The TMA2 designation means the trip curve is fixed — thermal protection for overloads, magnetic for short-circuits — with no electronic adjustment. This is a panel-mount device sized for distribution and motor branch circuits in industrial switchboards and commercial mains.
The 250 A TMA2 trip unit sets the continuous current rating — this breaker is sized for a 250 A feeder or a large motor load (typically a 132–160 kW motor depending on voltage and duty). The thermal-magnetic trip gives fixed overload protection with no field-adjustable settings; if the load profile requires a different trip curve or adjustable long-time pickup, you would need the electronic-trip variant in the same XT4S frame. The fixed curve simplifies specification but means the trip coordination study must match the TMA2 characteristic exactly.