What it is and what the ratings mean
The Siemens SENTRON 3VA2340-7HN32-0CA0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current at 40 °C, designed for line protection in distribution panels. The 330 kA interrupting rating at 240 V AC means it can safely clear a fault of that magnitude without rupturing — critical for high-fault-capacity service entrances or industrial feeders. At 415 V the rating holds at 242 kA, dropping to 187 kA at 500 V and 7.5 kA at 690 V, so the voltage class of your installation determines which breaking capacity applies. The 400 A rating holds flat through 50 °C; above that it derates to 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If your panel ambient runs above 50 °C, size the breaker for the derated figure — the nameplate 400 A is only valid up to that threshold. This variant includes an undervoltage release (UVR) as the auxiliary release, meaning the breaker trips automatically when supply voltage drops below a set threshold — used for under-voltage protection on motor circuits or to coordinate with an emergency-stop chain. It ships without auxiliary switches or ground-fault monitoring.
Panel fit and integration
Dimensions are 138 mm wide, 248 mm high, and 110 mm deep — a standard 3-pole MCCB footprint for Siemens SENTRON 3VA frames. The depth of 110 mm (4.33 in) is the projection from the mounting surface to the front of the breaker; verify gland-plate clearance if the panel has a shallow door or rear-mounted buswork. Power dissipation at rated load is 98.5 W maximum. In a sealed enclosure with multiple breakers, that heat must be factored into the thermal budget — forced ventilation or a larger cabinet may be needed to stay below the 50 °C ambient where derating begins.