What this 400 A SENTRON frame carries
The Siemens SENTRON 3VA2340-6JQ32-0DH0 is a 3-pole molded case circuit breaker on a 400 A frame, designed for line protection. It ships with an undervoltage release (UVR) fitted, two auxiliary switches plus one trip alarm switch (HQ configuration), and onboard communication function — so it's ready for a panel that needs remote status and a coordinated trip signal, not just a standalone disconnect. Breaking capacity scales with system voltage: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 7.5 kA at 690 V. That 242 kA figure at 240 V tells you this breaker is sized for high-fault utility or transformer-secondaries where the available short-circuit current is extreme — not every MCCB in the 3VA family carries that headroom. Current rating holds at 400 A from 40 °C through 50 °C ambient, then derates 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, the continuous current you can pull drops — size your load against the derated figure, not the frame label. Dimensions: 248 mm high, 138 mm wide, 110 mm deep. The 138 mm width is a standard 3-pole MCCB footprint for this frame class — it fits the same DIN-rail or mounting-plate cutout as other SENTRON 3VA breakers in the 400 A range, so a panel laid out for a 3VA2225-5JQ32-0AK0 will accept this unit without re-drilling the gland plate.
What's inside the box — auxiliary and release configuration
The breaker comes with an undervoltage release (UVR) as the auxiliary release — that's the coil that drops the breaker when control voltage is lost, standard for emergency-stop or undervoltage protection schemes. Auxiliary switching is handled by two auxiliary switches plus one trip alarm switch (HQ designation), giving you three separate signal paths: two for position feedback (open/closed) and one dedicated to the tripped state. Max power loss is 98.5 W at rated load — that's the heat the breaker dumps into the enclosure. For a panel with multiple breakers ganged together, that figure drives the ventilation or derating calculation; don't bury it in a sealed box without accounting for the thermal rise. The basic switch (the bare breaker without accessories) is order code 3VA2340-6JQ32-0AA0 — useful if you're comparing a bare unit against this fully-populated variant to see what the UVR and aux switch package adds to the BOM line.
Environmental and operating range
Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The storage minimum is lower than the operating minimum, which is typical — the breaker can sit in a cold warehouse but needs to be above -25 °C before you close it on a load. The 70 °C operating max matches the top end of the derating curve, so the thermal limit is consistent.