The Siemens SENTRON 3VA2340-5JQ42-0HC0 is a 4-pole molded case circuit breaker rated for 400 A continuous current at 40 °C, with a maximum interrupting capacity of 187 kA at 240 V AC. That interrupting rating drops to 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V — so the voltage class of your distribution determines the fault-clearing headroom. The 96 W maximum power loss matters for enclosure thermal management; plan ventilation or derating if the panel runs near the 70 °C upper operating limit.
Above that, derate linearly: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. If your panel ambient sits at 55 °C, the breaker is good for 375 A continuous — not the full 400 A.
The breaker measures 248 mm high, 184 mm wide, and 110 mm deep. That 184 mm width on a 4-pole frame is standard for SENTRON 3VA2 — it occupies the same footprint as other 4-pole units in the series. The shunt trip and auxiliary switches are factory-fitted; no field assembly of those accessories. Communication function is built in, so you can integrate status and trip data into a line monitoring system without an add-on module.