What this breaker is and what the ratings mean
The Siemens 3VA1112-5MH36-0JH0 is a 3-pole IEC molded case circuit breaker on the 160 A frame, configured for motor starter protection without integral overloads — the TM120M release provides magnetic-only short-circuit protection with an adjustable instantaneous trip (Ii) from 5 to 15 times In. The 125 A continuous rating (In) sets the thermal current-carrying capacity; the 55 kA Icu at 415 V tells you it can safely interrupt a fault up to that level without failing, which is the Class M breaking capacity on the 3VA1 platform. That 55 kA at 415 V is the key number for panel designers sizing upstream coordination — it determines whether this breaker clears a bolted fault before the upstream device has to act.
Deployment context and integration
This breaker mounts on a DIN rail or directly to a backplate in a standard IEC distribution panel. The clamp-type terminals accept copper or aluminum conductors within the rated cross-section range. The factory-fitted shunt trip (STL) operates on 110–127 V DC or AC 50/60 Hz, letting you integrate remote tripping from a safety relay or PLC output. Two auxiliary switches (HQ) and one trip alarm switch (HQ) provide status feedback — one pair for breaker position, one for fault indication — which is enough for a motor control center (MCC) bucket or a standalone starter feeder.