What it is and what it does
The Siemens SENTRON 3VA2340-5HN32-0JC0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current, designed for line protection in distribution panels. It carries a breaking capacity of 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V — the high interrupt rating at the lower voltages means it can handle substantial fault current on 240 V or 400 V services without cascading upstream. The breaker includes a shunt trip release (STL) and two auxiliary switches HQ, so it can be remotely tripped and its status signaled back to a PLC or annunciator panel.
Thermal derating and panel fit
At 40 °C, 45 °C, and 50 °C ambient the breaker holds its full 400 A rating; at 55 °C it derates to 385 A, at 60 °C to 370 A, at 65 °C to 355 A, and at 70 °C to 340 A — useful when the breaker sits in a warm enclosure or near other heat sources. Dimensions are 248 mm high, 138 mm wide, and 110 mm deep — the 110 mm depth means it fits standard-depth MCCB compartments without a gland-plate extension. Maximum power loss is 96 W, so account for that heat in the enclosure thermal budget.
Lifecycle and sourcing
The basic switch variant is 3VA2340-5HN32-0AA0, which is the core breaker without the shunt trip and auxiliary switches; this -0JC0 suffix adds those accessories factory-installed.