{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"XT5NU340ABFFBB0XXX","brand":"ABB","brandSlug":"abb","productSlug":"XT5NU340ABFFBB0XXX","canonicalUrl":"https://aoctrl.com/abb/XT5NU340ABFFBB0XXX","factsUrl":"https://aoctrl.com/api/mcp/products/XT5NU340ABFFBB0XXX","rawCanonicalId":null},"summary":{"shortDescription":"ABB XT5N 400 series, TMA 400-4000 A, 3-pole, fixed front terminals, UL listed, order code XT5NU340ABFFBB0XXX.","salesMarkdown":"The ABB XT5NU340ABFFBB0XXX is a 3-pole molded case circuit breaker from the XT5N 400 family, fitted with a TMA 400-4000 A electronic trip unit and fixed front terminals (FF). The UL listing is built into the base variant — the suffix confirms it. The TMA trip unit covers a 400–4000 A continuous current range, adjustable via the front dials. That makes it a feeder breaker sized for the main distribution board in an industrial plant, not a branch-circuit device. The 400 A frame is the smallest in the XT5N class, so the breaker body itself is rated for the full 400 A without needing a larger frame. ## What the TMA trip unit means for coordination The TMA is a solid-state trip offering adjustable long-time (Ir), short-time (Isd), and instantaneous (Ii) pickup, plus ground-fault protection if the neutral sensor is wired. For a site electrical engineer building a selective coordination study, the short-time delay band lets you set intentional delay so the feeder holds in for a downstream fault — provided the upstream breaker's instantaneous threshold is set above the feeder's let-through. The 400–4000 A range on the long-time dial gives enough headroom to match transformer or generator ratings without swapping the breaker frame.","metaTitle":"ABB XT5NU340ABFFBB0XXX XT5N 400 TMA 400-4000 3P FF UL, curre","metaDescription":"ABB XT5NU340ABFFBB0XXX XT5N 400 TMA 400-4000 3P FF UL. Lifecycle stage: current. Sourced to order against an RFQ. Quoted on request.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Molded Case Circuit Breakers (MCCB)"],"specifications":{"lifecycle_stage":"current"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":null,"alternativesUrl":"https://aoctrl.com/api/mcp/products/XT5NU340ABFFBB0XXX/alternatives.json"},"ai":{"faq":[{"question":"Who supplies XT5NU340ABFFBB0XXX and how is it quoted for volume purchases?","answer":"This part is sourced through independent distribution channels. It is quoted to order against an RFQ — submit a request for volume pricing and availability."},{"question":"What is the closest pin-compatible alternative to XT5NU340ABFFBB0XXX in this component family?","answer":"Within the XT5N 400 family, the same frame and terminal layout is shared across TMA, TMD, and electronic trip variants. The TMA 400-4000 A unit is the adjustable electronic version; a fixed thermal-magnetic TMD would be a lower-cost alternative if adjustability is not required, but pin compatibility depends on the exact terminal arrangement — verify the fixed-front (FF) terminal pattern matches your bus bar layout."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/abb/XT5NU340ABFFBB0XXX","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/abb/XT5NU340ABFFBB0XXX 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}}