SENTRON 3VA1225-4EF32-0AH0 — 250 A MCCB for Line Protection
The Siemens 3VA1225-4EF32-0AH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It carries a 250 A continuous rating at 40 °C and a 121 kA interrupting capacity at 240 V, making it suitable for high-fault service-entrance or feeder applications where SCCR headroom is critical. The 3-pole frame with a TM240 thermal-magnetic release provides both overload and short-circuit protection in a single device. Rated insulation voltage is 800 V, and the breaker dissipates 57 W maximum at full load — a figure to account for in enclosure thermal calculations, especially when grouping multiple breakers in a compact panel.
Interrupting Ratings Across Voltages
The interrupting capacity varies with system voltage: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, 17 kA at 500 V, and 11.9 kA at 690 V. For a 400 V distribution board, the 75.6 kA figure at 415 V is the relevant coordination point — verify that downstream breakers are selectively coordinated within that fault window.
Thermal Derating and Ambient Temperature
The breaker holds 250 A continuously from 40 °C through 50 °C (–). Above 50 °C, derating applies: 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. Operating ambient range is -25 °C to 70 °C (–); storage range is -40 °C to 80 °C (–). If the panel ambient exceeds 50 °C, the load must be reduced accordingly.
Auxiliary Switching and Indication
The breaker ships with 2 auxiliary switches plus 1 trip alarm switch (HQ) factory-fitted. A trip indicator is present. No undervoltage release, no ground-fault monitoring, and no communication function are included on this variant — those are separate option adders if needed.
Physical Fit and Panel Integration
Dimensions are 105 mm wide, 158 mm high, and 70 mm deep. The 105 mm width is a 3-pole frame size — verify busbar spacing and enclosure cutout against the existing panel layout. The supplied basic switch is order code 3VA12254EF320AA0.