What this 3VA2 MCCB brings to a 400 A feeder
The Siemens 3VA2440-8HN32-0AA0 is a SENTRON molded case circuit breaker sized for line protection on a 400 A continuous feeder. The ETU350 electronic trip unit gives you adjustable long-time, short-time, and instantaneous protection curves — not a fixed thermal-magnetic shelf. That matters when you need selectivity downstream or want to dial in coordination with a transformer inrush or motor starting profile. Rated current holds flat at 400 A from 40 °C all the way up to 70 °C ambient (–). No derating curve to chase inside a hot panel. The interrupting capacity runs 440 kA at 240 V, 330 kA at 415/440 V, 220 kA at 500 V, and 52.5 kA at 690 V (–) — that's serious fault-clearing headroom for a 400 A frame, especially on a 480 V or 600 V class distribution board where SCCR requirements climb. Three-pole construction, no undervoltage release, no ground-fault monitoring, no communication module. This is a straight feeder breaker — no frills, no auxiliary electronics to fail. The 63.5 W maximum power loss is the heat you need to vent; factor it into the enclosure sizing if the panel is tight.
Panel fit and footprint
The 3VA2440-8HN32-0AA0 measures 248 mm tall, 138 mm wide, and 110 mm deep. That 138 mm width is the standard 3-pole MCCB footprint for this frame size — it lands on the DIN rail or mounting plate without surprises. The 110 mm depth includes the arc chamber and terminals; make sure the gland plate or rear panel clearance leaves room for incoming cable bending radius. Operating temperature range is -25 °C to 70 °C. Storage range goes from -40 °C to 80 °C. If this breaker sits in an unheated warehouse before install, that storage spec covers it. No condensation allowed during operation — standard MCCB practice.