{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY8203-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY8203-8","canonicalUrl":"https://aoctrl.com/siemens/5SY8203-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SY8203-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY8203-8 miniature circuit breaker, D characteristic, 3 A, 2-pole, 50 kA at 440 V AC, 15 kA at 72 V DC.","salesMarkdown":"The Siemens 5SY8203-8 is a SENTRON miniature circuit breaker (MCB) with a D tripping characteristic, rated 3 A at 45 °C ambient, 2-pole design, and a 50 kA breaking capacity per IEC 60947-2 at 440 V AC. At 50 °C the continuous rating derates to 2.91 A; at 55 °C it drops to 2.81 A. The part is rated for ambient humidity up to 95% at 55 °C, tapering to 35% at 75 °C. This matters when the breaker lives inside a non-ventilated enclosure near hot machinery — the real-world ampacity may be lower than the nameplate 3 A, so size the upstream protection accordingly. The DC side is rated 15 kA at 72 V maximum, so it also works in DC control circuits or battery-backed bus bars within that voltage ceiling. The combined terminal at top and bottom accepts the same conductor range — no special feed-through lug needed. Halogen-free and silicon-free construction, sealable for lockout/tagout. Neutral conductor is not switched — this is a 2-pole breaker switching both phases (line and load side) but leaving the neutral bar continuous. The supply cord can enter from any position.","metaTitle":"Siemens 5SY8203-8 SENTRON MCB, D Curve, 3 A, 2-Pole, 50 kA","metaDescription":"Siemens 5SY8203-8 SENTRON miniature circuit breaker, D tripping characteristic, 3 A rated, 2-pole, 50 kA breaking capacity at 440 V AC. Active production, sourced to order. Request","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["2-Pole MCB (DIN Rail)"],"specifications":{"Depth":"76 mm","Width":"36 mm","title":"5SY8203-8","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, 2P, D3","Halogen-Free":"Yes","Silicon-Free":"Yes","Design Of Pole":"2P","Number Of Poles":"2","lifecycle_stage":"current","Fastening Method":"Quick assembly system","Mounting Position":"any","at AC rated value":"3 A","Installation Depth":"70 mm","Product Brand Name":"SENTRON","Degree Of Pollution":"3","Product Designation":"Miniature circuit breaker","protection class IP":"IP20, with connected conductors","Overvoltage Category":"III","Combined Terminal Top":"Yes","at 45 °C rated value":"3 A","at 50 °C rated value":"2.91 A","at 55 °C rated value":"2.81 A","according to EN 61346-2":"F","Combined Terminal Bottom":"Yes","according to IEC 81346-2":"F","Suitability For Operation":"Mechanical engineering / industry","Neutral Conductor Switching":"No","Number Of Modular Width Units":"2","Position Of Power Supply Cord":"Any","Tripping Characteristic Class":"D","according to IEC 60947-2 rated value":"50 kA","Influence Of The Surrounding Temperature":"max. 95% to 55°C, max. 55% to 70°C, max. 35% to 75°C","Type Of Voltage Of The Operating Voltage":"AC","at DC according to IEC 60947-2 rated value":"15 kA","Value Range Of The Supply Voltage Frequency":"50/60 Hz","operating voltage at DC rated value maximum":"72 V","with multi-phase operation at AC rated value":"440 V","with single-phase operation at AC rated value":"440 V","at AC according to UL 1077 and CSA C22.2 No.235":"5 kA","vibration resistance according to IEC 60068-2-6":"±1mm at 5 to 25Hz; 50m/s² at 25 to 150Hz","Mechanical Service Life (Switching Cycles) Typical":"10 000","Product Extension Installable Supplementary Devices":"Yes","supply voltage with single-phase operation at AC rated value":"230 V","power loss [W] for rated value of the current at AC in hot operating state per pole":"1.2 W"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/817684e059228083ce20595b4ec6b412.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=453680&mlfb=5SY8203-8"},"ai":{"faq":[{"question":"What is the breaking capacity of 5SY8203-8 at 440 V AC?","answer":"50 kA per IEC 60947-2 at 440 V AC, single-phase or multi-phase operation. At DC the rating is 15 kA at 72 V maximum."},{"question":"What does the D tripping characteristic mean for this 3 A breaker?","answer":"The D curve allows magnetic trip at 10 to 20 times rated current (30–60 A instantaneous), so it handles motor inrush, transformer magnetizing current, or capacitive loads without tripping on start-up."},{"question":"Where can I buy 5SY8203-8 and get current pricing?","answer":"The part is sourced and quoted to order against an RFQ through independent distribution; availability and current pricing are confirmed at quote time."},{"question":"Will 5SY8203-8 drop into a panel specified around 5SY7206-7CC?","answer":"Both are 2-module-wide (36 mm) SENTRON MCBs on the same DIN-rail footprint, so the panel cutout and busbar spacing are identical. The difference is the tripping curve and rating — 5SY8203-8 is D curve 3 A, while 5SY7206-7CC is a different characteristic and ampacity. Verify the circuit's coordination study before swapping."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY8203-8","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/5SY8203-8 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}}