400 A MCCB with 242 kA interrupting capacity at 240 V
The Siemens SENTRON 3VA2340-6HM32-0AA0 is a 3-pole molded case circuit breaker rated for 400 A continuous current at 40 °C, with a maximum interrupting capacity of 242 kA at 240 V AC. The breaking capacity drops to 187 kA at 415 V and 440 V, 121 kA at 500 V, and 7.5 kA at 690 V — so the voltage at the fault point determines whether this breaker clears a high-fault event or needs upstream coordination.
Thermal derating and power dissipation
The 400 A rating holds from 40 °C through 50 °C ambient. Above that, derate linearly: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. Maximum power loss is 96 W — a figure to account for in enclosed panel heat calculations, especially if the breaker is mounted alongside other high-current devices.
Dimensions and panel fit
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep. The 138 mm width across three poles is standard for this class of SENTRON MCCB; verify the existing busbar or lug spacing matches before committing the panel layout.
Ground-fault and line protection design
The breaker is designed for line protection, with a ground-fault monitoring version that uses summation current formation on the L-conductor. Rated insulation voltage is 800 V. There is no undervoltage release, no voltage trigger, and no communication function on this variant — it is a straight thermal-magnetic or electronic-trip MCCB for distribution feeder duty.