What this 400 A MCCB carries
The Siemens 3VA2440-6HN32-0CA0 is a SENTRON molded case circuit breaker rated for 400 A continuous current (Iu) with a line protection trip unit — the ETU350 electronic overcurrent release. That 400 A holds flat from 40 °C up to 50 °C; above that it derates to 384 A at 55 °C, 376 A at 60 °C, 368 A at 65 °C, and 360 A at 70 °C. For a panel builder, that means the breaker can sit in a warm enclosure without losing headroom until the ambient passes 50 °C. Breaking capacity runs 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 40 kA at 690 V. That's enough SCCR headroom for most industrial main feeders without cascading upstream — the 242 kA at 240 V covers high-fault utility drops.
Dimensions and panel fit
The 3VA2440-6HN32-0CA0 measures 248 mm high by 138 mm wide by 110 mm deep. That 110 mm depth is the dimension that matters when you're clearing the gland plate or a rear-mounted bus — it's shallower than many older MCCB frames, so it fits retrofit panels without re-drilling the backplane.
What the ETU350 release does
The ETU350 is an electronic trip unit with adjustable long-time, short-time, instantaneous, and ground-fault protection curves — though this specific variant ships without ground-fault monitoring. No communication function, no phase-failure detection, no voltage trigger. The trip indicator is also absent, so fault isolation relies on the breaker position or a separate auxiliary contact (not included).