SENTRON 3VA1225-4EF32-0AB0 — 250 A MCCB with TM240 Release
The Siemens SENTRON 3VA1225-4EF32-0AB0 is a 3-pole molded case circuit breaker (MCCB) rated for 250 A continuous current with a TM240 thermal-magnetic overcurrent release. It is designed for line protection in distribution panels and motor control centers. Breaking capacity scales with system voltage: 121 kA at 240 V AC, 75.6 kA at 415 V, 25 kA at 440 V, and 11.9 kA at 690 V. That SCCR headroom covers most industrial fault-current scenarios without cascading upstream breakers. Rated insulation voltage is 800 V, and the unit carries IP40 protection on the front face — suitable for enclosed panel mounting where the front is behind a door.
Current Rating Across Ambient Temperature
The 250 A rating holds flat from 40 °C to 50 °C ambient. Above that, it derates linearly: 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 hot rolling-mill panel near the furnace, that derating curve is what governs the real load it can carry — the 250 A nameplate only counts if you keep the enclosure below 50 °C.
Physical Integration and Auxiliaries
Dimensions: 105 mm wide, 158 mm high, 70 mm deep — a standard 3-pole MCCB footprint that fits existing SENTRON panel cutouts and busbar systems. It ships with 2 auxiliary switches (HP type) for status feedback to a PLC or indication lamp. No undervoltage release, no voltage trigger, no ground-fault monitoring, no communication module — this is a base-configuration breaker for straightforward line protection.