{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY7540-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY7540-8","canonicalUrl":"https://aoctrl.com/siemens/5SY7540-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SY7540-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY7 series miniature circuit breaker, order code 5SY7540-8, 40 A rated, D tripping characteristic, 1P+N, 15 kA (EN 60898) / 20 kA (IEC 60947-2) breaking capacity, 230 V AC.","salesMarkdown":"The Siemens 5SY7540-8 is a SENTRON miniature circuit breaker (MCB) with a D tripping characteristic, rated 40 A at 230 V AC. The 1P+N pole configuration (2-pole width, 36 mm) switches the phase and provides overcurrent protection on the phase only; the neutral is switched but not protected. Breaking capacity is 15 kA per EN 60898 and 20 kA per IEC 60947-2. The higher 20 kA IEC rating gives additional headroom for industrial panels specified to IEC 60947-2, where the breaker is treated as a circuit-breaker for industrial application rather than a household MCB. ## Deployment context The 36 mm width (2 width units) and 70 mm installation depth fit standard distribution boards and industrial enclosures. Terminal capacity accepts solid or stranded conductors from 0.75 to 35 mm², with combined top and bottom terminals for through-wiring or daisy-chaining. Rated for ambient temperatures from -40 to +70 °C, with derating above 55 °C per the humidity/temperature influence table.","metaTitle":"Siemens 5SY7540-8 SENTRON MCB, 40A D-Curve 2-Pole 15kA","metaDescription":"Siemens 5SY7540-8 SENTRON miniature circuit breaker, 40 A rated, D tripping characteristic, 1P+N, 15 kA (EN 60898) / 20 kA (IEC 60947-2) breaking capacity. Current lifecycle stage.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["1-Pole MCB (DIN Rail)"],"specifications":{"Depth":"76 mm","Solid":"0.75 ... 35 mm²","Width":"36 mm","Height":"90 mm","Sealable":"Yes","Stranded":"0.75 ... 35 mm²","Rated Value":"50/60 Hz","Halogen-Free":"Yes","Silicon-Free":"Yes","Mounting type":"Quick assembly system","During Storage":"-40 ... +75 °C","Number of poles":"2","Type of voltage":"AC","lifecycle_stage":"current","Mounting position":"any","Installation depth":"70 mm","Product brand name":"SENTRON","Ambient temperature":"-40 ... +70 °C","Product designation":"Miniature circuit breaker","Protection class IP":"IP20, with connected conductors","at AC / rated value":"230 V","Overvoltage category":"III","Combined Terminal Top":"Yes","Number of width units":"2","Number of poles / Note":"1P+N","acc. to DIN EN 61346-2":"F","acc. to DIN EN 81346-2":"F","Combined Terminal Bottom":"Yes","circuit-breaker / Design":"5SY7","Suitability for operation":"Mechanical engineering / industry","Current / at AC / rated value":"40 A","Tripping characteristic class":"D","at DC / rated value / maximum":"72 V","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","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","Tightening torque / with screw-type terminals":"2.5 ... 3.5 N·m","Product function / neutral conductor switching":"Yes","with single-phase operation / at AC / rated value":"250 V","Mechanical service life (switching cycles) / typical":"10 000","Tightening torque [lbf·in] / with screw-type terminals":"22 ... 31 lbf·in","AWG number / as coded connectable conductor cross section":"18 ... 4"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/ea9a5a496a526d38c64a76df41dd2a8a.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=29344&mlfb=5SY7540-8","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SY7540-8/alternatives.json"},"ai":{"faq":[{"question":"What is the closest functional second-source for 5SY7540-8?","answer":"The closest peer in the same SENTRON 5SY7 family is 5SY7140-8CC. Both are 40 A D-curve MCBs, but 5SY7140-8CC is a 1-pole (1P) unit occupying 18 mm width, whereas 5SY7540-8 is 1P+N (2-pole width, 36 mm) with a switched neutral. They are not drop-in interchangeable — the pole count and width differ. For a 1P+N application, 5SY7540-8 is the correct form, fit, and function."},{"question":"What compliance documentation does Siemens provide for 5SY7540-8?","answer":"The breaker carries ratings per EN 60898 (15 kA) and IEC 60947-2 (20 kA), and a UL 1077 / CSA C22.2 No.235 rating at 5 kA. Overvoltage category III. The SENTRON series is typically supplied with CE, UKCA, and EAC declarations; RoHS and REACH compliance documentation is available from Siemens upon request."},{"question":"Where can I buy 5SY7540-8 and how is it quoted?","answer":"Sourced and quoted to order against an RFQ through independent industrial-automation distribution. Availability and current pricing are confirmed at quote time — no stock count or price is published here."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY7540-8","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/5SY7540-8 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}}