Ratings and fit for the panel
The Siemens 3VM1112-3GD42-0AA0 is a 4-pole molded case circuit breaker in the 3VM1 IEC frame 160 family, rated 125 A continuous with a 25 kA interrupting capacity at 415 V AC (breaking capacity class N). The TM210 thermal-magnetic trip unit provides fixed overload protection at Ir = 125 A (not adjustable) and a short-circuit pickup fixed at Ii = 10 × In, or 1250 A. For a line-protection application, that means nuisance tripping is unlikely on motor inrush or transformer energization, but the fixed overload setting locks you into a 125 A cable/conductor size — no field tweaking the long-time pickup. The 4-pole construction with full neutral protection makes it a direct fit for 3-phase + N systems where the neutral must be switched and protected — common in North American 120/208 V and 277/480 V derived systems, though the 415 V interrupting rating is IEC-grounded.
Integration and compliance notes
Packaged as a single piece in a 150 × 119 × 116 mm box. Group code P360 and product group 5377 are Siemens internal classification codes used for ordering system routing and catalog filtering, not functional specs.