The Siemens 3VA1112-6MH36-0CC0 is a 3-pole IEC frame 160 circuit breaker from the 3VA1 series, rated at 125 A with a breaking capacity class H — Icu=70kA @ 415V. This puts it squarely in the high-interrupting category for industrial panel feeders and motor branch circuits where fault currents can exceed 50 kA. The TM120M thermal-magnetic release provides starter protection (motor branch-circuit protection per IEC 60947-4-1), with an adjustable magnetic trip Ii=5...15 x In, meaning you can set instantaneous pickup between 625 A and 1875 A to coordinate with downstream contactors and overload relays.
What the ratings mean for fit
The 70 kA @ 415 V Icu is the ultimate short-circuit breaking capacity — the breaker can safely interrupt a fault up to that level once and still carry rated current afterward. For a 125 A feeder on a 415 V distribution board with transformer impedance giving a prospective fault current in that range, this breaker clears it without cascading upstream. The class H designation (70 kA) is the highest in the 3VA1 frame 160 lineup; standard class N (36 kA) and class S (50 kA) siblings exist if your SCCR study shows lower fault levels. Starter protection TM120M means the thermal element is sized for motor starting duty — it tolerates the inrush without nuisance tripping while still providing overload protection for the motor circuit. Note the description states 'without overload protection short-circuit protection' — this variant ships with the TM release configured for magnetic (short-circuit) only; the thermal overload function is present but the breaker is ordered without the overload protection function enabled, intended for use with a separate overload relay downstream. The adjustable Ii=5...15 x In gives flexibility to coordinate with the motor locked-rotor current. The undervoltage release (UVR) is rated 120-127 V AC 50/60 Hz. When voltage drops below about 70% of rated, the UVR trips the breaker open — standard for applications where a motor must not auto-restart after a power dip. Two auxiliary switches (HQ — high-qualified, meaning high-reliability contacts) provide status feedback to the PLC or annunciator panel. Clamp connection (box lug) terminals accept copper or aluminum conductors, common in North American and export panels.
Deployment context
This breaker mounts on a DIN rail or directly to a mounting plate inside a distribution panel or motor control center. The 3VA1 frame 160 is a standard panel-building component — its footprint matches Siemens's SENTRON line, so it integrates into existing busbar systems and enclosure cutouts without modification. The UVR and aux switches are factory-installed, reducing field wiring time.