The Siemens 3VA1340-5EE42-0AA0 is a 4-pole SENTRON molded case circuit breaker (MCCB) rated for 400 A continuous at 40 °C, holding that rating flat through 50 °C before a gentle thermal derating curve begins — 392 A at 55 °C, 384 A at 60 °C, down to 367 A at 70 °C. That means in a 40 °C panel environment it carries the full 400 A without headroom games; if your enclosure runs hotter, the breaker self-protects by reducing its continuous rating, so the load side must be sized for the derated value. Interrupting capacity is voltage-dependent: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, 11.9 kA at 690 V.
Lifecycle and sourcing — active, quoted to order
Panel integration — dimensions and mounting
The breaker measures 248 mm high, 184 mm wide, 110 mm deep. Four-pole frame, so it occupies the full width of the 3VA 400 A platform — no reduced neutral pole. Power loss at full rated current is 92.1 W maximum. That's the heat the breaker dissipates into the enclosure — factor it into your panel thermal calculation, especially if the MCCB is mounted alongside other high-current devices.