400 A MCCB with ETU560 — what the ratings mean for fit
The Siemens 3VA2340-5JQ42-0AG0 is a SENTRON molded case circuit breaker rated 400 A continuous at 40 °C ambient, with the ETU560 electronic trip unit providing adjustable overload and short-circuit protection curves. That 400 A rating holds through 50 °C — only above 55 °C does it derate, stepping down to 375 A at 55 °C and 300 A at 70 °C, so panel builders can size this breaker into a warm enclosure without losing headroom. Breaking capacity is 187 kA at 240 V, 121 kA at 415 V and 440 V, and 75.6 kA at 500 V — figures that cover high-fault utility feeds and large motor control centers. At 690 V the rating drops to 7.5 kA, so for 690 V applications verify the available fault current stays under that threshold. The 4-pole design with ground-fault monitoring via summation current formation on L+N conductors means this unit can serve as the main disconnect for a solidly-grounded wye system where ground-fault protection is required. The auxiliary contact version includes one auxiliary switch and one trip alarm switch (HP type), providing status feedback for PLC or SCADA monitoring.
Panel integration and physical fit
The 3VA2340-5JQ42-0AG0 occupies 184 mm width, 248 mm height, and 110 mm depth on the panel. That 110 mm depth is the dimension from the mounting surface to the front cover — relevant when sizing the enclosure depth, especially if a rotary handle or motor operator is added. The 184 mm width for a 4-pole frame is standard for this class; verify the backplate cutout matches the Siemens 3VA mounting pattern if replacing an older 3WL or 3VF frame.