{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SJ4108-8HG40","brand":"Siemens","brandSlug":"siemens","productSlug":"5SJ4108-8HG40","canonicalUrl":"https://aoctrl.com/siemens/5SJ4108-8HG40","factsUrl":"https://aoctrl.com/api/mcp/products/5SJ4108-8HG40","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SJ4 series, miniature circuit breaker, 1-pole, 8 A rated at AC, D tripping characteristic, 18 mm width, DIN rail mount.","salesMarkdown":"## What it is and where it fits The Siemens 5SJ4108-8HG40 is a SENTRON miniature circuit breaker (MCB) from the 5SJ4 family, designed for 1-pole protection of branch circuits at a rated 8 A AC. The D tripping characteristic means it tolerates high inrush currents — typically used for motor, transformer, or lighting loads where the starting surge would nuisance-trip a B or C curve. It snaps onto standard DIN rail (35 mm) and occupies a single modular width unit (18 mm), so it fits tight panel layouts without crowding adjacent breakers. ## Thermal derating and real-world current At 30 °C and 40 °C the breaker holds its full 8 A rating. At 45 °C it derates to 7.8 A, at 50 °C to 7.6 A, at 55 °C to 7.4 A, and at 60 °C to 7.2 A. If your panel ambient runs hot — say, a sealed enclosure near a process line — size the load to the derated value, not the nameplate 8 A. The operating range spans -40 °C to 75 °C, which covers most industrial environments from cold storage to near-oven zones.","metaTitle":"Siemens 5SJ4108-8HG40 SENTRON MCB, 1P, 8A, D Curve","metaDescription":"Siemens SENTRON 5SJ4108-8HG40 miniature circuit breaker, 1-pole, 8 A rated, D tripping characteristic. DIN rail mount, 18 mm wide. Active production. Quoted 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":"5SJ4108-8HG40","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","description":"Miniature circuit breaker 240 V 14kA, 1-pole, D, 8A, D=70 mm according to UL 489, equal polarity","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","Installation Depth":"70 mm","Product Brand Name":"SENTRON","Degree Of Pollution":"3","Product Designation":"Miniature circuit breakers","at AC / rated value":"8 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":"8 A","at 40 °C / rated value":"8 A","at 45 °C / rated value":"7.8 A","at 50 °C / rated value":"7.6 A","at 55 °C / rated value":"7.4 A","at 60 °C / rated value":"7.2 A","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":"1","Tripping Characteristic Class":"D","at DC / rated value / maximum":"60 V","Position / Of Power Supply Cord":"Any","according to EN 60898 / rated value":"10 kA","supply voltage / at AC / rated value":"400 V","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)","Type Of Voltage / Of The Operating Voltage":"AC/DC","insulation voltage (Ui) / at AC / rated value":"440 V","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 (Switching Cycles) / Typical":"10 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$77.23","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/a8c044e12c61c590a7789606d5dfbdbc.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=6166&mlfb=5SJ4108-8HG40"},"ai":{"faq":[{"question":"How do I get current pricing and availability for 5SJ4108-8HG40?","answer":"Submit an RFQ through this listing. The part is sourced to order through independent distribution; pricing and stock levels are confirmed at quote time."},{"question":"What is 5SJ4108-8HG40's listed depth (70 mm) on this component line?","answer":"The depth is 70 mm, with an installation depth of 70 mm. Width is 18 mm (one modular unit), height is 90 mm."},{"question":"What compliance documentation does this brand provide for 5SJ4108-8HG40 (RoHS, REACH, UL, IEC)?","answer":"The breaker is designed to EN 61346-2 and IEC 81346-2 (both coded F for protective devices). It carries pollution degree 3 and overvoltage category 3 ratings. The SENTRON series typically provides CE, UL, and CSA certifications; confirm specific documentation with the RFQ."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SJ4108-8HG40","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/5SJ4108-8HG40 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}}