What this MCCB delivers — and what the ratings actually mean for your panel
The Siemens 3VA2340-5HN32-0BC0 is a SENTRON molded case circuit breaker rated for 400 A continuous current (Iu) across a 3-pole frame, carrying an ETU350 electronic trip unit. The 400 A rating holds at 40 °C, 45 °C, and 50 °C; above that it derates linearly — 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 hot, the real continuous capacity is lower than the nameplate number. Breaking capacity is what decides whether this breaker clears a fault without upstream devices having to intervene. At 240 V it interrupts 187 kA; at 415 V and 440 V it delivers 121 kA; at 500 V it drops to 75.6 kA; at 690 V it still holds 17 kA. That is a high-interrupting-capacity (HIC) frame — suitable for main or tie positions in switchboards where fault current is high, not just a downstream feeder. The ETU350 trip unit is a basic electronic release — no communication, no voltage trigger, no ground-fault monitoring. It ships with an undervoltage release (UVR) and two HQ auxiliary switches. The auxiliary trip module inside is order code 3VA9608-0BB11; the basic switch assembly is 3VA2340-5HN32-0AA0. If you need phase-failure detection or a communication module, this variant does not carry them — you would move to a 3VA2 with a different suffix.
Panel integration — what fits where
Dimensions: 110 mm deep, 138 mm wide, 248 mm tall. That is a standard 3-pole MCCB footprint for the 400 A SENTRON frame — it mounts on a DIN rail or directly to a mounting plate with the screw kit. The 98.5 W maximum power loss at rated current means ventilation slots or a thermal management check in a sealed enclosure; do not bury it in a dead-air compartment. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The storage limit is what governs handling and warehousing — the operating limit is what matters for the panel environment.