400 A MCCB with ETU320 — what the ratings mean for fit
The Siemens SENTRON 3VA2440-6HL42-0AA0 is a 4-pole molded case circuit breaker rated for 400 A continuous current across the full 40 °C to 70 °C ambient range — no derating needed as the panel warms up. That 400 A holds steady at every temperature step from 40 °C through 70 °C, so it handles a warm enclosure without a current haircut. The ETU320 electronic trip unit gives you an adjustable trip range from 600 A to 4 800 A, which covers motor feeders, transformer secondaries, and main distribution buswork. The interrupting ratings climb to 242 kA at 240 V and hold at 187 kA through 440 V; at 690 V it still clears 9 kA. That 242 kA at 240 V means it can sit ahead of a high-fault panel without needing a current-limiting fuse upstream. Rated insulation voltage is 800 V, so it's suitable for 480 V and 600 V class systems with headroom. Max power loss is 63.5 W — factor that into your enclosure ventilation if you're packing multiple breakers in a row.
Panel fit — dimensions and mounting
The 3VA2440-6HL42-0AA0 measures 248 mm high by 184 mm wide by 110 mm deep. That 184 mm width on a 4-pole frame is typical for the SENTRON 3VA platform — it lands on the same mounting footprint as other 3VA breakers in this frame size, so a panel laid out for a 3VA2225-5HN42-0BB0 or 3VA2116-5HL32-0AK0 will accept this 400 A unit without re-drilling the backplate. The 110 mm depth leaves room for rear-connected busbars or a standard DIN-rail adapter plate.