What the 250 A TMF rating means for fit
The XT4HQ3200AFF000XXX: The 250 A TMF trip unit provides thermal overload protection (inverse-time) and magnetic short-circuit protection (instantaneous) at a fixed setting. For a panel builder or MRO planner, this means the switch is sized for a 250 A continuous load — typically a large motor, a bank of secondary feeders, or a main disconnect on a sub-distribution board. The TMF design eliminates field-adjustable trip dials, so the coordination curve is fixed; verify that the 250 A frame and its instantaneous pickup align with your upstream protective device's selectivity study. The XT4H frame accepts standard ABB accessories (auxiliary contacts, shunt trips, undervoltage releases, motor operators) that mount without drilling or wiring modifications.
The XT4H switch mounts on DIN-rail or base-plate inside an industrial control panel. Its footprint is typical for a 250 A molded case switch.
