Product introduction
The ABB XT3NU4225AFJ000XXX is a molded case circuit breaker from the XT3N 225 frame, fitted with a TMF 225-2250 A thermal-magnetic trip unit. It is a 4-pole device with front-front terminals, certified to UL and CSA standards. This breaker is sized for distribution and motor branch-circuit protection in industrial and commercial panels where a 225 A frame with adjustable thermal-magnetic characteristics is called for.
What the ratings mean for the BOM
The TMF 225-2250 A trip covers a continuous current range from 225 A up to 2250 A — the thermal element handles overloads, the magnetic element clears short-circuits. The 4-pole configuration suits three-phase plus neutral or switched-neutral applications. Front-front terminals simplify bus-bar or cable connections in panel layouts where rear access is tight. UL/CSA listing means the breaker meets North American code requirements without additional derating or external fusing for most distribution scenarios.