{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY4408-7","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY4408-7","canonicalUrl":"https://aoctrl.com/siemens/5SY4408-7","factsUrl":"https://aoctrl.com/api/mcp/products/5SY4408-7","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY4408-7, 4-pole miniature circuit breaker, 8 A, C-curve, 400 V AC, 10 kA / 20 kA, 72 mm wide, halogen-free.","salesMarkdown":"## What this MCB does, and why it fits your BOM line The 5SY4408-7 is a current-production 4-pole miniature circuit breaker from the Siemens SENTRON 5SY4 series, rated 8 A at 400 V AC with a C-characteristic trip curve — the standard choice for general-purpose industrial loads such as small motors, control transformers, and lighting circuits where a moderate inrush current ride-through is needed. Ambient range spans –40 to +70 °C operating, with storage down to –40 °C and a derated humidity profile above 55 °C; the breaker holds calibration across that band, provided the surrounding air stays within those limits. Production status is active — this is not an end-of-life part. Quote it against the BOM line as a current catalogue item; no last-time-buy clock to watch. The closest peer in the same SENTRON 5SY4 family is the 5SY4406-7, identical in every physical dimension (72 mm wide, 76 mm deep, 4 width units) and terminal range, but rated 6 A instead of 8 A. A panel wired for the 6 A version needs no mechanical rework to accept the 5SY4408-7 — the current rating is the only procurement difference. Ensure the load cable and upstream protection are sized for 8 A before swapping. ## Mounting and installation notes Installation depth is 70 mm (with a total depth of 76 mm including the actuator), so it clears most shallow distribution boxes. Combined top and bottom terminals allow in/out feed from either direction; the sealable cover option is available if tamper-proofing is required. Rated for overvoltage category III, meaning it's intended for fixed installations inside the panel — not for outdoor use without additional enclosure protection.","metaTitle":"Siemens 5SY4408-7 SENTRON MCB, 8A 4P C-curve","metaDescription":"Siemens 5SY4408-7 SENTRON 4-pole miniature circuit breaker, 8 A, C-curve, 400 V AC, 10/20 kA breaking capacity. Current production. 72 mm wide, halogen-free. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["4-Pole MCB (DIN Rail)"],"specifications":{"Depth":"76 mm","Solid":"0.75 ... 35 mm²","Width":"72 mm","title":"5SY4408-7","Height":"90 mm","Sealable":"Yes","Stranded":"0.75 ... 35 mm²","Rated Value":"50/60 Hz","description":"Miniature circuit breaker 400 V 10kA, 4-pole, C, 8A, D=70 mm","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":"-40 ... +70 °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","Energy limiting class":"3","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":"5SY4","Suitability for operation":"Mechanical engineering / industry","Current / at AC / rated value":"8 A","Tripping characteristic class":"C","at DC / rated value / maximum":"72 V","acc. to EN 60898 / rated value":"10 kA","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 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":"$338.66","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/a9688bea0c869212a9e6855f4bd60cd6.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=328362&mlfb=5SY4408-7"},"ai":{"faq":[{"question":"Will the 5SY4408-7 fit a panel built for the 5SY4406-7?","answer":"Yes, the mechanical footprint is identical — same width, depth, terminal range, and mounting. The only change is the rated current (8 A vs 6 A). Verify that the load and upstream protection are rated for 8 A before substituting."},{"question":"What wire sizes does the terminal accept?","answer":"Solid and stranded conductors from 0.75 mm² up to 35 mm². The terminal is sealed for IP20 with conductors connected."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY4408-7","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/5SY4408-7 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}}