{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY7540-6","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY7540-6","canonicalUrl":"https://aoctrl.com/siemens/5SY7540-6","factsUrl":"https://aoctrl.com/api/mcp/products/5SY7540-6","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY7540-6 miniature circuit breaker, 40 A, B-curve, 2-pole (1P+N), 15 kA (EN 60898) / 20 kA (IEC 60947-2), 2 MW, IP20, current production.","salesMarkdown":"## Siemens 5SY7540-6 SENTRON MCB — 40 A B-Curve, 2-Pole, 15/20 kA The Siemens 5SY7540-6 is a SENTRON miniature circuit breaker rated 40 A with a B-curve tripping characteristic, configured as 2-pole (1P+N) in a 2-module-width (36 mm) DIN-rail housing. The B-curve (3–5× In) means it trips fast on short-circuit but tolerates moderate inrush — a fit for resistive and lighting loads rather than motor circuits. The 40 A rating holds at 35 °C ambient; derate to 36.28 A at 45 °C, 34.96 A at 50 °C, 33.6 A at 55 °C, and 32.16 A at 60 °C (–). The 15 kA (EN 60898) and 20 kA (IEC 60947-2) breaking capacities are the maximum fault currents the MCB can safely interrupt — verify the supply-side SCCR at the distribution board. The 2-pole 1P+N configuration switches the line conductor and provides a switched neutral disconnection — required in some regional wiring rules for final circuits. Operating temperature spans -40 to 75 °C, with humidity limits of 95% up to 55 °C, tapering to 35% at 75 °C. ## Construction and compliance Halogen-free and silicon-free construction reduces corrosive off-gassing in a fire — relevant for clean-room or enclosed panel environments. Touch protection is integral. Energy limitation class 3 means the let-through energy is limited, reducing downstream equipment stress during a fault.","metaTitle":"Siemens 5SY7540-6 SENTRON MCB, 40A B-Curve 2-Pole 15kA","metaDescription":"Siemens 5SY7540-6 SENTRON miniature circuit breaker, 40 A rated, B-curve, 2-pole (1P+N), 15 kA per EN 60898, 20 kA per IEC 60947-2. Current 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":"76 mm","Width":"36 mm","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","Halogen-Free":"Yes","Silicon-Free":"Yes","Number Of Poles":"2","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":"40 A","protection class IP":"IP20, with connected conductors","Overvoltage Category":"III","Combined Terminal Top":"Yes","Number Of Poles / Note":"1P+N","acc. to DIN EN 61346-2":"F","Energy Limitation Class":"3","at 35 °C / rated value":"40 A","at 45 °C / rated value":"36.28 A","at 50 °C / rated value":"34.96 A","at 55 °C / rated value":"33.6 A","at 60 °C / rated value":"32.16 A","Combined Terminal Bottom":"Yes","Suitability For Operation":"Mechanical engineering / industry","Number Of Modular Width Units":"2","Tripping Characteristic Class":"B","acc. to EN 60898 / rated value":"15 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":"Yes","operating voltage / at DC / rated value / maximum":"72 V","with single-phase operation / at AC / rated value":"250 V","Mechanical Service Life (Operating Cycles) / Typical":"10 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/2ce10a91afc9e1f96ad51b93fa38d16d.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=387541&mlfb=5SY7540-6","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SY7540-6/alternatives.json"},"ai":{"faq":[{"question":"What is the breaking capacity of 5SY7540-6?","answer":"15 kA per EN 60898 and 20 kA per IEC 60947-2. The higher figure applies when the MCB is used in industrial applications per the IEC standard."},{"question":"What is the temperature derating for 5SY7540-6?","answer":"Rated 40 A at 35 °C, derated to 36.28 A at 45 °C, 34.96 A at 50 °C, 33.6 A at 55 °C, and 32.16 A at 60 °C (–)."},{"question":"Where can I buy 5SY7540-6 and get a price?","answer":"Sourced through independent distribution. Submit an RFQ for current availability and pricing — confirmed at quote time."},{"question":"Will 5SY7540-6 drop into a panel that was specified around 5SY4116-6CC?","answer":"Both are 2-module-width (36 mm) SENTRON MCBs on the same DIN-rail footprint, so mechanical fit is the same. However, the 5SY7540-6 is a 40 A B-curve 2-pole (1P+N) unit, while the 5SY4116-6CC is a different rating/curve — verify the circuit's ampacity and trip characteristic before swapping."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY7540-6","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/5SY7540-6 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}}