The ABB XT4HU3250BYL000XXX is a NEXT4H 250 TMA 250 molded case circuit breaker, 3-pole, with a fixed thermal-magnetic trip unit rated 250 A and an adjustable overload range of 1250..2500 A. The "FF" designation indicates a fixed front terminal connection, and the "UL/C" suffix confirms UL and CSA certification for North American and Canadian installations. This is a current-production part, actively sourced through independent distribution channels.
What the ratings mean for fit
The 250 A frame size with a 1250..2500 A adjustable thermal-magnetic trip range means this breaker is sized for high-current branch circuits — think large motor control centers, feeder distribution in industrial plants, or main disconnects on heavy machinery. The TMA trip unit provides both thermal (overload) and magnetic (short-circuit) protection, with the magnetic pickup fixed at a multiple of the rated current. The 3-pole configuration handles three-phase loads up to 480 VAC (typical UL 489 rating for this frame class).
Panel integration notes
This breaker mounts on a DIN rail or directly to a backplate via the fixed terminals. The fixed front (FF) connection pattern is standard for panelboard or switchboard mounting — no plug-in base required. The 250 A frame occupies roughly 105 mm per pole width; plan for adequate side clearance for heat dissipation and cable bending radius. The UL/CSA listing means it is accepted in North American panels without additional agency review.