{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SJ4201-8HG42","brand":"Siemens","brandSlug":"siemens","productSlug":"5SJ4201-8HG42","canonicalUrl":"https://aoctrl.com/siemens/5SJ4201-8HG42","factsUrl":"https://aoctrl.com/api/mcp/products/5SJ4201-8HG42","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SJ4 miniature circuit breaker, 2-pole, 1 A rated current at AC, D tripping characteristic, 70 mm depth, 36 mm width, IP20/IP40.","salesMarkdown":"The Siemens 5SJ4201-8HG42 is a SENTRON 5SJ4 miniature circuit breaker with 2 poles, rated 1 A at AC and a D tripping characteristic. At 1 A, this is sized for small loads: a fractional-horsepower motor, a control transformer, or a single lighting branch. The 2-pole configuration handles single-phase 240 V or two legs of a three-phase system. Rated for 60 V DC maximum per pole, so it also works in DC control circuits up to that voltage. ## Thermal derating — what the 1 A rating actually delivers in a warm panel At 45 °C it derates to 0.97 A, at 50 °C to 0.9 A, at 55 °C still 0.9 A, and at 60 °C to 0.88 A. A 1 A D-curve MCB in a 60 °C environment will carry only 0.88 A continuously without tripping. That's a 12 % reduction; plan your load accordingly. Width is 36 mm (2 MW), depth 70 mm, height 121 mm. Installation depth matches the overall depth — no extra clearance needed behind the rail. Touch protection is built in, so accidental contact with live terminals is prevented when the breaker is installed in an enclosed panel.","metaTitle":"Siemens 5SJ4201-8HG42 SENTRON MCB, 2-Pole, 1 A, D Curve","metaDescription":"Siemens 5SJ4201-8HG42 SENTRON 2-pole miniature circuit breaker, 1 A rated current, D tripping characteristic, 70 mm depth, IP20/IP40. Active production, available to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["2-Pole MCB (DIN Rail)"],"specifications":{"Depth":"70 mm","Width":"36 mm","title":"5SJ4201-8HG42","Height":"121 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","description":"Circuit breaker 10kA, 2-pole, D, 1A according to UL 489-480Y/277V","Halogen-Free":"Yes","Silicon-Free":"Yes","Number Of Poles":"2","lifecycle_stage":"current","Fastening Method":"on standard mounting rail","Mounting Position":"any","Installation Depth":"70 mm","Product Brand Name":"SENTRON","Degree Of Pollution":"3","Product Designation":"Miniature circuit breakers","at AC / rated value":"1 A","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","according to EN 61346-2":"F","at 30 °C / rated value":"1 A","at 40 °C / rated value":"1 A","at 45 °C / rated value":"0.97 A","at 50 °C / rated value":"0.9 A","at 55 °C / rated value":"0.9 A","at 60 °C / rated value":"0.88 A","Combined Terminal Bottom":"Yes","according to IEC 81346-2":"F","Suitability For Operation":"Mechanical engineering / industry","Number Of Modular Width Units":"2","Tripping Characteristic Class":"D","at DC / rated value / maximum":"60 V","Position / Of Power Supply Cord":"Any","Product Feature / Touch Protection":"Yes","according to EN 60898 / rated value":"10 kA","supply voltage / at AC / rated value":"400 V","according to IEC 60947-2 / rated value":"15 kA","installation environment regarding EMC":"Suitable for environment B (immunity to interference not applicable)","Type Of Voltage / Of The Operating Voltage":"AC/DC","insulation voltage (Ui) / at AC / rated value":"440 V","Product Component / Neutral Conductor Switching":"No","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/b22711db93d4e05684a5cba070245dd0.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=407256&mlfb=5SJ4201-8HG42"},"ai":{"faq":[{"question":"Where can I buy 5SJ4201-8HG42 and get current pricing?","answer":"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 closest functional second-source to 5SJ4201-8HG42?","answer":"The Siemens 5SY4301-7CV is a 1 A, 2-pole MCB but with a C tripping characteristic. The D curve on the 5SJ4201-8HG42 handles higher inrush (motor/transformer loads) than the C curve. For a direct D-curve replacement, stick with the 5SJ4 family. The 5SY4301-7CV will not drop in without checking the load's inrush profile."},{"question":"What compliance documentation does Siemens provide for 5SJ4201-8HG42?","answer":"The MCB is designed to IEC/EN 60898-1 and carries CE marking. It is halogen-free and silicon-free. RoHS and REACH compliance documentation is available from Siemens on request."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SJ4201-8HG42","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/5SJ4201-8HG42 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}}