{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY6303-8CC","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY6303-8CC","canonicalUrl":"https://aoctrl.com/siemens/5SY6303-8CC","factsUrl":"https://aoctrl.com/api/mcp/products/5SY6303-8CC","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY6 series, miniature circuit breaker (MCB), order code 5SY6303-8CC, 3 A rated current, D characteristic, 3-pole, 6 kA breaking capacity per EN 60898.","salesMarkdown":"## What it is and what the ratings mean The Siemens 5SY6303-8CC is a SENTRON miniature circuit breaker (MCB) with a D tripping characteristic, rated 3 A at AC, 50/60 Hz. The D-curve means it tolerates high inrush currents — typically 10 to 20 times the rated current for short durations — making it the right choice for motor, transformer, or lighting ballast circuits where the start-up surge would nuisance-trip a B or C curve. The 6 kA breaking capacity per EN 60898 (5 kA per UL 1077 / CSA C22.2 No.235) tells you it can safely interrupt a fault current up to that level without welding contacts or cascading damage upstream. Overvoltage category III and pollution degree 3 mean it's rated for fixed-installation distribution panels, not just clean indoor environments. ## Derating and thermal environment The 3 A rating holds at 40 °C ambient. Above that, the breaker derates linearly: 2.82 A at 40 °C, 2.73 A at 45 °C, 2.63 A at 50 °C, and 2.53 A at 55 °C. If your panel runs hot — say inside a non-ventilated enclosure near a drive — size the load or the breaker accordingly. The operating range spans -40 °C to 75 °C, with humidity limits that step down above 55 °C (95% RH up to 55 °C, 55% up to 70 °C, 35% up to 75 °C). That covers most industrial environments short of direct washdown. ## Panel integration and mounting Snaps onto DIN rail via the quick assembly system — no tools needed. Occupies 3 modular width units (54 mm wide). Mounting position is any orientation, which simplifies layout in crowded enclosures. Installation depth is 70 mm; overall depth is 76 mm. Combined terminals top and bottom accept the same conductor range, so you don't need separate feed-through lugs. IP20 with connected conductors — fine for enclosed distribution boards, not for exposed outdoor use without an outer cabinet. Sealable, halogen-free, silicon-free — relevant for food, pharma, or clean-room panels where outgassing or contamination is a concern.","metaTitle":"Siemens 5SY6303-8CC SENTRON MCB, 3A D-Curve, 3-Pole, 6kA","metaDescription":"Siemens 5SY6303-8CC SENTRON miniature circuit breaker, 3 A rated, D tripping characteristic, 3-pole, 6 kA breaking capacity per EN 60898. Active production, available to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["3-Pole MCB (DIN Rail)"],"specifications":{"Depth":"76 mm","Width":"54 mm","title":"5SY6303-8CC","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","description":"Miniature circuit breaker 400 V 6kA, 3-pole, D, 3 A","Halogen-Free":"Yes","Silicon-Free":"Yes","Number Of Poles":"3","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":"3 A","protection class IP":"IP20, with connected conductors","Overvoltage Category":"III","Combined Terminal Top":"Yes","Number Of Poles / Note":"3P","acc. to DIN EN 61346-2":"F","at 40 °C / rated value":"2.82 A","at 45 °C / rated value":"2.73 A","at 50 °C / rated value":"2.63 A","at 55 °C / rated value":"2.53 A","Combined Terminal Bottom":"Yes","Suitability For Operation":"Mechanical engineering / industry","Number Of Modular Width Units":"3","Tripping Characteristic Class":"D","acc. to EN 60898 / rated value":"6 kA","Position / Of Power Supply Cord":"Any","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 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,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/c2f9b08c60c2dd4f7ffe46487b1b11d3.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=433379&mlfb=5SY6303-8CC"},"ai":{"faq":[{"question":"Where can I buy 5SY6303-8CC and get a price?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution channels. Submit an RFQ for current availability and pricing — confirmed at quote time."},{"question":"What is the D-curve on this MCB for?","answer":"The D tripping characteristic (10–20× In) is designed for loads with high inrush current, such as small motors, transformers, or discharge lighting, where a B or C curve would nuisance-trip on startup."},{"question":"What compliance documentation does Siemens provide for 5SY6303-8CC?","answer":"The breaker is rated per EN 60898 (6 kA) and UL 1077 / CSA C22.2 No.235 (5 kA). It carries overvoltage category III and pollution degree 3 ratings, suitable for fixed-installation distribution panels."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY6303-8CC","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/5SY6303-8CC 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}}