It carries a continuous current of 125 A at 40 °C, and the thermal-magnetic release (TM240) handles overloads and short-circuits without an external trip unit. The interrupting capacity tells you where it can safely clear a fault: 121 kA at 240 VAC, 75.6 kA at 415 VAC, 52.5 kA at 440 VAC, and 11.9 kA at both 500 VAC and 690 VAC. The rated insulation voltage of 800 V gives headroom for 690 VAC systems, so it fits European 400 V and North American 480 V designs on the same frame.
Fit and footprint for panel integration
Dimensions are 130 mm height, 76.2 mm width, 70 mm depth. The 76.2 mm width is a standard 3-pole MCCB footprint. Depth of 70 mm leaves clearance behind the panel door for wiring space and auxiliary wiring. Maximum power loss is 28.1 W.
The 125 A rating holds flat from 40 °C to 50 °C. Above that it derates: 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, 114 A at 70 °C. The operating ambient range is -25 °C to +70 °C, storage from -40 °C to +80 °C. If the breaker sits in a hot switchroom or near a furnace line, use the 70 °C figure (114 A) for sizing — not the catalog 125 A. The TM240 release is calibrated for the thermal curve; the derating is already baked into the frame design, so you don't need to manually adjust the trip setting.