{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SL4240-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SL4240-8","canonicalUrl":"https://aoctrl.com/siemens/5SL4240-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SL4240-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SL4240-8 miniature circuit breaker, 2-pole, D-curve, 40 A, 10 kA at 400 V AC, 2-module-width (36 mm).","salesMarkdown":"The Siemens SENTRON 5SL4240-8 is a 2-pole miniature circuit breaker rated 40 A at 400 V AC, with a D tripping characteristic and a 10 kA breaking capacity per EN 60898 and IEC 60947-2. The D-curve means it tolerates inrush currents up to 10–20× rated — designed for motor, transformer, or welding loads that draw a heavy start surge without nuisance tripping. Temperature derating is built in: at 40 °C ambient the continuous rating drops to 37.89 A, at 45 °C to 36.8 A, and at 55 °C to 34.47 A. If your panel runs hot, size the upstream breaker accordingly — the 40 A nameplate is only valid at 30 °C. The 5SL4240-8 occupies 2 modular width units (36 mm) on a DIN rail, with a depth of 76 mm and an installation depth of 70 mm. Snap-on mounting in any position — no orientation restrictions. The sealable design lets you lock the toggle position for tamper-proof installations in schools or common areas.","metaTitle":"Siemens 5SL4240-8 SENTRON MCB, 2P D 40 A, 10 kA, 400 V","metaDescription":"Siemens SENTRON 5SL4240-8 miniature circuit breaker, 2-pole, D-curve, 40 A, 10 kA breaking capacity at 400 V AC. Current production. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["2-Pole MCB (DIN Rail)"],"specifications":{"Depth":"76 mm","Width":"36 mm","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","Halogen-Free":"Yes","Silicon-Free":"Yes","Design Of Pole":"2P","Number Of Poles":"2","lifecycle_stage":"current","Mounting Position":"any","Installation Depth":"70 mm","Product Brand Name":"SENTRON","Degree Of Pollution":"2","Product Designation":"Miniature circuit breaker","at AC / rated value":"40 A","protection class IP":"IP20, with connected conductors","Overvoltage Category":"III","Energy Limitation Class":"3","according to EN 61346-2":"F","at 30 °C / rated value":"40 A","at 40 °C / rated value":"37.89 A","at 45 °C / rated value":"36.8 A","at 55 °C / rated value":"34.47 A","according to IEC 81346-2":"F","Suitability For Operation":"Residential buildings/infrastructure","Number Of Modular Width Units":"2","Tripping Characteristic Class":"D","at DC / rated value / maximum":"72 V","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":"10 kA","Type Of Voltage / Of The Operating Voltage":"AC","with multi-phase operation / at AC / maximum":"440 V","Product Component / Neutral Conductor Switching":"No","with multi-phase operation / at AC / rated value":"440 V","Mechanical Service Life (Switching Cycles) / Typical":"10 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/77b3fe62c514fdaf9d52ccbc99f9d87c.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=88597&mlfb=5SL4240-8","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SL4240-8/alternatives.json"},"ai":{"faq":[{"question":"How do I get current pricing and availability for 5SL4240-8?","answer":"Submit an RFQ through the storefront. The part is sourced to order through independent distribution; pricing and stock are confirmed at quote time."},{"question":"What is 5SL4240-8's listed depth?","answer":"The depth is 76 mm, with an installation depth of 70 mm."},{"question":"What is 5SL4240-8's listed width?","answer":"The width is 36 mm, which is 2 modular width units on a standard DIN-rail panel."},{"question":"Will 5SL4240-8 drop into a panel specified around 5SL4120-7CC without rewiring?","answer":"Both are 2-pole, 36 mm wide MCBs on the same DIN-rail footprint, so the mechanical fit is identical. The difference is the rating: 5SL4240-8 is a 40 A D-curve; 5SL4120-7CC is a lower-current variant (check its rating). Rewiring depends on the load — if the existing circuit is sized for a lower ampacity, you cannot simply swap to a 40 A breaker without verifying the conductor and load."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SL4240-8","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/5SL4240-8 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}}