What this breaker is and where it fits
The Siemens 3VA1112-5MH32-0AE0 is a 3-pole IEC frame 160 molded-case circuit breaker rated 125 A continuous, with a breaking capacity of 55 kA at 415 V (class M). It is configured for motor starter protection using a TM120M thermal-magnetic trip unit — note the TM prefix means thermal-magnetic, not electronic — and the adjustable short-circuit pickup Ii spans 5 to 15 times In. The unit ships with a nut keeper kit and four HQ auxiliary switches pre-installed, so it arrives ready for panel wiring without sourcing add-on blocks separately.
What the ratings mean for your panel
The 55 kA Icu at 415 V is the ultimate short-circuit breaking capacity — the breaker can safely interrupt a fault of that magnitude once and remain functional. For a panel with a transformer-fed 415 V supply and a fault current below that threshold, this breaker provides adequate SCCR headroom without cascading upstream. The TM120M trip unit is sized for motor starting duty: the thermal element tracks motor heating during start and running, while the magnetic element handles the inrush without nuisance tripping. The adjustable Ii (5–15 x In) lets you coordinate with downstream contactors and overload relays — set it toward the lower end for a tight short-circuit protection band on a known load, or toward the upper end if the motor's locked-rotor current demands it.
Deployment context
Mounts on a DIN rail or panel-mount in a standard distribution or motor control center enclosure. The four HQ auxiliary switches provide status feedback (open/closed/tripped) to a PLC or indication lamp without requiring a separate auxiliary contact block. The nut keeper kit simplifies busbar or cable lug termination — the nuts stay captive during wiring, which saves time on a panel with multiple breakers.