What this MCCB carries
The Siemens SENTRON 3VA2440-7HL32-0JA0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current, with an ETU320 electronic trip unit configured for line protection. It delivers a breaking capacity of 330 kA at 240 V AC, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 52.5 kA at 690 V — figures that tell you it handles high-fault utility feeds and large transformer secondaries without cascading upstream. The shunt trip (STL) auxiliary release is integrated as standard — part number 3VA9688-0BL32 — so this breaker can be tripped remotely by a control signal, which is typical for emergency-stop circuits or supervisory shutdown in a panel. Rated insulation voltage is 800 V, and the maximum power loss at rated current is 63.5 W — a figure worth noting for enclosure thermal management when the breaker is enclosed in a non-ventilated panel.
Thermal derating and ambient limits
The 400 A rating holds flat from 40 °C through 50 °C ambient. Above that, it derates: 384 A at 55 °C, 376 A at 60 °C, 368 A at 65 °C, and 360 A at 70 °C. Operating ambient range is -25 °C to +70 °C; storage range is -40 °C to +80 °C. If your panel ambient runs hot — say, next to a furnace line or in a poorly ventilated enclosure — the 55 °C derate to 384 A is the number to size against, not the nameplate 400 A.
Panel fit and dimensions
Dimensions are 248 mm high, 138 mm wide, 110 mm deep. The 138 mm width is the standard 3-pole MCCB footprint for this current class — it occupies three 45 mm-wide pole spaces on a DIN rail or bolted to a mounting plate. No auxiliary contacts are fitted from the factory, so if you need status feedback, plan for a separate auxiliary switch block.