What the ratings mean for fit
The Siemens SENTRON 3VA2340-6HN32-0BL0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous at 40 °C, with a maximum breaking capacity of 242 kA at 240 V AC. That 242 kA figure at 240 V tells you this breaker is sized for high-fault-current panels — typically a main or large feeder in an industrial distribution board where the available fault current is well above what a standard 65 kA or 100 kA MCCB can interrupt. At 415 V it still holds 187 kA, and at 690 V it drops to 7.5 kA, which is the voltage limit for this frame size. The 400 A continuous rating holds flat from 40 °C through 50 °C, then derates to 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C — so if your panel ambient runs above 50 °C, you need to account for that thermal curve when sizing the load. This is a line-protection design, meaning it's configured for cable and busbar protection rather than motor or generator protection. It ships with an undervoltage release (UVR) and a complement of auxiliary switches: 2 auxiliary switches + 1 trip alarm switch + 1 electrical alarm switch HQ. That switch complement gives you status feedback for the breaker position and trip condition — useful for a BMS or PLC input without adding external relays.
Panel integration and mounting
Physical footprint: 248 mm height, 138 mm width, 110 mm depth. That 110 mm depth is the overall body depth — it fits standard MCCB mounting plates and enclosure backpanels without needing a deep gland plate. The 138 mm width for a 3-pole frame is typical for this class; verify the busbar spacing and phase-to-phase clearance in your existing panel before committing the cutout.
Operating environment
Rated for operation from -25 °C to 70 °C ambient, with storage from -40 °C to 80 °C. Maximum power loss is 98.5 W — that's the heat the breaker dissipates at full rated current. In a sealed or poorly ventilated enclosure, that 98.5 W adds to the internal temperature rise, so factor it into your thermal budget.