Its interrupting capacity reaches 242 kA at 240 V AC, 187 kA at 415/440 V, and 121 kA at 500 V — figures that place it squarely in high-fault-duty applications like main feeders or large industrial switchboards. The 400 A frame is the same across the 3VA2 platform, so the breaker itself is the current-limiting element; no derating needed up to 50 °C, then it steps down to 385 A at 55 °C and 340 A at 70 °C.
At 690 V the rating drops to 7.5 kA, which is typical for a 400 A frame; if your system runs at 690 V and fault levels exceed that, you need a larger frame or a current-limiting upstream device. The 400 A continuous rating and the 3-pole construction mean this breaker coordinates with downstream 3VA2 feeders in a selective scheme, provided the upstream breaker's instantaneous trip is set above the downstream let-through.
The 138 mm width is standard for a 3-pole 400 A frame in the SENTRON 3VA2 family — it fits the same mounting footprint as other 3VA2 breakers of this rating.