{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY8408-7","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY8408-7","canonicalUrl":"https://aoctrl.com/siemens/5SY8408-7","factsUrl":"https://aoctrl.com/api/mcp/products/5SY8408-7","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY8408-7, 4-pole miniature circuit breaker, C-curve 8 A, 40 kA breaking capacity per IEC 60947-2, 72 mm wide, current production.","salesMarkdown":"The Siemens SENTRON 5SY8408-7 is a 4-pole miniature circuit breaker (MCB) with a C-tripping characteristic rated at 8 A AC, designed for 50/60 Hz supply voltages. For UL 1077 / CSA C22.2 No.235 supplementary protection, it is rated 5 kA. This 40 kA IEC rating provides generous fault-current headroom for most commercial and industrial panelboards, supporting selective coordination with upstream devices without requiring a current-limiting upstream breaker in many installations. ## Thermal derating and environmental range The 8 A rating holds at 45 °C ambient. At 50 °C it derates to 7.75 A, and at 55 °C to 7.5 A. The operating temperature range spans -40 °C to 75 °C, with humidity limits of 95% up to 55 °C, 55% up to 70 °C, and 35% at 75 °C. Vibration resistance per IEC 60068-2-6 is ±1 mm at 5–25 Hz and 50 m/s² at 25–150 Hz. ## Material compliance Halogen-free and silicon-free construction. No neutral conductor switching function on this 4P unit — it switches all four poles as live conductors.","metaTitle":"Siemens 5SY8408-7 SENTRON MCB, 4P C-8A, 40kA IEC","metaDescription":"Siemens SENTRON 5SY8408-7 miniature circuit breaker, 4-pole, C-curve, 8 A, 40 kA IEC 60947-2, 72 mm wide, current production. Available 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","Width":"72 mm","title":"5SY8408-7","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","description":"Miniature circuit breaker 400 V D=70 mm 25 kA according to EN 60947-2, 4P, C8","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":"8 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":"8 A","at 50 °C / rated value":"7.75 A","at 55 °C / rated value":"7.5 A","Combined Terminal Bottom":"Yes","Suitability For Operation":"Mechanical engineering / industry","Number Of Modular Width Units":"4","Tripping Characteristic Class":"C","Position / Of Power Supply Cord":"Any","acc. to IEC 60947-2 / rated value":"40 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,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/0dbe189cdc1f04656ea850e69063050d.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=25848&mlfb=5SY8408-7"},"ai":{"faq":[{"question":"Where can I buy 5SY8408-7 and what is the lead time?","answer":"This part 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 lead-time estimate."},{"question":"What is the breaking capacity of 5SY8408-7?","answer":"40 kA per IEC 60947-2 at AC, 15 kA at DC under the same standard, and 5 kA per UL 1077 / CSA C22.2 No.235 for supplementary protection."},{"question":"What compliance documentation does Siemens provide for 5SY8408-7?","answer":"The part is halogen-free and silicon-free. It carries IEC 60947-2 and UL 1077 / CSA C22.2 No.235 ratings, indicating compliance with those standards. RoHS and REACH declarations are standard for current-production Siemens SENTRON MCBs."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY8408-7","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/5SY8408-7 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}}