400 A line-protection MCCB with high interrupting capacity
The Siemens SENTRON 3VA2340-6KP32-0BL0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous at 40 °C, with a trip unit adjustable between 600 A and 4 000 A. The breaking capacity reaches 242 kA at 240 V AC and 187 kA at 415 V, tapering to 7.5 kA at 690 V — this is a distribution-class breaker sized for high-fault main feeders, not motor branch circuits. The part carries an undervoltage release (UVR) and a complement of auxiliary switches: 2 auxiliary switches + 1 trip alarm switch + 1 electrical alarm switch HQ. It includes a trip indicator and a communication function, and the design intent is line protection — meaning it is optimized for cable and busbar protection in switchboards and panelboards.
Current ratings and thermal derating
The breaker holds 400 A continuously up to 50 °C ambient. Above that, derating is linear: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. The operating range spans -25 °C to +70 °C; storage limits are -40 °C to +80 °C. Maximum power loss is 98.5 W.