The ABB XT1HU3090AFD000XXX is a 3-pole molded case circuit breaker from the XT1H series, fitted with a TMF (thermal-magnetic fixed) trip unit rated 90-900 A. It carries UL and CSA certifications, making it a direct fit for North American panel builds where those listings are required by code or spec.
The TMF trip unit covers a 90-900 A adjustable range, which means this breaker can be set to protect a wide band of load sizes — from a 90 A feeder to a 900 A main — without swapping the frame. The 125 A frame designation (XT1H 125) indicates the continuous current rating of the base unit; the TMF 90-900 trip block then sets the actual protection threshold.