Breaking capacity reaches 187 kA at 240 V, 121 kA at 415 V, and 75.6 kA at 440 V, which covers most industrial secondary-distribution fault levels without cascading upstream.
Thermal derating and continuous current
The 125 A rating holds flat from 40 °C up to 50 °C, then gradually declines: 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C.
This MCCB's interrupting rating varies significantly with system voltage. At 415 V the rating is 121 kA, at 440 V it is 75.6 kA, and at 500 V or 690 V it drops to 17 kA.
Physical fit and auxiliary switching
Dimensions are 130 mm high, 76.2 mm wide, and 70 mm deep — a standard 3-pole MCCB footprint that fits Siemens SENTRON mounting bases and panel cutouts. No undervoltage release, no ground-fault module, and no communication function are included on this variant — those are separate add-on accessories.