What this MCCB delivers
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. Designed for line protection, it includes a shunt trip (STL) and two auxiliary switches (HQ) for remote status and trip indication. 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.
Thermal derating and real-world current
The 400 A rating holds from 40 °C through 50 °C ambient. 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. That derating curve is the number to size against, not the catalog maximum.
Integration and panel fit
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.