The Siemens SENTRON 3VA2340-5JQ32-0KH0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current of 400 A at 40 °C and an interrupting capacity of 187 kA at 240 V. That 187 kA figure at 240 V is the headline number that tells you this breaker holds the unit on the grid under a hard fault — it will clear a bolted fault without cascading upstream, provided the available fault current at the panel doesn't exceed that rating. For a 415 V or 440 V system the interrupting capacity settles to 121 kA, still substantial enough for most industrial distribution.
Interrupting capacity and thermal derating
At 500 V the interrupting capacity drops to 75.6 kA, and at 690 V it is 7.5 kA — a steep roll-off that reflects the physics of arc extinction in air at higher system voltages. The continuous current rating holds at 400 A from 40 °C through 50 °C; above that it derates linearly to 300 A at 70 °C. If the breaker lives in a hot enclosure — say a switchroom without active cooling — the 55 °C figure of 375 A is the one you size against, not the 400 A nameplate.
Physical integration and auxiliary options
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep — a standard MCCB footprint for panel mounting on a backplate or DIN rail adapter. It ships with a shunt trip (STL) for remote tripping and an auxiliary switch block configured as 2 auxiliary switches plus 1 trip alarm switch (HQ). The basic switch variant is 3VA2340-5JQ32-0AA0, which shares the same frame and trip unit. Maximum power dissipation at rated current is 96 W; account for that heat load in the enclosure thermal calculation.