The XT4NU3125AFF000XXX: The 250 A frame size means the breaker's physical housing and bus connections are rated for continuous currents up to 250 A, but the TMF trip unit's adjustable range of 125–1250 A lets you set the actual overload and short-circuit protection threshold within that band. The '3P F F' designation indicates three poles, fixed mounting (not plug-in or drawout), and fixed front terminals — so it bolts directly to a busbar or cable lug in a panel, with no accessory cradle.

ABB XT4NU3125AFF000XXX XT4N 250A TMF MCCB, 3P F F UL/CSA
ABB XT4N series, XT4NU3125AFF000XXX, 250 A frame TMF 125-1250 A, 3-pole, fixed, fixed, UL/CSA molded case circuit breaker.
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Frequently asked questions
What does the description XT4N 250 TMF 125-1250 3P F F UL/CSA mean?
It decodes as: XT4N series, 250 A frame, TMF (thermal-magnetic fixed) trip unit adjustable 125–1250 A, 3-pole, fixed mounting, fixed front terminals, UL/CSA certified.
Where can I buy XT4NU3125AFF000XXX and get current pricing?
This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time.