What this MCCB carries — and what that means for your panel
The Siemens 3VA1112-4EF36-0JA0 is a 3-pole SENTRON molded case circuit breaker rated for 125 A continuous current (Iu) with a TM240 thermal-magnetic release. The 125 A rating holds flat from 40 °C to 50 °C, then 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 — so if your panel ambient runs hot, you lose about 10 % of the headline number by the time you hit 70 °C. That derating curve is the spec that decides whether this breaker holds a full 125 A feeder or needs to be upsized for a warm enclosure. Interrupting capacity is 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V. At 415 V — common in European industrial distribution — the 75.6 kA rating comfortably handles high-fault scenarios like transformer secondaries or large motor centers without needing a current-limiting upstream device.
Panel fit and integration
Dimensions: 70 mm depth, 76.2 mm width, 130 mm height. The 76.2 mm width fits Siemens SENTRON mounting plates and most DIN-rail adapters. Front protection is IP40 — sealed against tools and small wires, but not against washdown. Keep this behind a panel door in any wet or dusty environment.
Release and accessories — what's on board, what's not
The TM240 overcurrent release is a thermal-magnetic type — fixed thermal curve for overload, magnetic pickup for short-circuit. No electronic adjustment, no communication module, no phase-failure detection. The auxiliary release is a shunt trip (STL) — the integrated auxiliary trip order code is 3VA9688-0BL32, so if you need remote tripping capability, that's the add-on part number to specify alongside this breaker. No auxiliary contact version is included (without). No undervoltage release. No ground-fault monitoring. If your application demands any of those, you'll need a different variant or an external module.