The Siemens SENTRON 3VA2340-5JQ42-0BH0 is a 4-pole molded case circuit breaker rated for line protection, carrying 400 A continuously at 40-50 °C. That 400 A rating holds flat across the first 10 °C of ambient rise — at 55 °C it still delivers 375 A, and at 70 °C it's good for 300 A. For a panel builder, that means you don't have to oversize the frame for a warm cabinet if you're under 50 °C. The interrupting capacity is 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 17 kA at 690 V — a wide voltage range that covers most low-voltage distribution in one frame.
What the ratings mean for fit
The 400 A continuous rating is the load-side limit; the 187 kA interrupting capacity at 240 V is what the breaker can safely clear under fault. That 187 kA figure at 240 V is high — this breaker handles a stiff utility feed or a transformer secondary with very low impedance. At 690 V the interrupting capacity drops to 17 kA, which is still enough for most 690 V motor circuits but worth verifying against the available fault current at the point of installation. The ETU560 electronic trip unit gives adjustable long-time, short-time, instantaneous, and ground-fault protection curves — not a fixed thermal-magnetic, so you can dial it in for cable protection or motor branch without changing the breaker. The auxiliary contact configuration is 2 auxiliary switches plus 1 trip alarm switch (HQ type), which gives three separate status signals — one for breaker open/closed, one for a second position indication, and one dedicated to trip events. That third contact is useful for a remote alarm or a PLC input that only fires on a fault, not on a manual open. The undervoltage release (UVR) is built in, so the breaker drops out if control voltage falls below the dropout threshold — standard for applications where you need undervoltage protection on the load.
Panel integration and dimensions
The breaker measures 184 mm wide, 248 mm tall, and 110 mm deep — a 4-pole frame that fits standard MCCB panel cutouts. The 110 mm depth is the projection from the mounting surface; if you're swapping into an existing panel, check that the enclosure depth clears the rear arc chamber and wiring space. The 98.5 W maximum power loss at full load means the breaker dissipates heat into the cabinet — for a panel with multiple breakers at 400 A, that heat load adds up and needs ventilation or derating consideration. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C. The communication function allows remote monitoring and trip data.