What this MCCB is and what the ratings mean for the panel
The Siemens SENTRON 3VA2340-6JQ32-0AF0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection — the primary feeder breaker in a distribution panel, not a motor-protective device. Its electronic trip unit is adjustable from 600 A to 4000 A full-scale, with an initial setting of 80 A, meaning you dial in the exact overload threshold for the downstream load, not a fixed rating. The 242 kA interrupting capacity at 240 V tells you this breaker can safely clear a fault up to that level without welding contacts or venting plasma into the enclosure — critical for high-fault-capacity services like transformer secondaries or large busway feeds. At 415 V and 440 V it still holds 187 kA, dropping to 121 kA at 500 V and 7.5 kA at 690 V; that steep roll-off above 500 V means you verify the available fault current at the point of installation before committing the BOM line. Thermal derating is baked into the spec: the breaker carries 400 A continuously at ambient up to 50 °C, then drops to 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. If your panel ambient runs above 50 °C — common in compact, high-density switchgear — you must size the breaker for the derated current, not the nameplate 400 A. The 96 W maximum power loss at rated load matters for enclosure heat-rise calculations; that's the heat you need to vent through the gland plate or forced-air path. 248 mm tall, 138 mm wide, 110 mm deep. 3-pole form factor.
Lifecycle and sourcing posture
Quoted to order against an RFQ through independent distribution. Availability and pricing confirmed at quote time.
Integration and compliance notes
Ships with one auxiliary switch and one trip alarm switch (HQ design). No undervoltage release and no auxiliary release fitted. Communication function onboard. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The storage limit governs handling and warehousing — the breaker can sit in a cold warehouse at -40 °C without damage, but it won't operate below -25 °C. The trip indicator (a mechanical flag visible on the front cover) gives a clear visual that the breaker has tripped on fault, not just been switched off — useful for a technician walking a lineup.