400 A MCCB, 187 kA interrupt — this one's built for high-fault mains
Siemens SENTRON 3VA2340-5HN32-0DC0 is a 3-pole molded case circuit breaker rated 400 A continuous (Iu) with a 187 kA interrupting capacity at 240 V AC. That breaking figure drops to 121 kA at 415/440 V, 75.6 kA at 500 V, and 17 kA at 690 V — so it's sized for the main incomer where fault currents are brutal, not a downstream feeder. Holds full 400 A from 40 °C through 50 °C ambient. Derating starts at 55 °C (385 A), then 370 A at 60 °C, 355 A at 65 °C, 340 A at 70 °C. That's a shallow curve — the breaker keeps 85 % of rating at the top end, so it's not forcing a upsized frame for a hot panel. Electronic trip unit is the ETU350 — line protection version. No voltage trigger, no phase failure detection, no communication module. Undervoltage release (UVR) is fitted as the auxiliary release, plus 2 HQ auxiliary switches. The basic switch assembly is order code 3VA2340-5HN32-0AA0; the integrated auxiliary trip is 3VA9608-0BB25.
Mounting dimensions and panel fit
Maximum power dissipation at rated load is 98.5 W. That's per breaker — factor into panel thermal budget. Operating temp range -25 °C to +70 °C; storage from -40 °C to +80 °C. Rated insulation voltage Ui is 800 V. Latching endurance is 15 000 operations — not a daily-switching device; it's a protection device that stays closed.