Part identification and fit
The XT1HU3050AAA000XXX: The description confirms this is an XT1H frame breaker fitted with a 125 A TMF (thermal-magnetic fixed) trip unit. The TMF designation means the thermal and magnetic trip elements are factory-set and non-interchangeable in the field — a fixed-characteristic breaker sized for a specific load. The XT1H frame is a compact MCCB designed for panelboard and distribution board mounting, rated for 125 A continuous at 40 °C.