400 A MCCB for line protection — what the ratings mean for fit
The Siemens 3VA2340-7HL32-0AG0 is a SENTRON molded case circuit breaker rated for 400 A continuous at 40 °C, with a 3-pole design configured for line protection. That 400 A holds flat through 50 °C — only above 55 °C does the thermal derating curve start to bite, dropping 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 hot, the 55 °C derating point is where you verify the load still fits. The interrupting ratings tell you where this breaker can sit in the fault-current hierarchy: 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 7.5 kA at 690 V. For a 400 A frame, those are high-interrupting-capacity figures — the 242 kA at 415 V means it can be applied upstream in a high-fault installation without needing a current-limiting fuse ahead of it, as long as the available fault current stays under that threshold. It ships with one auxiliary switch and one trip alarm switch (HP type) factory-fitted — no separate auxiliary release to order. The trip indicator is present, undervoltage release is not, and there is no ground-fault monitoring or communication function on this variant. The basic switch it builds on is order code 3VA2340-7HL32-0AA0.
Panel fit — dimensions and integration
At 110 mm deep, 138 mm wide, and 248 mm tall, this MCCB fits the standard SENTRON 3VA mounting footprint. The 138 mm width across three poles is the dimension to check against your existing busbar spacing or DIN-rail adapter. Depth of 110 mm leaves clearance for rear-connected busbars in a typical distribution panel. Operating temperature range is -25 °C to 70 °C, with storage from -40 °C to 80 °C. Maximum power loss is 96 W at rated current — account for that heat in your enclosure ventilation calculation, especially if the breaker is enclosed in a low-volume panel with other heat sources.