400 A MCCB with 242 kA interrupting — selectivity headroom for high-fault panels
The Siemens SENTRON 3VA2340-6HN32-0AD0 is a 3-pole molded case circuit breaker rated for 400 A continuous at 40 °C ambient, with a full-rated interrupting capacity of 242 kA at 240 V AC and 187 kA at 415 V. That interrupting rating means it can clear a bolted fault at those levels without the arc re-striking — critical for main-breaker positions on high-capacity transformers or busway feeds where upstream coordination demands a high SCCR. The breaker carries three high-performance auxiliary switches (HQ type) for remote status feedback — useful for PLC-based load shedding or generator interlock sequences. No undervoltage release or ground-fault module is fitted on this variant; those are add-on options in the 3VA platform.
Derating curve — the real usable current depends on your panel ambient
The 400 A rating holds flat from 40 °C through 50 °C. Above that it steps down: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If your enclosure runs hot — say a solar combiner box or a non-ventilated switchroom — size the breaker one frame down or verify the actual load against the 70 °C figure. The maximum power loss is 96 W, which matters for thermal coordination inside a sealed panel.
Physical fit — panel cutout and mounting
Dimensions are 248 mm high, 138 mm wide, 110 mm deep. That depth (110 mm) is the body depth behind the panel face — important for shallow enclosures where cable bend radius competes with the breaker footprint. The 138 mm width is the standard 3-pole MCCB form factor for this SENTRON frame; it occupies three 45 mm pole spaces on a DIN rail or mounting plate.