{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY7408-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY7408-8","canonicalUrl":"https://aoctrl.com/siemens/5SY7408-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SY7408-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY7408-8, 4-pole miniature circuit breaker, D tripping characteristic, 8 A rated current, 15 kA (EN 60898) / 30 kA (IEC 60947-2) breaking capacity, 400 V AC.","salesMarkdown":"## Siemens 5SY7408-8 — 4-pole D-curve MCB at 8 A Breaking capacity is 15 kA per EN 60898 and 30 kA per IEC 60947-2, so it clears faults up to that level without cascading upstream in a 400 V AC panel. ## D-curve application and breaking capacity The D characteristic is the key selection parameter here. Where a B-curve (3–5× In) protects resistive or lighting circuits and a C-curve (5–10× In) handles general-purpose inductive loads, the D-curve (10–20× In) is sized for loads with high magnetizing inrush — small motors, solenoid valves, power supplies, and transformers. At 8 A, this 4-pole version protects a three-phase motor drawing roughly 4 kW at 400 V, or a single-phase 230 V load up to about 1.8 kW per pole, provided the inrush does not exceed 160 A for the magnetic trip. Under UL 1077 and CSA C22.2 No. 235, the interrupting rating is 5 kA — relevant if the panel carries a UL mark. The 30 kA IEC 60947-2 rating gives selectivity headroom downstream of a larger upstream device. Sealable terminals allow the installer to lock the setting with a lead seal or tamper-evident tag, which is common in metering or rental-agreement panels. Touch protection is integrated on the terminals. Operating temperature range is -40 °C to 75 °C, with derating for humidity: 95% RH up to 55 °C, 55% RH up to 70 °C, and 35% RH up to 75 °C. Vibration resistance per IEC 60068-2-6 is ±1 mm at 5–25 Hz and 50 m/s² at 25–150 Hz — adequate for installation on machinery or in enclosures mounted on vibrating structures.","metaTitle":"Siemens 5SY7408-8 SENTRON MCB, 4P D 8A, 15kA EN 60898","metaDescription":"Siemens 5SY7408-8 SENTRON miniature circuit breaker, 4-pole, D-curve, 8 A rated current, 15 kA breaking capacity per EN 60898, 30 kA per IEC 60947-2. Active production, sourced to","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Miniature Circuit Breakers (MCB)"],"specifications":{"Depth":"76 mm","Width":"72 mm","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","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":"400 V","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","Combined Terminal Bottom":"Yes","Suitability For Operation":"Mechanical engineering / industry","Number Of Modular Width Units":"4","Tripping Characteristic Class":"D","acc. to EN 60898 / rated value":"15 kA","Position / Of Power Supply Cord":"Any","acc. to IEC 60947-2 / rated value":"30 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","operational current / at AC / rated value":"8 A","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 (Switching Cycles) / Typical":"10 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/00fc5c5fe789f17166fb5be870147edf.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=202057&mlfb=5SY7408-8","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SY7408-8/alternatives.json"},"ai":{"faq":[{"question":"What is the breaking capacity of 5SY7408-8?","answer":"15 kA per EN 60898 and 30 kA per IEC 60947-2 at 400 V AC. For DC circuits per IEC 60947-2 it is 15 kA; under UL 1077 and CSA C22.2 No. 235 it is 5 kA."},{"question":"What does the D-curve mean on this MCB?","answer":"The D tripping characteristic (10–20× In) is designed for loads with high inrush current — motors, transformers, welding equipment. At 8 A, the magnetic trip activates between 80 A and 160 A, so it will not nuisance-trip on start-up surge."},{"question":"Where can I buy 5SY7408-8?","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 commitment."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY7408-8","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/5SY7408-8 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}}