Siemens SENTRON 3VA1225-5EF42-0HA0 — 250 A MCCB for Line Protection
The Siemens SENTRON 3VA1225-5EF42-0HA0 is a 4-pole molded case circuit breaker (MCCB) rated for 250 A continuous current (Iu) and configured for line protection. It carries a TM240 thermal-magnetic overcurrent release and a shunt trip (STL) auxiliary release, with no undervoltage release, no auxiliary contacts, and no communication function. The interrupting capacity varies by voltage: 187 kA at 240 V, 121 kA at 415 V, 36 kA at 440 V, and 17 kA at 690 V — so at typical 400 V class distribution voltages it clears faults well above the available short-circuit current in most industrial panels. The rated insulation voltage is 800 V, and front protection is IP40.
Thermal Derating and Ambient Temperature
The 250 A continuous rating holds from 40 °C through 50 °C. Above that the current must be derated: 243.3 A at 55 °C, 236.5 A at 60 °C, 229 A at 65 °C, and 223 A at 70 °C. The operating ambient range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. If the panel ambient runs hot — near a transformer or drive bank — the 55 °C derating figure is the one to size against.
Dimensions and Panel Fit
The breaker measures 140 mm wide, 158 mm high, and 70 mm deep. The 4-pole width is the critical dimension for panel layout — it occupies roughly the same footprint as other SENTRON 4-pole frames in the 250 A class. The IP40 front protection means it is suitable for enclosed distribution boards; no washdown rating.