{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SJ4125-8HG42","brand":"Siemens","brandSlug":"siemens","productSlug":"5SJ4125-8HG42","canonicalUrl":"https://aoctrl.com/siemens/5SJ4125-8HG42","factsUrl":"https://aoctrl.com/api/mcp/products/5SJ4125-8HG42","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SJ4125-8HG42 miniature circuit breaker, 1-pole, D tripping characteristic, 10 kA (EN 60898) / 15 kA (IEC 60947-2), 400 V AC / 60 V DC.","salesMarkdown":"The Siemens SENTRON 5SJ4125-8HG42 is a 1-pole miniature circuit breaker with a D tripping characteristic, rated 10 kA breaking capacity per EN 60898 and 15 kA per IEC 60947-2. That D-curve means it's built for loads with high inrush — think motor starters, transformers, or welding equipment — where the magnetic trip holds off until about 10–20 times rated current, so nuisance trips don't pull a line down on startup. The 15 kA rating under IEC 60947-2 gives you industrial-grade fault clearing; the 10 kA under EN 60898 covers the residential/commercial side. It's rated 400 V AC and 60 V DC, so it handles standard panel voltages and some DC control circuits. Sealable — you can lock the handle position with a padlock for lockout/tagout. Vibration resistance is 50 m/s² at 25–150 Hz and 60 m/s² at 35 Hz (4 seconds). Suitable for mechanical engineering and industrial environments per the manufacturer's suitability note.","metaTitle":"Siemens 5SJ4125-8HG42 SENTRON MCB, 1P D-curve, 10 kA","metaDescription":"Siemens SENTRON 5SJ4125-8HG42 miniature circuit breaker, 1-pole, D tripping characteristic, 10 kA per EN 60898, 15 kA per 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":"70 mm","Width":"18 mm","title":"5SJ4125-8HG42","Height":"121 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","description":"Circuit breaker 10kA, 1-pole, D, 25A according to UL 489-277V","Halogen-Free":"Yes","Silicon-Free":"Yes","Design Of Pole":"1P","Number Of Poles":"1","lifecycle_stage":"current","Fastening Method":"on standard mounting rail","Mounting Position":"any","at AC rated value":"400 V","at DC rated value":"60 V","Installation Depth":"70 mm","Product Brand Name":"SENTRON","Degree Of Pollution":"3","Product Designation":"Miniature circuit breakers","protection class IP":"IP20, with connected conductors, IP 40 in the handle range","Overvoltage Category":"3","Tunnel Terminals Top":"No","Vibration Resistance":"50 m/s² at 25 to 150Hz and 60m/s² at 35Hz (4sec)","Combined Terminal Top":"Yes","Design Of The Product":"Miniature circuit-breaker 5SJ4","Product Function Note":"Terminal tightening torque for Cu, 60/75°C; 3.5Nm/31lb.in","Tunnel Terminals Bottom":"No","Combined Terminal Bottom":"Yes","Suitability For Operation":"Mechanical engineering / industry","at DC rated value maximum":"60 V","Neutral Conductor Switching":"No","Number Of Modular Width Units":"1","Position Of Power Supply Cord":"Any","Tripping Characteristic Class":"D","according to EN 60898 rated value":"10 kA","Ambient Temperature During Operation":"max. 95% humidity","Supply Voltage Frequency Rated Value":"50 Hz","according to IEC 60947-2 rated value":"15 kA","installation environment regarding EMC":"Suitable for environment B (immunity to interference not applicable)","insulation voltage (Ui) at AC rated value":"440 V","Value Range Of The Supply Voltage Frequency":"50/60 Hz","vibration resistance according to IEC 60068-2-6":"±1 mm at 5 to 25 Hz; 50 m/s² at 25 to 150 Hz","Mechanical Service Life (Operating Cycles) Typical":"10 000","Product Extension Installable Supplementary Devices":"Yes","Tightening Torque With Screw-Type Terminals Maximum":"3.5 N·m","power loss [W] for rated value of the current at AC in hot operating state per pole":"2.9 W"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$98.98","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/62d6e36343aaa9b35ec7dc30f4594ad4.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=256050&mlfb=5SJ4125-8HG42"},"ai":{"faq":[{"question":"What is the breaking capacity of this breaker?","answer":"10 kA per EN 60898 and 15 kA per IEC 60947-2. The higher IEC rating applies in industrial installations where the prospective fault current is greater."},{"question":"What is the tripping characteristic and what loads is it for?","answer":"D-curve — magnetic trip threshold is roughly 10–20 times rated current. It's intended for loads with high inrush, such as motors, transformers, or welding equipment, to avoid nuisance tripping on startup."},{"question":"What are the mounting dimensions?","answer":"18 mm wide (1 modular unit), 70 mm deep, 121 mm high. Snaps onto standard 35 mm DIN rail; any mounting position is allowed."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SJ4125-8HG42","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/5SJ4125-8HG42 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}}