320 A MCCB with 154 kA breaking capacity — what that means on the line
That 320 A holds all the way up to 50 °C ambient; at 55 °C it derates to 313 A, and at 70 °C it's still good for 292 A.
Where this MCCB fits in the panel
The 3-pole layout and the TM120M release mean it's set up for motor branch circuits or feeder protection where you need a fixed thermal curve and magnetic short-circuit pickup. The auxiliary switch design carries two HQ form-C contacts — handy for a remote trip-indication circuit without adding a separate accessory.
The interrupting rating drops as voltage climbs: 220 kA at 240 V, 154 kA at both 415 V and 440 V, 121 kA at 500 V, and 17 kA at 690 V.