{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY4440-8CV","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY4440-8CV","canonicalUrl":"https://aoctrl.com/siemens/5SY4440-8CV","factsUrl":"https://aoctrl.com/api/mcp/products/5SY4440-8CV","rawCanonicalId":null},"summary":{"shortDescription":"Siemens 5SY4440-8CV, MCB Icu=15kA 400V 4P D40.","salesMarkdown":"The Siemens 5SY4440-8CV is a 4-pole miniature circuit breaker (MCB) with a D40 characteristic, rated for a 15 kA breaking capacity (Icu) at 400 V. For a mill environment, that 15 kA Icu at 400 V gives you the fault-clearing headroom to maintain selectivity downstream without cascading upstream breakers on a bolted fault. The 4-pole configuration (3 phases + neutral) is standard for three-phase four-wire systems where the neutral needs overcurrent protection. The D40 thermal-magnetic curve: thermal trip at 40 A continuous, magnetic trip between 10x and 20x In (400–800 A), so it won't nuisance-trip on motor starting but clears fast on a hard short. ## Panel integration Snap-on DIN rail mounting per EN 60715. The 4-pole width is 72 mm (4 x 18 mm modules). Wire termination accepts up to 25 mm² for the line and load terminals. Busbar comb can bridge the incoming side across all four poles for a common feed.","metaTitle":"Siemens 5SY4440-8CV MCB, 15kA 400V 4P D40","metaDescription":"Siemens 5SY4440-8CV miniature circuit breaker, 15kA breaking capacity at 400V, 4-pole D-curve 40A. Currently in production. Quoted to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Miniature Circuit Breakers (MCB)"],"specifications":{"title":"5SY4440-8CV","description":"MCB Icu=15KA 400V 4P D40","lifecycle_stage":"current"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/1b061888df494b4b75e097ae728baefa.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=1531637&mlfb=5SY4440-8CV"},"ai":{"faq":[{"question":"Where can I buy the 5SY4440-8CV?","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 price and lead-time estimate."},{"question":"What does the D40 curve mean on this MCB?","answer":"D-curve means the magnetic trip operates between 10x and 20x rated current (400–800 A for a 40 A breaker). It's intended for loads with high inrush — motors, transformers, discharge lighting — where a B or C curve would trip on startup."},{"question":"What is the breaking capacity of the 5SY4440-8CV?","answer":"The Icu (ultimate breaking capacity) is 15 kA at 400 V AC. That's the maximum fault current the breaker can safely interrupt without damage."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY4440-8CV","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/5SY4440-8CV when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}