The Siemens 3VA1112-5MH36-0DH0 is a 3-pole IEC frame 160 molded case circuit breaker rated 125 A with an ultimate breaking capacity Icu of 55 kA at 415 V AC. The 'M' breaking capacity class positions it for high-fault industrial distribution panels where 55 kA SCCR at 415 V is needed to safely interrupt bolted faults without cascading upstream — typical for main or large feeder breakers in heavy manufacturing or utility substations.
Starter Protection and Auxiliary Configuration
This unit ships with the TM120M thermal-magnetic release set for starter protection — the 'AM' designation means it provides short-circuit protection only (no overload protection), with an adjustable instantaneous trip Ii of 5 to 15 times In. Factory-fitted accessories include an undervoltage release (UVR) rated 208-230 V AC 50/60 Hz, two HQ auxiliary switches, and one HQ trip alarm switch. The HQ designation indicates high-auxiliary-rated contacts for control-circuit isolation. The UVR will trip the breaker on voltage drop or loss — wire it through an emergency-stop or undervoltage monitoring relay to prevent automatic restart after a line fault.
Installation Context
The 3VA1 frame breaker mounts in standard switchgear or panelboard cutouts with a DIN-rail adapter kit available for enclosure mounting. The clamp connection terminals simplify field wiring compared to lug-and-screw terminations — strip length and torque values per the manufacturer's published installation instructions. The UVR and auxiliary switches are pre-installed at the factory, reducing field labor and risk of miswiring.