The TM240 thermal-magnetic trip unit means the thermal element is fixed at 100 A (the frame rating), while the magnetic pickup is set at 240 A ±20 %, so it handles motor inrush without nuisance tripping on a 30–40 A motor start but clears a bolted fault fast. At 240 V the interrupting rating hits 187 kA — that is the SCCR the breaker can safely clear without venting or welding contacts, which sets the available fault current the upstream transformer or bus must not exceed. At 415 V it still holds 121 kA; at 690 V it drops to 17 kA, so verify the line-to-line voltage on a 480 V or 600 V system before specifying.
Thermal derating and deployment context
This MCCB holds its full 100 A rating up to 50 °C ambient, then begins a gentle derating curve: 98 A at 55 °C, 96 A at 60 °C, 94 A at 65 °C, and 91 A at 70 °C. That means in a ventilated 40 °C panel it works at nameplate; in a sealed enclosure near a drive or transformer, the actual load must be trimmed by up to 9 % to avoid nuisance thermal tripping over the equipment's service life.
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep — a 3-pole MCCB footprint that fits standard Siemens SENTRON panel cutouts and busbar systems.