-circuit rating. Vibration resistance per IEC 60068-2-6 (±1 mm at 5-25 Hz, 50 m/s² at 25-150 Hz) means it holds up on a conveyor drive panel or near a kiln shell.","metaTitle":"Siemens 5SY8401-8 SENTRON MCB, 4P D-curve 1A, 70kA","metaDescription":"Siemens SENTRON 5SY8401-8 miniature circuit breaker, 4-pole D-curve rated 1 A AC, 70 kA breaking capacity per IEC 60947-2. Active production, 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","Width":"72 mm","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","Halogen-Free":"Yes","Silicon-Free":"Yes","Number Of Poles":"4","Type Of Voltage":"AC","lifecycle_stage":"current","Fastening Method":"Quick assembly system","Mounting Position":"any","Installation Depth":"70 mm","Product Brand Name":"SENTRON","Degree Of Pollution":"3","Product Designation":"Miniature circuit breaker","acc. to IEC 81346-2":"F","at AC / rated value":"1 A","protection class IP":"IP20, with connected conductors","Overvoltage Category":"III","Combined Terminal Top":"Yes","Number Of Poles / Note":"4P","acc. to DIN EN 61346-2":"F","at 45 °C / rated value":"1 A","at 50 °C / rated value":"0.98 A","at 55 °C / rated value":"0.95 A","Combined Terminal Bottom":"Yes","Suitability For Operation":"Mechanical engineering / industry","Number Of Modular Width Units":"4","Tripping Characteristic Class":"D","Position / Of Power Supply Cord":"Any","acc. to IEC 60947-2 / rated value":"70 kA","Product Feature / Touch Protection":"Yes","Supply Voltage Frequency / Rated Value":"50/60 Hz","Influence Of The Surrounding Temperature":"max. 95% to 55°C, max. 55% to 70°C, max. 35% to 75°C","at DC / acc. to IEC 60947-2 / rated value":"15 kA","at AC / acc. to UL 1077 and CSA C22.2 No.235":"5 kA","vibration resistance / acc. to IEC 60068-2-6":"±1mm at 5 to 25Hz; 50m/s² at 25 to 150Hz","Product Function / Neutral Conductor Switching":"No","with multi-phase operation / at AC / rated value":"440 V","operating voltage / at DC / rated value / maximum":"72 V","with single-phase operation / at AC / rated value":"440 V","Mechanical Service Life (Operating Cycles) / Typical":"10 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=221129&mlfb=5SY8401-8","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SY8401-8/alternatives.json"},"ai":{"faq":[{"question":"What is the breaking capacity of the 5SY8401-8?","answer":"70 kA at AC per IEC 60947-2, 15 kA at DC per the same standard, and 5 kA at AC per UL 1077 / CSA C22.2 No.235."},{"question":"What does the D-curve mean on this breaker?","answer":"The D tripping characteristic (10-20x In) is designed for loads with high inrush current such as small transformers, solenoid banks, and DC power supplies, avoiding nuisance tripping on startup."},{"question":"Where can I buy the 5SY8401-8 and get current pricing?","answer":"The 5SY8401-8 is 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 quote."},{"question":"What compliance documentation does Siemens provide for the 5SY8401-8?","answer":"The breaker carries IEC 60947-2 and UL 1077 / CSA C22.2 No.235 certifications. It is halogen-free and silicon-free. Standard compliance documentation (CE, UKCA, EAC) is provided with the product."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY8401-8","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/5SY8401-8 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}}