The Siemens SENTRON 3VA1332-5MH32-0AA0 is a 3-pole molded case circuit breaker rated for a continuous 320 A — and it holds that full rating from 40 °C right through 50 °C ambient, which is the real-world panel temperature for most industrial switchboards. Above that, the thermal derating is modest: 313 A at 55 °C, 306 A at 60 °C, 299 A at 65 °C, 292 A at 70 °C. That means you can load it at nameplate in a ventilated enclosure without having to oversize the frame for ambient headroom. For a protection engineer, that is a deliberate choice: the trip curve is locked at the factory, eliminating the risk of a field-adjustment error that could mis-coordinate with downstream breakers. The trade-off is that you cannot re-range it for a different cable size or motor FLA without swapping the entire breaker. Breaking capacity is where this frame earns its place in a high-fault installation: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 11.9 kA at 690 V. Those numbers cover most industrial LV distribution — 240 V single-phase taps, 400 V three-phase common in European and Asian plants, and 480/500 V North American services. Rated insulation voltage is 800 V, and the operating temperature range spans -25 °C to 70 °C, with storage from -40 °C to 80 °C.
The 3VA1332-5MH32-0AA0 measures 248 mm high, 138 mm wide, and 110 mm deep — a 3-pole frame. It mounts via screw-on lugs or a DIN-rail adapter plate; the 138 mm width fits a standard MCC bucket or panel cutout.