400 A MCCB for line protection — what the ratings mean in the panel
The Siemens SENTRON 3VA2340-5HN32-0AD0 is a 3-pole molded case circuit breaker rated for 400 A continuous current at 40 °C, with no derating needed up to 50 °C — it holds full 400 A through that range, then steps down to 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. That thermal curve means a panel builder can size this breaker into a 50 °C enclosure without oversizing the frame. Breaking capacity is 187 kA at 240 VAC, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V. At typical 480 V industrial distribution, the 121 kA SCCR gives substantial headroom for high-fault panels — no need to cascade a current-limiting fuse upstream for most installations. Designed for line protection (not motor or generator protection), this MCCB carries the SENTRON branding and ships with three HQ auxiliary switches pre-installed. No undervoltage release, no ground-fault monitoring, no communication module — it is a straightforward thermal-magnetic or electronic-trip line breaker for main feeder or large subfeed duty. Power dissipation is 96 W maximum at rated load — relevant for enclosure thermal calculations when grouping several breakers in a switchboard section.
Physical fit and panel integration
Dimensions: 248 mm height, 138 mm width, 110 mm depth. The 138 mm width is standard for a 3-pole SENTRON 3VA frame — fits existing DIN-rail or mounting-plate layouts without re-drilling. Depth of 110 mm (4.33 in) clears most standard enclosure depths.