What this 400A MCCB carries
The Siemens 3VA2340-6JP42-0BC0 is a 4-pole IEC frame 400 molded case circuit breaker with breaking capacity class H — meaning it interrupts 85 kA at 415 V AC without damage. That SCCR headroom covers most industrial distribution panels downstream of a transformer, giving the site electrical engineer selectivity margin against a 50 kA fault on the secondary side. The ETU550 trip unit is LSI configurable: overload protection Ir adjustable from 160 A to 400 A, short-time pickup Isd from 0.6 to 10× In, and instantaneous Ii from 1.5 to 10× In. The description also notes an undervoltage release (24 V DC) accessory compatible with 3VA1 and 3VA20 frames, plus up to 2 auxiliary switches — these are field-fit, so the commissioning engineer should verify the UVR coil voltage matches the control circuit before energizing.