What the ratings mean for your panel
The Siemens SENTRON 3VA1112-6EF32-0JA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection — it sits upstream of feeders and motor branches to clear faults before they propagate. Rated continuous current Iu is 125 A, and it holds that rating from 40 °C through 50 °C ambient; above that it derates to 120 A at 55 °C, 117.5 A at 60 °C, 115 A at 65 °C, and 112.5 A at 70 °C. For a panel builder, that means the 125 A nameplate is good in a standard 50 °C enclosure — no derate needed unless the ambient climbs higher. Breaking capacity is the headline here: 220 kA at 240 V, 154 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V. At 415 V (common in industrial three-phase systems), the 154 kA SCCR means it safely interrupts a fault that high without upstream fuses needing to clear — a real advantage in high-fault installations like substation feeders or large motor control centers. The overcurrent release is a TM240 — a thermal-magnetic fixed-trip unit set for 125 A. No communication module, no ground-fault monitoring, no phase-failure detection. This is a straightforward, no-frills line-protection MCCB. It does carry a shunt trip (STL) release for remote tripping (part number 3VA9688-0BL32 for the integrated auxiliary trip). No undervoltage release, no auxiliary contact. If you need remote status or undervoltage protection, you'll add those externally.
Mechanical fit and environment
Dimensions: 130 mm high, 76.2 mm wide, 70 mm deep. Width is a standard 3-pole MCCB footprint (roughly 3 inches) — fits most panel-mounted MCCB bases without re-drilling. Protection class IP40 on the front, meaning it's protected against tools and small wires but not washdown; suitable for indoor panel installation, not for wet or dusty environments. Operating temperature range -25 °C to 70 °C; storage from -40 °C to 80 °C.