{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY6405-7","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY6405-7","canonicalUrl":"https://aoctrl.com/siemens/5SY6405-7","factsUrl":"https://aoctrl.com/api/mcp/products/5SY6405-7","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY6405-7, 4-pole miniature circuit breaker, C-curve, 0.5 A at 35°C, 400 V AC, 6 kA / 30 kA interrupting capacity.","salesMarkdown":"## What this MCB does on a panel The Siemens 5SY6405-7 is a 4-pole miniature circuit breaker from the SENTRON family, rated 0.5 A at 35 °C with a C tripping curve — meaning it holds through mild inrush (5–10x rated) and trips fast on hard faults. The 4-pole (4P) configuration gives you full isolation on all phases plus neutral, which matters when you're working on a three-phase line and need to kill everything upstream. The 72 mm width (4 modular width units) takes up standard panel space, and the 76 mm depth plus 70 mm installation depth means it clears most shallow enclosures. IP20 with connected conductors keeps it safe for enclosed panels; pollution degree 3 handles conductive dust in industrial air. ## Breaking capacity — the real number for selectivity Energy limitation class 3 means it lets through less let-through energy than a standard Class 3 device, which helps downstream components survive a fault. ## Thermal derating — what the 0.5 A actually means at panel temp The 0.5 A rating is at 35 °C ambient. If your panel runs hotter — and most industrial panels do — you need to derate: 0.48 A at 40 °C, 0.46 A at 45 °C, 0.45 A at 50 °C, 0.44 A at 55 °C. That's a roughly 4% drop per 5 °C rise. A 0.5 A breaker in a 50 °C cabinet is effectively a 0.45 A breaker. If your load draws 0.48 A continuous, you need to move up one frame size or ventilate the panel.","metaTitle":"Siemens 5SY6405-7 SENTRON MCB, 4-Pole C-Curve 0.5A 400V AC","metaDescription":"Siemens 5SY6405-7 SENTRON miniature circuit breaker, 4-pole, C-curve, 0.5 A rated at 35°C, 400 V AC, 6 kA (EN 60898) / 30 kA (IEC 60947-2). In current production. 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","Width":"72 mm","title":"5SY6405-7","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","description":"Miniature circuit breaker 400 V 6kA, 4-pole, C, 0.5A, D=70 mm","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","Energy Limitation Class":"3","at 35 °C / rated value":"0.5 A","at 40 °C / rated value":"0.48 A","at 45 °C / rated value":"0.46 A","at 50 °C / rated value":"0.45 A","at 55 °C / rated value":"0.44 A","Combined Terminal Bottom":"Yes","Suitability For Operation":"Mechanical engineering / industry","Number Of Modular Width Units":"4","Tripping Characteristic Class":"C","acc. to EN 60898 / rated value":"6 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","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/566f93ed0c815087521256f8a03e6255.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=248630&mlfb=5SY6405-7"},"ai":{"faq":[{"question":"What are the key ratings for the 5SY6405-7?","answer":"4-pole, C-curve, 0.5 A at 35 °C, 400 V AC, 50/60 Hz. Interrupting capacity: 6 kA per EN 60898, 30 kA per IEC 60947-2. Energy limitation class 3. Operating temperature range -40 °C to +75 °C."},{"question":"Where can I buy the 5SY6405-7 and get a price?","answer":"We source and quote this part to order against an RFQ. Current availability and pricing are confirmed at quote time through our independent distribution channel."},{"question":"Will the 5SY6405-7 drop into a panel built for the 5SY4310-7CV?","answer":"Both are 4-pole SENTRON MCBs on the same DIN-rail footprint (72 mm width, 4 MW units). The 5SY6405-7 is a 0.5 A C-curve; the 5SY4310-7CV is a higher-current variant. Panel cutouts and busbar connections are identical — no rewiring needed, just swap the breaker and verify the load current matches the new rating."},{"question":"What compliance documentation does Siemens provide for the 5SY6405-7?","answer":"As a SENTRON MCB, it carries CE marking per the Low Voltage Directive and is designed to EN 60898 and IEC 60947-2. The part is halogen-free and silicon-free. Specific RoHS/REACH declarations are available from Siemens upon request; we can include them with your order."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY6405-7","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/5SY6405-7 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}}