{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY4125-5","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY4125-5","canonicalUrl":"https://aoctrl.com/siemens/5SY4125-5","factsUrl":"https://aoctrl.com/api/mcp/products/5SY4125-5","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY4125-5, 1-pole miniature circuit breaker, 25 A, tripping characteristic A, 10 kA per EN 60898 / 20 kA per IEC 60947-2, 1 MW, IP20, 18 mm wide.","salesMarkdown":"## What you're looking at That characteristic A means it trips between 2 and 3 times rated current — tight, fast — so it's the go-to for protecting semiconductor circuits, control transformers, and sensitive electronic loads where a standard B or C curve would let through too much energy before opening. Breaking capacity is 10 kA per EN 60898 and 20 kA per IEC 60947-2 — the higher figure under the industrial standard means it can sit in a panel with a 20 kA prospective fault current at the bus, no problem. ## Thermal derating — the real-world current The 25 A rating holds at 35 °C ambient. At 40 °C it's 23.8 A; at 50 °C it's 22.55 A; at 60 °C it's 21.2 A. Humidity derating also applies: max 95% RH up to 55 °C, then drops to 55% at 70 °C and 35% at 75 °C. Snap-on quick assembly system to DIN rail, any mounting position. IP20 with conductors connected; touch protection built in.","metaTitle":"Siemens 5SY4125-5 SENTRON MCB, 1P 25A, Char A, 10kA/20kA","metaDescription":"Siemens 5SY4125-5 SENTRON miniature circuit breaker, 1-pole, 25 A, tripping characteristic A, 10 kA (EN 60898) / 20 kA (IEC 60947-2). Active production. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["1-Pole MCB (DIN Rail)"],"specifications":{"Depth":"76 mm","Width":"18 mm","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","Halogen-Free":"Yes","Silicon-Free":"Yes","Number Of Poles":"1","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":"25 A","protection class IP":"IP20, with connected conductors","Overvoltage Category":"III","Combined Terminal Top":"Yes","Number Of Poles / Note":"1P","acc. to DIN EN 61346-2":"F","at 35 °C / rated value":"25 A","at 40 °C / rated value":"23.8 A","at 45 °C / rated value":"23.18 A","at 50 °C / rated value":"22.55 A","at 55 °C / rated value":"21.88 A","at 60 °C / rated value":"21.2 A","Combined Terminal Bottom":"Yes","Suitability For Operation":"Mechanical engineering / industry","Number Of Modular Width Units":"1","Tripping Characteristic Class":"A","acc. to EN 60898 / rated value":"10 kA","Position / Of Power Supply Cord":"Any","acc. to IEC 60947-2 / rated value":"20 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":"$68.84","priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=50359&mlfb=5SY4125-5","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SY4125-5/alternatives.json"},"ai":{"faq":[{"question":"How do I get current pricing and availability for 5SY4125-5?","answer":"Submit an RFQ through this listing. The part is sourced to order via independent distribution; availability and current pricing are confirmed at quote time."},{"question":"Will 5SY4125-5 drop into a panel that was specified around 5SY4140-7 without rewiring?","answer":"Yes — both are 1-pole SENTRON MCBs, 18 mm wide, same DIN-rail snap-on mounting. The 5SY4125-5 is 25 A characteristic A; the 5SY4140-7 is 40 A characteristic A. Same footprint, same terminal layout, same busbar pitch. No rewiring needed for the swap, but verify the load current and cable sizing for the lower rating."},{"question":"What compliance documentation does this brand provide for 5SY4125-5?","answer":"The SENTRON series carries IEC/EN 60898 and IEC 60947-2 certifications. The part is halogen-free and silicon-free. For specific RoHS/REACH declarations, request the manufacturer's compliance certificate — it's typically available per batch."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY4125-5","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/5SY4125-5 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}