{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY6340-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY6340-8","canonicalUrl":"https://aoctrl.com/siemens/5SY6340-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SY6340-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY6 series, D-curve miniature circuit breaker, 3-pole, 40 A, 400 V AC, 6 kA (EN 60898) / 10 kA (IEC 60947-2), 3 MW wide, IP20, snap-on DIN rail.","salesMarkdown":"## SENTRON 5SY6340-8 — D-curve 40 A, 3-pole MCB for industrial branch circuits Siemens SENTRON 5SY6 series miniature circuit breaker, D tripping characteristic, rated 40 A at 400 V AC, 3 poles. Occupies 3 width units (54 mm) on DIN rail. At DC, the IEC 60947-2 rating reaches 15 kA at 72 V. For UL 1077 / CSA C22.2 No. 235 applications, the interrupting rating is 5 kA. That spread means the same part covers IEC panels and UL-recognized supplementary protection — one BOM line for both regimes. ## D-curve selectivity and coordination in the panel The D-curve holds magnetic trip to 10–20× rated current (400–800 A instantaneous). That delay lets downstream motor-starting inrush pass without clearing the branch. Upstream, a higher-rated SENTRON or SITOR fuse must coordinate for full selectivity — typical rule: upstream device rated ≥ 1.6× the 40 A for overload discrimination, and the instantaneous thresholds must not overlap. The IP20 rating (with conductors connected) means it belongs inside a closed enclosure, not in washdown or outdoor exposure. ## Mechanical integration — DIN rail, 3 MW, any position Any mounting position is permitted — horizontal, vertical, or inverted — no derating required for orientation. The 54 mm width (3 module widths) matches the standard 18 mm/module grid; adjacent breakers or accessories (shunt trip, auxiliary switch) occupy adjacent slots without special spacing. Installation depth is 70 mm to the DIN rail surface; overall depth 76 mm includes the toggle and terminal screws. Ambient temperature range -40 °C to 75 °C, with derating for humidity: max 95% RH at 55 °C, 55% at 70 °C, 35% at 75 °C. That covers cold storage, unheated enclosures, and transformer cabinets.","metaTitle":"Siemens 5SY6340-8 SENTRON MCB, D-Curve 40A 3P 400V AC 6kA EN","metaDescription":"Siemens 5SY6340-8 SENTRON miniature circuit breaker, D-curve, 40 A, 3-pole, 400 V AC. Rated 6 kA per EN 60898, 10 kA per IEC 60947-2. Current production, sourced to order against R","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Miniature Circuit Breakers (MCB)"],"specifications":{"Depth":"76 mm","Width":"54 mm","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","Rated Value":"50/60 Hz","Halogen-Free":"Yes","Silicon-Free":"Yes","Mounting type":"Quick assembly system","Number of poles":"3","Type of voltage":"AC","lifecycle_stage":"current","Mounting position":"any","Installation depth":"70 mm","Product brand name":"SENTRON","Degree of pollution":"3","Product designation":"Miniature circuit breaker","Protection class IP":"IP20, with connected conductors","at AC / rated value":"400 V","Overvoltage category":"III","Combined Terminal Top":"Yes","Number of width units":"3","Number of poles / Note":"3P","acc. to DIN EN 61346-2":"F","acc. to DIN EN 81346-2":"F","Combined Terminal Bottom":"Yes","circuit-breaker / Design":"5SY6","Suitability for operation":"Mechanical engineering / industry","Tripping characteristic class":"D","at DC / rated value / maximum":"72 V","acc. to EN 60898 / rated value":"6 kA","Position / of power supply cord":"Any","acc. to IEC 60947-2 / rated value":"10 kA","Product feature / Touch protection":"Yes","Operating current / at AC / rated value":"40 A","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","Product function / neutral conductor switching":"No","with multi-phase operation / at AC / rated value":"440 V","with single-phase operation / at AC / rated value":"440 V","Mechanical service life (switching cycles) / typical":"10 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$110.74","priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=168624&mlfb=5SY6340-8","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SY6340-8/alternatives.json"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY6340-8","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/5SY6340-8 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}}