SENTRON 3VA1225-5EF42-0BC0 — 250 A MCCB with Undervoltage Release
The Siemens SENTRON 3VA1225-5EF42-0BC0 is a 4-pole molded case circuit breaker rated for 250 A continuous at 40 °C ambient, designed for line protection in distribution panels. Its interrupting capacity reaches 187 kA at 240 V AC, tapering to 121 kA at 415 V and 75.6 kA at 440 V — figures that govern the available fault current the breaker can safely clear without upstream coordination failure. This breaker ships with an integrated undervoltage release (UVR) and two HQ auxiliary switches, so it drops the load on loss of control voltage and reports position back to the PLC or status panel without an add-on module.
Current Rating and Thermal Derating
The 250 A rating holds flat from 40 °C through 50 °C, then derates to 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. If the panel ambient runs above 50 °C, the continuous load must be trimmed accordingly — a detail often missed when sizing for a tightly packed enclosure.
Breaking Capacity by Voltage Level
The 187 kA at 240 V is the headline number, but the real-world coordination study uses the voltage at the point of common coupling. At 415 V the breaker still clears 121 kA; at 500 V it drops to 30 kA, and at 690 V to 17 kA. Verify the available fault current at your system voltage — the 240 V figure alone can overstate the margin on a 480 V or 600 V service.
Physical Fit and Panel Integration
The breaker measures 158 mm high, 140 mm wide, and 70 mm deep — a 4-pole frame that occupies roughly the same footprint as earlier SENTRON 3VA1 generations, so a panel laid out for a 3VA1110 or 3VA1112 will accept this unit without drilling new mounting holes or reworking the bus bars. Rated insulation voltage is 800 V, and the maximum power loss at full load is 59.5 W — a figure to include in the enclosure thermal calculation, especially if the breaker sits alongside other high-current devices.