What it is and what the ratings mean
The Siemens SENTRON 3VA2440-6HN32-0AB0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current at 40 °C, with an ETU350 electronic trip unit for line protection. The 400 A rating holds steady through 50 °C — only above that does it begin to derate, reaching 360 A at 70 °C. That means in a warm panel you still get full 400 A headroom up to 50 °C, which covers most industrial enclosures without oversizing. Breaking capacity is substantial: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 40 kA at 690 V. These are the interrupting ratings at the respective voltages — critical for verifying selectivity and SCCR compliance in a distribution panel. The 187 kA at 415 V is what most European industrial networks will see; it means this breaker can clear a bolted fault on a 400 V bus without upstream coordination issues. Rated insulation voltage is 800 V, and the front face carries IP40 protection — suitable for dry indoor panel mounting. The unit ships with 2 auxiliary switches (HP version) for remote status indication. No undervoltage release, no ground-fault monitoring, no communication module — this is a straight line-protection breaker, not a multifunction power monitor.
Mounting and integration
Dimensions: 138 mm wide, 248 mm high, 110 mm deep. The 138 mm width is the standard 3-pole MCCB footprint for this current class — it fits the same cutout as other 400 A SENTRON frames. Panel builders should verify the 110 mm depth against gland-plate clearance and busbar reach, but it is a common dimension for this rating. Mechanical endurance is rated at 15 000 operations — typical for a 400 A MCCB used in distribution, not for frequent switching duty. Max power loss is 63.5 W, which matters for thermal management inside a sealed enclosure.