{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY8503-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY8503-8","canonicalUrl":"https://aoctrl.com/siemens/5SY8503-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SY8503-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON miniature circuit breaker, 5SY8503-8, 2-pole 1P+N, D tripping characteristic, 50 kA breaking capacity at 230 V AC, 36 mm wide, IP20.","salesMarkdown":"It's rated for 230 V AC at 50/60 Hz and carries a 50 kA breaking capacity under IEC 60947-2 — that's the rating that governs fault clearing in industrial panels where high prospective short-circuit currents are expected. The 76 mm depth includes the quick-assembly system and combined top/bottom terminals. The 50 kA at 230 V AC (IEC 60947-2) is the headline number for selectivity studies. For DC circuits, it's rated 15 kA per IEC 60947-2. Under UL 1077 and CSA C22.2 No. 235, the breaking capacity is 5 kA — that's the figure a panel builder needs when the spec calls for UL-listed branch protection rather than IEC. Temperature derating is built in: at 45 °C the rated current is 3 A, dropping to 2.91 A at 50 °C and 2.81 A at 55 °C. ## Installation notes Mounts in any position on DIN rail. The neutral conductor is switched (1P+N), so it's not a straight 2-pole breaker — the neutral pole opens with the line pole, which matters for isolation requirements. The combined terminal at top and bottom accepts the same wire size range; the sealable option (yes) allows locking the cover after commissioning to prevent tampering. Halogen-free and silicon-free construction, so it's safe for use in clean-room or food-processing zones where outgassing is a concern.","metaTitle":"Siemens 5SY8503-8 SENTRON MCB, 2-Pole D-Curve, 50 kA","metaDescription":"Siemens 5SY8503-8 SENTRON miniature circuit breaker, 2-pole 1P+N, D tripping characteristic, 50 kA IEC breaking capacity, 230 V AC, -40 to 75 °C. Active production, available to or","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["1-Pole MCB (DIN Rail)"],"specifications":{"Depth":"76 mm","Width":"36 mm","title":"5SY8503-8","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","description":"Miniature circuit breaker 230 V D=70 mm 25 kA according to EN 60947-2, 1P+N, D3","Halogen-Free":"Yes","Silicon-Free":"Yes","Number Of Poles":"2","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":"230 V","protection class IP":"IP20, with connected conductors","Overvoltage Category":"III","Combined Terminal Top":"Yes","Number Of Poles / Note":"1P+N","acc. to DIN EN 61346-2":"F","at 45 °C / rated value":"3 A","at 50 °C / rated value":"2.91 A","at 55 °C / rated value":"2.81 A","Combined Terminal Bottom":"Yes","Suitability For Operation":"Mechanical engineering / industry","Number Of Modular Width Units":"2","Tripping Characteristic Class":"D","Position / Of Power Supply Cord":"Any","acc. to IEC 60947-2 / rated value":"50 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":"Yes","operating voltage / at DC / rated value / maximum":"72 V","with single-phase operation / at AC / rated value":"250 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/3282a6c9236b99040601f12099c1065a.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=183044&mlfb=5SY8503-8"},"ai":{"faq":[{"question":"What is the breaking capacity of 5SY8503-8?","answer":"Under IEC 60947-2, the breaking capacity is 50 kA at 230 V AC and 15 kA DC. Under UL 1077 and CSA C22.2 No. 235, it's 5 kA."},{"question":"Where can I buy 5SY8503-8 and how is it quoted?","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 quote."},{"question":"What is the tripping characteristic of 5SY8503-8?","answer":"It has a D tripping characteristic (10–20× In), designed for loads with high inrush current such as motors and transformers."},{"question":"Will 5SY8503-8 drop into a panel specified around 5SY4140-7?","answer":"Both are 2-module-wide (36 mm) SENTRON MCBs on DIN rail, so the mechanical fit is the same. But 5SY8503-8 is a D-curve 1P+N breaker with 50 kA IEC breaking capacity, while 5SY4140-7 is a different rating and curve — verify the electrical specs (current, curve, poles) before substituting."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY8503-8","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/5SY8503-8 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}}