It is rated 160 A at 50 °C, with 4 poles configured as 3D (three protected poles, neutral left position with no protection). The LI protection curve covers overload (thermal, adjustable Ir from 0.7 to 1 x In) and short-circuit (magnetic, fixed Ii at 1250 A). This is the drop-in trip unit that defines the breaker's protection settings — you swap it into the NSX250 frame, not the whole breaker.
If your panel runs hotter, you derate — the TM-D's thermal element responds to both load current and ambient temperature. The fixed instantaneous trip at 1250 A (about 7.8 x In) means it clears bolted faults fast, but you lose the ability to dial up the magnetic pickup for high-inrush loads like large motors. The adjustable long-time pickup (Ir) lets you fine-tune the overload threshold between 112 A and 160 A, which is useful when the connected load is smaller than the frame rating.
Where it fits and how it mounts
This trip unit mounts into the ComPacT NSX250 fixed breaker. The breaker itself is DIN-rail or screw-panel mount, depending on the base.
Electrical shock protection class II — double-insulated, no earth connection needed.