Siemens 3VA1332-7EE42-0AA0 SENTRON MCCB, 320 A, 4-Pole, TM22

It carries 4 poles and a TM220 thermal-magnetic trip unit, rated at 320 A continuously at 40 °C ambient — the current holds flat through 50 °C, then derates to 292 A at 70 °C, which is the maximum operating temperature. That thermal curve matters for panel builders: if your enclosure runs hot, the breaker self-limits before the load does. Breaking capacity is the headline number here: 440 kA at 240 V AC, 242 kA at 415 V, and still 154 kA at 500 V. For a 320 A frame, those are high-interrupting ratings — the kind you spec for a main feeder or a high-fault industrial service entrance where the utility transformer is close. Physical footprint: 248 mm tall, 184 mm wide, 110 mm deep. Front face carries IP40 protection — splash protection on the front cover, but the terminals themselves are not sealed. Power loss at full rated current is 80.1 W, which you need to account for in the enclosure thermal calculation.