What it is and what it does
The Siemens SENTRON 3VA1225-5EF42-0JA0 is a 4-pole molded case circuit breaker (MCCB) rated for line protection, with a rated continuous current Iu of 250 A and a rated insulation voltage Ui of 800 V. It carries a TM240 thermal-magnetic overcurrent release and an integrated shunt trip (STL) auxiliary release for remote tripping. The breaker is designed for panel mounting in industrial distribution and motor control centers, with an IP40 protection rating on the front face — suitable for dry indoor environments where splash or dust ingress is limited.
Breaking capacity — what the numbers mean for your fault-current study
The breaking capacity varies sharply with system voltage: 187 kA at 240 V, 121 kA at 415 V, 36 kA at 440 V, and 17 kA at 690 V. At 415 V — the most common three-phase industrial level — 121 kA is well above typical utility fault currents, so this breaker can be applied near the service entrance without upstream current-limiting fuses. The 690 V figure (17 kA) limits its use in 690 V drives or mining applications to lower-fault installations. Always verify the available fault current at the point of installation against these ratings.
Thermal derating and continuous current
The 250 A rating holds flat from 40 °C up to 50 °C ambient. Above 50 °C it derates: 243.3 A at 55 °C, 236.5 A at 60 °C, 229 A at 65 °C, and 223 A at 70 °C. In a sealed panel with multiple breakers ganged, expect the internal ambient to rise; size the breaker for the actual enclosure temperature, not the room temperature. The operating temperature range is -25 °C to +70 °C; storage range is -40 °C to +80 °C.
Panel fit and dimensions
Dimensions: 158 mm height, 140 mm width, 70 mm depth. The 140 mm width is typical for a 4-pole MCCB in this frame size.