What the interrupting ratings mean for your panel
The Siemens SENTRON 3VA1150-3EF32-0JC0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, with a rated continuous current Iu of 50 A and a rated insulation voltage Ui of 800 V. Its interrupting capacity scales with system voltage: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V — so at 415 V it handles bolted faults up to 52.5 kA without upstream fuses, which is the number that decides whether this breaker clears a fault before the transformer secondary trips.
Thermal derating curve — the real current rating at your cabinet temperature
The TM240 thermal-magnetic release holds 50 A continuously from 40 °C through 50 °C ambient. Above that it derates: 48 A at 55 °C, 47 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. If your panel ambient runs at 55 °C, the breaker's effective continuous current is 48 A — not the nameplate 50 A. The operating temperature range is -25 °C to 70 °C.
Integration and auxiliaries
The breaker ships with a factory-fitted shunt trip (STL) auxiliary release and 2 auxiliary switches (HQ). The integrated auxiliary trip order code is 3VA9688-0BL32. Front protection is IP40 — suitable for a closed panel, not for washdown. Dimensions: 130 mm height, 76.2 mm width (standard 3-pole MCCB footprint), 70 mm depth. Storage range -40 °C to 80 °C.