{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY8240-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY8240-8","canonicalUrl":"https://aoctrl.com/siemens/5SY8240-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SY8240-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY8240-8, 2-pole miniature circuit breaker, D tripping characteristic, 25 kA at 400 V AC per IEC 60947-2, IP20, 2 MW wide.","salesMarkdown":"## What the ratings mean for fit The Siemens 5SY8240-8 is a 2-pole SENTRON miniature circuit breaker with a D tripping characteristic, rated to interrupt 25 kA at 400 V AC per IEC 60947-2. The D curve means it tolerates the high inrush currents typical of motor loads, transformers, and welding equipment — the magnetic trip threshold is 10 to 20 times rated current, so it won't nuisance-trip on startup. The 25 kA breaking capacity at 400 V AC gives you headroom for high-fault installations; at 60 V DC it still clears 15 kA, and under UL 1077 it's listed at 5 kA for North American supplementary protection applications. That triple-standard coverage (IEC 60947-2, EN 60947-2, UL 1077) means the same part works in European panel builds and US control panels without a substitution. ## Deployment context and panel integration Snaps onto DIN rail via the quick-assembly system — 2 modular width units (36 mm wide) leave room for adjacent devices in a crowded enclosure. The 76 mm depth and 70 mm installation depth fit standard distribution boards; mount in any position. IP20 with connected conductors means it's protected against finger contact once wired, suitable for enclosed industrial panels. The combined top and bottom terminals accept supply from either direction, which simplifies busbar routing in a multi-breaker row. ## Environmental and mechanical robustness Rated for ambient temperatures from -40 °C to 75 °C, with humidity tolerance up to 95% at 55 °C — suitable for unheated enclosures in cold storage or outdoor cabinets. Vibration resistance per IEC 60068-2-6 covers ±1 mm at 5 to 25 Hz and 50 m/s² at 25 to 150 Hz, so it holds up on machinery with moderate vibration. Halogen-free and silicon-free construction matters for clean-room or semiconductor-adjacent installations where outgassing contaminates processes. Mechanical service life is 10,000 operating cycles typical.","metaTitle":"Siemens 5SY8240-8 SENTRON MCB, 2-pole D-curve, 25 kA IEC","metaDescription":"Siemens 5SY8240-8 SENTRON miniature circuit breaker, 2-pole, D tripping characteristic, 25 kA at 400 V AC per IEC 60947-2. Active production, sourced to order. Request a quote.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["2-Pole MCB (DIN Rail)"],"specifications":{"Depth":"76 mm","Width":"36 mm","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","Standard":"IEC / EN 60947-2 / UL1077","Halogen-Free":"Yes","Silicon-Free":"Yes","Design Of Pole":"2P","Number Of Poles":"2","lifecycle_stage":"current","Fastening Method":"Quick assembly system","Mounting Position":"any","at AC rated value":"400 V","at DC rated value":"60 V","Installation Depth":"70 mm","Product Brand Name":"SENTRON","Degree Of Pollution":"3","Product Designation":"Miniature circuit breaker","protection class IP":"IP20, with connected conductors","Overvoltage Category":"III","Combined Terminal Top":"Yes","Combined Terminal Bottom":"Yes","Suitability For Operation":"Mechanical engineering / industry","Neutral Conductor Switching":"No","Number Of Modular Width Units":"2","Position Of Power Supply Cord":"Any","Tripping Characteristic Class":"D","according to IEC 60947-2 rated value":"25 kA","Influence Of The Surrounding Temperature":"max. 95% to 55°C, max. 55% to 70°C, max. 35% to 75°C","Type Of Voltage Of The Operating Voltage":"AC","at DC according to IEC 60947-2 rated value":"15 kA","Value Range Of The Supply Voltage Frequency":"50/60 Hz","operating voltage at DC rated value maximum":"72 V","with multi-phase operation at AC rated value":"440 V","with single-phase operation at AC rated value":"440 V","at AC according to UL 1077 and CSA C22.2 No.235":"5 kA","vibration resistance according to IEC 60068-2-6":"±1mm at 5 to 25Hz; 50m/s² at 25 to 150Hz","Mechanical Service Life (Operating Cycles) Typical":"10 000","Product Extension Installable Supplementary Devices":"Yes","supply voltage with single-phase operation at AC rated value":"230 V","power loss [W] for rated value of the current at AC in hot operating state per pole":"3 W"}},"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=22708&mlfb=5SY8240-8","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SY8240-8/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy the 5SY8240-8 and get a price?","answer":"We source and quote the 5SY8240-8 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."},{"question":"Will the 5SY8240-8 drop into a panel specified for the 5SY4140-7?","answer":"Yes, the 5SY8240-8 shares the same DIN-rail footprint and 2-modular-width (36 mm) form factor, so it mounts without rewiring. However, the 5SY8240-8 uses a D tripping curve (10-20x In) versus the B curve (3-5x In) of the 5SY4140-7 — verify coordination with downstream loads before swapping."},{"question":"What compliance documentation does Siemens provide for the 5SY8240-8?","answer":"The 5SY8240-8 is certified to IEC / EN 60947-2 and UL 1077, covering European and North American supplementary protection. It is halogen-free and silicon-free. Standard Siemens documentation includes the declaration of conformity, CE marking, and UL recognition — request specific certificates with your RFQ."},{"question":"What is the depth of the 5SY8240-8?","answer":"The 5SY8240-8 has a depth of 76 mm, with an installation depth of 70 mm. Width is 36 mm (2 modular units), height is 90 mm."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY8240-8","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/5SY8240-8 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}}