What this MCCB carries — and what that means for your panel
The Siemens SENTRON 3VA2340-7HN32-0BH0 is a 3-pole molded case circuit breaker rated for 400 A continuous current at 40 °C, with a maximum breaking capacity of 330 kA at 240 V. That 330 kA figure is the interrupting rating at the lowest voltage — at 415 V it still clears 242 kA, and at 690 V it holds 7.5 kA. For a line-protection device, this means it can sit at the main service entrance or a high-fault busway where available fault current is substantial, without needing a current-limiting fuse upstream. The 400 A frame is thermally rated to carry full load continuously at 40 °C through 50 °C; above that, the continuous rating steps down to 385 A at 55 °C and 340 A at 70 °C, so a panel builder should check ambient temperature inside the enclosure before committing the BOM line. The breaker includes an undervoltage release (UVR) and a complement of auxiliary switches: two auxiliary switches plus one trip alarm switch (HQ). That switch complement is enough to signal breaker position and trip state back to a PLC or status panel without an external interposing relay. The UVR will trip the breaker if control voltage drops below its dropout threshold — a standard requirement for emergency-stop circuits and safety-related disconnect schemes where loss of control power must open the main contacts.
Physical fit and panel integration
Dimensions are 248 mm high, 138 mm wide, and 110 mm deep. That depth of 110 mm is the body depth — the breaker will fit a standard 200 mm deep enclosure with room for rear-mounted busbars or a backplate. The 138 mm width for a 3-pole frame is typical for this class; verify the mounting footprint against the existing panel cutout if you are retrofitting into a panel originally built for a different MCCB brand. Maximum power loss is 98.5 W at rated current. That loss figure drives enclosure ventilation sizing — in a sealed stainless steel enclosure at 50 °C ambient, the heat rise from this breaker alone may require forced air or a larger cabinet to stay within the 70 °C operating maximum.