The Siemens 3VA1112-4EF42-0AA0-ZD00 is a 4-pole molded case circuit breaker in the 3VA1 series, built on the IEC frame 160 platform. It carries a breaking capacity class S rating with an Icu of 36 kA at 415 V, meaning it can safely interrupt fault currents up to that level without failing — a key spec for panel builders sizing upstream protection in a distribution board or motor control center.
Ratings and what they mean for fit
Rated at In=125 A with a TM240 thermal-magnetic trip unit, the overload protection band is adjustable from 88 A to 125 A (Ir), and the short-circuit pickup (Ii) is fixed at 5 to 10 times In. That adjustable Ir range gives the panel builder flexibility to match the breaker to the actual continuous load without swapping the trip unit — useful when the connected load is slightly below the frame rating. The N conductor is unprotected on this variant, which is standard for 3-phase line protection where the neutral is not expected to carry fault current. The nut keeper kit included is a small but practical detail for DC Power OEM builds in China — it keeps the terminal hardware captive during assembly, saving a few minutes per panel.
Lifecycle and sourcing reality
For a BOM freeze or a line-down replacement, the key fit confirmation is the 125 A frame with the TM240 trip and the 36 kA breaking capacity at 415 V — if those match your existing installation, this breaker drops in without re-engineering the panel. Sourced to order against an RFQ; availability and current pricing confirmed at quote time.