{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"A9N21399","brand":"Schneider Electric","brandSlug":"schneider","productSlug":"A9N21399","canonicalUrl":"https://aoctrl.com/schneider/A9N21399","factsUrl":"https://aoctrl.com/api/mcp/products/A9N21399","rawCanonicalId":null},"summary":{"shortDescription":"Schneider Electric ProDis DT40 miniature circuit-breaker, A9N21399, 32 A, 3P, curve D, 6 kA Icn / 10 kA Icu, clip-on DIN rail mount.","salesMarkdown":"The Schneider Electric A9N21399 is a DT40 miniature circuit-breaker from the ProDis range, rated 32 A with 3 protected poles and a D tripping curve. The D curve means magnetic trip occurs at 10 to 14 times the rated current (10–14 x In), so it handles high inrush loads like motor starters and small transformers without nuisance tripping — that is the main reason to pick D over B or C in a distribution board feeding inductive equipment. Breaking capacity is 6000 A Icn at 400 V AC per EN/IEC 60898-1, and 10 kA Icu at 400–415 V AC per IEC 60947-2. The 78 mm depth and 81 mm height leave clearance for standard enclosure depths. Clip-on DIN rail mount means it snaps directly into a 35 mm rail inside a distribution board or control panel. IP20 finger protection (IEC 60529) is standard for enclosed panels — no special sealing needed.","metaTitle":"Schneider Electric A9N21399 DT40 MCB, 32 A, 3P, Curve D, 6 k","metaDescription":"Schneider Electric A9N21399 DT40 miniature circuit-breaker, 32 A rated, 3-pole, curve D, 6 kA Icn breaking capacity. Dual-rated to EN/IEC 60898-1 and 60947-2. Clip-on DIN rail moun","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Obsolete","categoryPath":["Miniature Circuit Breakers (MCB)"],"specifications":{"Depth":"78 mm","Range":"Prodis","Width":"54 mm","Colour":"White","Height":"81 mm","Standards":"EN/IEC 60898-1 EN/IEC 60947-2","Curve code":"D","9 Mm Pitches":"6","Control type":"Toggle","Network type":"AC","Product name":"DT40","Mounting mode":"Clip-on","Quality labels":"NF","Tropicalisation":"2 conforming to IEC 60068-1","lifecycle_stage":"current","Limitation class":"3 conforming to EN/IEC 60898-1","Local signalling":"ON/OFF indication","Mounting support":"DIN rail","Pollution degree":"3 conforming to IEC 60947-2","Range of product":"ProDis","Breaking capacity":"6000 A Icn at 400 V AC 50 Hz conforming to EN/IEC 60898-1 10 kA Icu at 400...415 V AC 50 Hz conforming to IEC 60947-2","Device short name":"DT40N","Network frequency":"50 Hz","Poles description":"3P","Relative humidity":"95 % at 55 °C","Tightening torque":"2 N.m","Device application":"Distribution","Operating altitude":"2000 m","[In] rated current":"32 A","Trip unit technology":"Thermal-magnetic","Electrical durability":"10000 cycles","Mechanical durability":"20000 cycles","Wire stripping length":"13 mm","Connections - terminals":"Tunnel type terminals downstream 0.33...10 mm² flexible Tunnel type terminals downstream 0.75...16 mm² rigid Tunnel type terminals upstream 0.33...10 mm² flexible Tunnel type terminals upstream 0.75...16 mm² rigid","IP degree of protection":"IP20 conforming to IEC 60529","Magnetic tripping limit":"10...14 x In","Earth-leakage protection":"Separate block","Number of protected poles":"3","Product or component type":"Miniature circuit-breaker","Suitability for isolation":"Yes","Contact position indicator":"Yes","Locking options description":"Padlocking device","[Ui] rated insulation voltage":"440 V AC 50 Hz","[Ue] rated operational voltage":"400 V AC 50 Hz between phases","Ambient air temperature for storage":"-40...70 °C","Ambient air temperature for operation":"-25...70 °C","[Ics] rated service breaking capacity":"6000 A 100 % x Icn at 400 V AC 50 Hz conforming to EN/IEC 60898-1 7.5 kA 75 % x Icu at 400 V AC 50 Hz conforming to IEC 60947-2","[Uimp] rated impulse withstand voltage":"4 kV conforming to IEC 60947-2"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/c1f774f9026fcbe9298721618994110b.pdf","sourceUrl":"https://www.se.com/uk/en/product/A9N21399/dt40-circuit-breaker-dt40n-3p-32a-d-curve/","alternativesUrl":"https://aoctrl.com/api/mcp/products/A9N21399/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy the A9N21399 and get a price?","answer":"The A9N21399 is sourced to order against an RFQ through independent distribution. Submit an RFQ for current availability and pricing — confirmed at quote time."},{"question":"What is the breaking capacity of the A9N21399?","answer":"The A9N21399 has a breaking capacity of 6000 A Icn at 400 V AC per EN/IEC 60898-1, and 10 kA Icu at 400–415 V AC per IEC 60947-2. The 10 kA Icu rating is the industrial fault-interruption figure."},{"question":"What does the D curve mean on this MCB?","answer":"The D curve means magnetic tripping occurs at 10 to 14 times the rated current (10–14 x In). This is designed for loads with high inrush current, such as motor starters, small transformers, and welding equipment — it avoids nuisance trips that a B or C curve would cause on those loads."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/schneider/A9N21399","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/schneider/A9N21399 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}}