{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY6408-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY6408-8","canonicalUrl":"https://aoctrl.com/siemens/5SY6408-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SY6408-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY6 series, 4-pole miniature circuit breaker, D tripping characteristic, 8 A rated current, 400 V AC, breaking capacity 6 kA per EN 60898 / 15 kA per IEC 60947-2, order code 5SY6408-8.","salesMarkdown":"## What this 4-pole D-curve MCB is for The Siemens 5SY6408-8 is a 4-pole miniature circuit breaker from the SENTRON 5SY6 series, rated 8 A with a D tripping characteristic at 400 V AC. It breaks 6 kA under EN 60898 for standard household/commercial duty and 15 kA under IEC 60947-2 for industrial panel applications, so you can use it downstream of a transformer or in a sub-distribution board without worrying about fault current coordination. This is a current-production part — lifecycle stage marked current. Width is 72 mm (4 width units on a DIN rail), depth 76 mm, height 90 mm, with an installation depth of 70 mm. IP20 with connected conductors; touch protection is built in. Sealable and halogen-free, silicon-free construction — relevant for food processing or clean-room panels where outgassing matters. ## Breaking capacity and approvals Three breaking-capacity ratings cover the main standards: 6 kA per EN 60898 (the residential/commercial standard), 15 kA per IEC 60947-2 (industrial), and 5 kA per UL 1077 / CSA C22.2 No.235 (North American supplementary protector). Overvoltage category III, rated impulse withstand for fixed installation. The DC rating maxes out at 72 V — fine for control circuits but not for high-voltage DC bus work.","metaTitle":"Siemens 5SY6408-8 SENTRON MCB, 4P D 8 A, 6/15 kA","metaDescription":"Siemens 5SY6408-8 SENTRON 4-pole miniature circuit breaker, D-curve, 8 A rated, 400 V AC. Breaking capacity 6 kA (EN 60898) / 15 kA (IEC 60947-2). Active production, sourced to ord","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"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 ... +55 °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","Number of width units":"4","Number of poles / Note":"4P","acc. to DIN EN 61346-2":"F","acc. to DIN EN 81346-2":"F","Combined Terminal Bottom":"Yes","circuit-breaker / Design":"5SY6","Suitability for operation":"Mechanical engineering / industry","Current / at AC / rated value":"8 A","Tripping characteristic class":"D","at DC / rated value / maximum":"72 V","acc. to EN 60898 / rated value":"6 kA","Position / of power supply cord":"Any","acc. to IEC 60947-2 / rated value":"15 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 DC / acc. to IEC 60947-2 / rated value":"15 kA","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":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=485884&mlfb=5SY6408-8","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SY6408-8/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 5SY6408-8 and how do I get a price?","answer":"This part is sourced to order through independent distribution. Submit an RFQ for current availability and pricing — confirmed at quote time."},{"question":"Will 5SY6408-8 drop into a panel specified around 5SY4140-7 without rewiring?","answer":"No. The 5SY6408-8 is a 4-pole D-curve 8 A breaker; the 5SY4140-7 is a different pole/curve/current variant. They share the SENTRON 5SY family footprint and DIN-rail mount, but the ratings differ — verify the BOM line before substituting."},{"question":"What compliance documentation does Siemens provide for 5SY6408-8?","answer":"The part carries approvals per EN 60898, IEC 60947-2, and UL 1077 / CSA C22.2 No.235. RoHS and REACH declarations are standard with Siemens SENTRON products. Request specific certificates at quote time."},{"question":"What is 5SY6408-8's depth?","answer":"76 mm overall depth, with an installation depth of 70 mm."},{"question":"What conductor sizes does the 5SY6408-8 terminal accept?","answer":"Solid and stranded conductors from 0.75 to 35 mm²."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY6408-8","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/5SY6408-8 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}}