Line protection MCCB for 125 A feeder circuits
The 125 A rating holds at 45 °C and 50 °C, then derates to 114 A at 70 °C, so the thermal curve matters if the breaker sits in a warm enclosure or next to other heat sources. Breaking capacity runs 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 500 V and 690 V. At 415 V, that 75.6 kA gives solid headroom for most industrial secondary distribution — you can coordinate downstream without worrying about the main tripping on a bolted fault. The TM210 release has an adjustable li (instantaneous trip) up to 1250 A, and the N-conductor protection is set at 50 % of the phase rating.
Panel fit and thermal management
Footprint is 101.6 mm wide by 130 mm tall by 70 mm deep — a 4-pole MCCB that fits standard Siemens SENTRON mounting. Maximum power dissipation is 28.1 W at full load; that heat has to leave the enclosure, so factor it into the cabinet thermal budget, especially when grouping several breakers.