{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY6340-6","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY6340-6","canonicalUrl":"https://aoctrl.com/siemens/5SY6340-6","factsUrl":"https://aoctrl.com/api/mcp/products/5SY6340-6","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY6340-6, 3-pole miniature circuit breaker, 40 A rated, B characteristic, 6 kA per EN 60898 / 10 kA per IEC 60947-2, 3 MW units, IP20.","salesMarkdown":"The 3-module-width footprint (54 mm) and 70 mm installation depth mean it fits the same cutout as any other 3-pole SENTRON MCB; no panel rework needed if you're swapping from another 3-pole unit in the same family. ## Derating and ambient temperature — the real-world current rating The 40 A nameplate rating holds at 35 °C ambient. Above that, the continuous current must be derated: 38.4 A at 40 °C, 37.6 A at 45 °C, 36.76 A at 50 °C, 35.92 A at 55 °C. If the panel runs hot — say, inside a non-ventilated enclosure near transformers or drives — size the upstream protection or load accordingly. The operating range is -40 °C to 75 °C, with humidity limits: max 95% RH up to 55 °C, then derated to 55% at 70 °C and 35% at 75 °C. That covers outdoor cabinets in cold climates and warm indoor switchgear rooms. ## Where it goes and what it guards This MCB is designed for AC circuits only — the operating voltage type is AC. Typical deployment is in sub-distribution boards for lighting, socket outlets, small HVAC units, and control transformers in mechanical engineering and industrial settings.","metaTitle":"Siemens 5SY6340-6 SENTRON MCB, 40 A B-Curve, 3-Pole","metaDescription":"Siemens 5SY6340-6 SENTRON miniature circuit breaker, 40 A rated, B tripping characteristic, 3-pole, 6 kA (EN 60898) / 10 kA (IEC 60947-2). Current production. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["3-Pole MCB (DIN Rail)"],"specifications":{"Depth":"76 mm","Width":"54 mm","title":"5SY6340-6","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","Standard":"IEC / EN 60898-1, IEC / EN 60947-2 / UL1077","description":"Miniature circuit breaker 400 V 6kA, 3-pole, B, 40A, D=70 mm","Halogen-Free":"Yes","Silicon-Free":"Yes","Design Of Pole":"3P","Number Of Poles":"3","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","at AC / rated value":"40 A","protection class IP":"IP20, with connected conductors","Overvoltage Category":"III","Combined Terminal Top":"Yes","Energy Limitation Class":"3","according to EN 61346-2":"F","at 35 °C / rated value":"40 A","at 40 °C / rated value":"38.4 A","at 45 °C / rated value":"37.6 A","at 50 °C / rated value":"36.76 A","at 55 °C / rated value":"35.92 A","Combined Terminal Bottom":"Yes","according to IEC 81346-2":"F","Suitability For Operation":"Mechanical engineering / industry","Number Of Modular Width Units":"3","Tripping Characteristic Class":"B","Position / Of Power Supply Cord":"Any","Product Feature / Touch Protection":"Yes","according to EN 60898 / rated value":"6 kA","according to IEC 60947-2 / rated value":"10 kA","Influence Of The Surrounding Temperature":"max. 95% to 55°C, max. 55% to 70°C, max. 35% to 75°C","Type Of Voltage / Of The Operating Voltage":"AC","at DC / according to IEC 60947-2 / rated value":"15 kA","Product Component / Neutral Conductor Switching":"No","with multi-phase operation / at AC / rated value":"440 V","operating voltage / at DC / rated value / maximum":"72 V","vibration resistance / according to IEC 60068-2-6":"±1mm at 5 to 25Hz; 50m/s² at 25 to 150Hz","with single-phase operation / at AC / rated value":"440 V","Mechanical Service Life (Switching Cycles) / Typical":"10 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$38.10","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/53bb2f6e85b4c53a81618ef81fed1968.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=220263&mlfb=5SY6340-6"},"ai":{"faq":[{"question":"What is the breaking capacity of 5SY6340-6?","answer":"6 kA per EN 60898 and 10 kA per IEC 60947-2 / UL1077. The higher figure applies when the MCB is used in an industrial distribution board rated under IEC 60947-2."},{"question":"Will 5SY6340-6 drop into a panel specified for 5SY4140-7?","answer":"Both are 3-pole SENTRON MCBs with the same 3 MW footprint (54 mm wide) and 70 mm installation depth. The 5SY6340-6 is rated 40 A B-curve; the 5SY4140-7 is a different rating or curve variant. Mechanically they interchange, but verify the load current and trip characteristic match your circuit design."},{"question":"Where can I buy 5SY6340-6?","answer":"Sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing confirmed at quote time."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY6340-6","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/5SY6340-6 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}}