What this MCCB carries — and what it doesn't
The Siemens 3VA2440-5HN32-0AF0 is a SENTRON molded case circuit breaker (MCCB) rated for 400 A continuous current with an ETU350 electronic trip unit. That 400 A holds from 40 °C up to 50 °C without derating — at 55 °C it's still good for 384 A, and at 70 °C it's 360 A. The breaking capacity is 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 17 kA at 690 V. This is line protection only — no undervoltage release, no communication module, no phase failure detection, no ground fault monitoring. It ships with one auxiliary switch and one trip alarm switch (HQ type). The auxiliary release is integrated as 3VA9608-0BB11.
Selectivity and coordination — where the numbers matter
The 187 kA at 240 V is the maximum prospective short-circuit current this MCCB can safely interrupt at that voltage level. For a 400 V panel fed from a transformer with a high fault-current capacity, the 121 kA at 415 V gives you headroom for full selectivity downstream. The ETU350 release is adjustable, so you can dial in the I²t curve to coordinate with branch breakers. The 800 V rated insulation voltage (Ui) means it's suitable for 690 V systems without additional derating.
Panel fit — dimensions and integration
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep. It's a 3-pole unit designed for screw-mounting in a distribution panel or switchboard. The 110 mm depth is the dimension from the mounting surface to the front of the breaker — factor that into your gland-plate clearance and door swing. Maximum power dissipation is 63.5 W, so account for that in your thermal budget if you're packing multiple breakers in a sealed enclosure.