Siemens SENTRON 3VA1225-4EF42-0AG0 — 250 A MCCB, 4-Pole, TM240 Release
The Siemens 3VA1225-4EF42-0AG0 is a SENTRON molded case circuit breaker (MCCB) configured for line protection, carrying a rated continuous current Iu of 250 A across four poles. The TM240 thermal-magnetic release handles overload and short-circuit protection without undervoltage or shunt trip accessories — the auxiliary contact version ships as one auxiliary switch plus one trip alarm switch (HP type). Breaking capacity varies with system voltage: 121 kA at 240 V, 75.6 kA at 415 V, 25 kA at 440 V, and 11.9 kA at 690 V. That 121 kA figure at 240 V is the headline — it clears high-fault conditions on the secondary side of a step-down transformer or in a low-voltage distribution board without upstream coordination headaches. Thermal derating is published per the spec table: the breaker holds 250 A from 40 °C through 50 °C, then steps down to 243.3 A at 55 °C, 236.5 A at 60 °C, 229 A at 65 °C, and 223 A at 70 °C. If the panel ambient runs above 50 °C, the continuous load must be trimmed to the derated value — the datasheet curve governs, not the nameplate.
Sourcing & Lifecycle — Active Production, Quoted to Order
The operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Front-face protection is IP40, which keeps tools and fingers out but does not seal against moisture — the breaker belongs in a closed panel, not a washdown zone.