{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"XT4LU3040AFF00NXXX","brand":"ABB","brandSlug":"abb","productSlug":"XT4LU3040AFF00NXXX","canonicalUrl":"https://aoctrl.com/abb/XT4LU3040AFF00NXXX","factsUrl":"https://aoctrl.com/api/mcp/products/XT4LU3040AFF00NXXX","rawCanonicalId":null},"summary":{"shortDescription":"ABB XT4L series molded case circuit breaker, 250 A frame, TMF 40-400 A adjustable thermal-magnetic trip, 3-pole, fixed front terminals, UL/CSA rated.","salesMarkdown":"ABB XT4LU3040AFF00NXXX is a 3-pole molded case circuit breaker from the XT4L series, built on a 250 A frame with a TMF (thermal-magnetic fixed) trip unit adjustable from 40 to 400 A. The TMF curve gives you a thermal element for overload protection and a magnetic element for short-circuit response — no electronic adjustments, just a fixed magnetic pickup that tracks the thermal setting. Fixed front terminals and UL/CSA listing mean it lands in North American panels without a terminal conversion. The 250 A frame provides the mechanical and thermal capacity to handle continuous currents up to that level, while the TMF trip unit lets you dial the overload protection between 40 and 400 A — meaning one breaker body covers a wide range of motor or feeder sizes. The magnetic short-circuit pickup is fixed at roughly 10× the thermal setting, so coordination with downstream breakers follows standard thermal-magnetic selectivity rules. UL/CSA listing certifies compliance with North American panel-building standards; the breaker is suitable for branch-circuit protection per NEC/CEC. ## Deployment Context The fixed front terminals accept bus bars or cable lugs; plan for 3-pole wiring with a neutral bar if the circuit requires it. The TMF trip is field-adjustable via a dial on the front face — no power-down needed for adjustment, but the breaker must be in the OFF position to change the setting.","metaTitle":"ABB XT4LU3040AFF00NXXX XT4L 250 A MCCB, TMF 40-400 A, 3P","metaDescription":"ABB XT4LU3040AFF00NXXX XT4L molded case circuit breaker, 250 A frame, TMF 40-400 A trip, 3-pole. Lifecycle stage current. Sourced to order against RFQ.","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/XT4LU3040AFF00NXXX/alternatives.json"},"ai":{"faq":[{"question":"How do I get pricing and availability for XT4LU3040AFF00NXXX?","answer":"Sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time."},{"question":"What does the description XT4L 250 TMF 40-400 3P F F UL/CSA mean?","answer":"It decodes as: XT4L series, 250 A frame, TMF (thermal-magnetic fixed) trip unit adjustable 40-400 A, 3-pole, fixed front terminals, fixed front terminals (listed twice in the source string), UL/CSA rated."},{"question":"What compliance documentation is available for this breaker?","answer":"The UL/CSA listing in the description confirms compliance with North American safety standards. For RoHS, REACH, and detailed certifications, the manufacturer provides compliance documentation on request."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/abb/XT4LU3040AFF00NXXX","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/XT4LU3040AFF00NXXX 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}}