{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"A9N21420","brand":"Schneider Electric","brandSlug":"schneider","productSlug":"A9N21420","canonicalUrl":"https://aoctrl.com/schneider/A9N21420","factsUrl":"https://aoctrl.com/api/mcp/products/A9N21420","rawCanonicalId":null},"summary":{"shortDescription":"Schneider Electric ProDis DT40N, miniature circuit breaker, D curve, 40 A, 3P+N, 6 kA Icn / 10 kA Icu, clip-on DIN rail mount, IP20.","salesMarkdown":"Breaking capacity is dual-rated: 6 kA Icn per EN/IEC 60898-1 for general distribution, and 10 kA Icu per IEC 60947-2 for industrial panel duty. Clip-on mounting to DIN rail, 54 mm wide (6 x 9 mm pitches), with tunnel terminals accepting up to 16 mm² rigid or 10 mm² flexible on both line and load sides. IP20 finger-safe front; the 78 mm depth leaves clearance behind a standard 100 mm deep enclosure gland plate. ## Dual-standard certification and deployment context Rated to both EN/IEC 60898-1 (household / similar installation MCB standard) and EN/IEC 60947-2 (industrial low-voltage switchgear standard). This dual rating is the key spec for a panel builder: the 60898-1 side covers the branch circuit protection for a fixed load, while the 60947-2 side covers the isolation and fault-breaking duty inside an industrial enclosure. The 2000 m operating altitude covers most industrial sites; above that, dielectric strength derates per the standard. ## D curve selection — what it means for the buyer The D curve (10–14 x In magnetic trip) is the deciding factor for fit. A 40 A D-curve MCB will pass the starting current of a 15 kW direct-on-line motor (typically 6–8 x FLA for 5–10 seconds) without tripping, where a C curve (5–10 x In) might nuisance-trip on a hard-starting load.","metaTitle":"Schneider Electric A9N21420 DT40N MCB, D Curve 40 A 3P+N, 6","metaDescription":"Schneider Electric A9N21420 DT40N miniature circuit breaker. D curve, 40 A rated, 3P+N, 6 kA (Icn) / 10 kA (Icu). Dual-rated EN/IEC 60898-1 & 60947-2. Current lifecycle. Available","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","Neutral position":"Left","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 + N","Relative humidity":"95 % at 55 °C","Tightening torque":"2 N.m","Device application":"Distribution","Operating altitude":"2000 m","[In] rated current":"40 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":"400 V AC 50 Hz","[Ue] rated operational voltage":"230 V AC 50 Hz between phase and neutral 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/125a905df19ac91908420ed81b7a4d92.pdf","sourceUrl":"https://www.se.com/uk/en/product/A9N21420/dt40-circuit-breaker-dt40n-3p-+-n-40a-d-curve/","alternativesUrl":"https://aoctrl.com/api/mcp/products/A9N21420/alternatives.json"},"ai":{"faq":[{"question":"What standards does the A9N21420 comply with?","answer":"Dual-rated to EN/IEC 60898-1 and EN/IEC 60947-2, with pollution degree 3 and tropicalisation level 2 per IEC 60068-1."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/schneider/A9N21420","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/A9N21420 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}}