What it is and what the ratings mean
The Siemens 3VA1112-6MH36-0AB0 is a 3-pole molded-case circuit breaker (MCCB) on the IEC 160 A frame, with a 125 A rated current (In) and a TM120M thermal-magnetic trip unit configured for starter protection — meaning it's sized to sit ahead of a motor starter, providing short-circuit protection while relying on the starter's overload relay for overcurrent protection. Rated Icu = 70 kA at 415 V AC, which is the maximum short-circuit current it can safely interrupt without damage at that voltage — class H breaking capacity, so it handles high prospective fault levels common in industrial distribution panels. The short-circuit release (Ii) is adjustable between 5 and 15 times In.
Deployment context
Mounts on a DIN rail or panel base inside a standard industrial enclosure; the clamp-type terminals accept copper or aluminum conductors up to the frame rating, and the two built-in auxiliary switches (HP type) provide status feedback to a PLC or indication panel without needing an external accessory block.