Trip unit and coordination
The XT2NU3090BFF000XXX: The TMA 90-450-900 trip unit on this XT2N frame gives you an adjustable thermal-magnetic curve — the thermal pickup range (90–450 A) and the magnetic trip setting (900 A) let you dial in selectivity with downstream breakers without swapping the whole unit. At 125 A frame rating, this MCCB sits in the middle of the XT2N line — sized for branch feeders and small main service entrances where you need UL/CSA listing for North American panels.
The UL/CSA listing means this breaker is accepted in North American panels without a separate evaluation — one less headache for the panel shop.