{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY8304-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY8304-8","canonicalUrl":"https://aoctrl.com/siemens/5SY8304-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SY8304-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON, miniature circuit breaker, 5SY8304-8, 3-pole, 4 A, D tripping characteristic, 50 kA at 400 V AC per IEC 60947-2.","salesMarkdown":"## What the ratings mean for your panel The Siemens 5SY8304-8 is a SENTRON miniature circuit breaker with a D tripping characteristic, rated 4 A and built to protect circuits with high inrush currents — think motor starters, small transformers, or solenoid banks that pull several times their running current on startup. The D curve means it tolerates short-duration surges up to 10–20 times the rated current before tripping, which keeps nuisance trips off the floor on a line full of inductive loads. Its 50 kA breaking capacity at 400 V AC (per IEC 60947-2) tells you it can safely clear a fault up to that level without welding its contacts or blowing apart — important when the available fault current at the panel is high. That rating is the one that governs selectivity with upstream gear; you match the kA rating to the supply transformer's short-circuit capability. Temperature derating is baked in: at 45 °C it holds the full 4 A, at 50 °C it drops to 3.9 A, and at 55 °C to 3.8 A. If your panel runs hot — near a drive cabinet or in a non-climate-controlled enclosure — factor that derating into the load calculation so you don't get unexpected trips on a warm afternoon. ## Mounting and integration Snaps onto standard DIN rail via the quick-assembly system, 3 modular-width units wide (54 mm). Mounting position is any orientation, which helps in tight enclosures. Depth is 76 mm with an installation depth of 70 mm — factor that into door clearance if you're using a cover or handle extension. IP20 with connected conductors — fine inside a closed panel, not for washdown zones. Pollution degree 3 and overvoltage category III mean it's built for industrial environments where conductive dust or condensation may be present.","metaTitle":"Siemens 5SY8304-8 SENTRON MCB, 4A D Curve 3P 50kA","metaDescription":"Siemens 5SY8304-8 SENTRON miniature circuit breaker, 4 A rated, D tripping characteristic, 3-pole, 50 kA breaking capacity per IEC 60947-2. Sourced to order; confirm current pricin","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["3-Pole MCB (DIN Rail)"],"specifications":{"Depth":"76 mm","Width":"54 mm","title":"5SY8304-8","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, 3P, D4","Halogen-Free":"Yes","Silicon-Free":"Yes","Design Of Pole":"3P","Number Of Poles":"3","lifecycle_stage":"current","Fastening Method":"Quick assembly system","Mounting Position":"any","at AC rated value":"4 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":"4 A","at 50 °C rated value":"3.9 A","at 55 °C rated value":"3.8 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":"3","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/65cbb4c871edbe0056695abbdc62eb82.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=298478&mlfb=5SY8304-8"},"ai":{"faq":[{"question":"What does the D tripping characteristic mean for my application?","answer":"The D curve is designed for circuits with high inrush currents — typically motor feeders, small transformers, or welding equipment. It allows momentary surges of 10–20 times the rated current without tripping, so it won't nuisance-trip when a motor starts or a transformer energizes."},{"question":"What is the breaking capacity of the 5SY8304-8?","answer":"50 kA at 400 V AC per IEC 60947-2, and 15 kA at 72 V DC. That AC rating is high enough for most industrial panelboards fed by a typical distribution transformer."},{"question":"Where can I buy the 5SY8304-8?","answer":"Sourced and quoted to order against an RFQ through independent industrial-automation distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm commitment on your line item."},{"question":"Will the 5SY8304-8 drop into a panel designed for a 5SY4310-7CV?","answer":"Both are 3-pole SENTRON MCBs on the same DIN-rail footprint, so the mechanical fit is the same — 3 modular-width units, same depth. The difference is rating: the 5SY8304-8 is a 4 A D-curve, while the 5SY4310-7CV is a different rating and curve. Verify the load and tripping coordination before swapping; the physical swap is straightforward."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY8304-8","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/5SY8304-8 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}}