What this 400 A MCCB delivers — and where the ratings matter
The Siemens SENTRON 3VA2340-5HL42-0DF0 is a 4-pole molded case circuit breaker rated for 400 A continuous at 40 °C, designed for line protection in distribution panels. Its interrupting capacity reaches 187 kA at 240 VAC and 121 kA at 415/440 VAC, tapering to 7.5 kA at 690 VAC — so the voltage class of your installation determines which fault level this breaker can clear without upstream coordination. Thermal derating is published across the full operating range: the breaker holds 400 A from 40 °C through 50 °C, then drops 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, the continuous current you can count on is the derated value, not the nameplate 400 A. This unit includes an undervoltage release (UVR) and a factory-fitted auxiliary switch plus trip alarm switch (1 aux + 1 alarm, HQ design). The UVR trips the breaker when control voltage drops below a threshold — common in safety circuits or generator-transfer schemes where loss of control power should open the main feeder.
Panel fit and integration
Dimensions are 248 mm high, 184 mm wide, 110 mm deep — a standard 4-pole MCCB footprint for 400 A frame size. Mounts on a DIN rail or direct panel; the 110 mm depth leaves clearance for rear-connection busbars in a typical 600 mm deep enclosure. Operating temperature range is -25 °C to +70 °C; storage range is -40 °C to +80 °C. Maximum power loss at rated load is 98.5 W — factor that into enclosure ventilation if the panel is densely packed.