At 240 V it's rated 187 kA, at 500 V it drops to 30 kA, and at 690 V it's 4.5 kA — so the voltage you're running governs how much fault current this breaker can handle.
Thermal derating and enclosure fit
The 160 A rating holds flat from 40 °C to 50 °C, then derates to 156 A at 55 °C, 151 A at 60 °C, 147 A at 65 °C, and 142 A at 70 °C. The dimensions are 105 mm wide, 158 mm tall, and 70 mm deep — that's 4.13 by 6.22 by 2.76 inches. The max power loss is 33 W — that's heat you have to account for in your enclosure thermal budget, especially if you're ganging several breakers side by side.
What it connects to and how it's built
This breaker is designed as a starter protection device — it's meant to be paired with a contactor and overload relay to form a motor starter combination. The TM120M release is a thermal-magnetic type: the thermal element tracks the motor's heating curve, and the magnetic element trips instantaneously on short-circuit. The rated insulation voltage is 800 V, and it operates from -25 °C to 70 °C ambient, with storage from -40 °C to 80 °C. The basic switch inside is 3VA12165MH320AA0.