What it is and what the ratings mean
The Siemens 3VA1112-6MH36-0CA0 is a 3-pole IEC frame 160 molded case circuit breaker rated 125 A with a 70 kA breaking capacity at 415 V AC — that is class H on the 3VA1 platform, meaning it can safely interrupt fault currents up to 70 kA without upstream devices needing to clear the fault first. The TM120M thermal-magnetic release provides starter protection (motor branch circuit) with an adjustable magnetic short-circuit pickup Ii = 5 to 15 × In. Note the description flags "without overload protection" — the TM120M here is configured for short-circuit protection only; the overload function is omitted, so a separate overload relay is required for motor overload protection.