MCCB with high interrupting capacity for line protection
The Siemens SENTRON 3VA2225-6JP32-0HA0 is a 3-pole molded case circuit breaker rated for 250 A continuous current at 40 °C, with a shunt trip release for remote opening. Its interrupting capacity hits 242 kA at 240 V AC and 187 kA at 415 V AC, which means it can clear high-fault currents on a distribution bus without cascading upstream — critical for selective coordination in a plant main or feeder panel. The breaker is designed for line protection (not motor or generator protection), so it trips on overload and short-circuit but lacks undervoltage or ground-fault monitoring. It includes a communication function for integration into a higher-level monitoring system. The unit measures 105 mm wide by 181 mm tall by 86 mm deep, fitting standard panel cutouts for SENTRON 3VA frames.
Thermal derating and ambient limits
The breaker holds its full 250 A rating up to 50 °C ambient. Above that, it derates linearly: 238 A at 55 °C, 225 A at 60 °C, 213 A at 65 °C, and 200 A at 70 °C. Operating ambient range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss is 48 W. If the panel runs hot — say, near a transformer or in a non-climate-controlled enclosure — the 55 °C derating to 238 A is the number to size against.
Breaking capacity across voltage levels
Interrupting ratings: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 4.5 kA at 690 V. The steep drop at 690 V (4.5 kA) is typical for an MCCB with a 250 A frame — the arc extinction limits at higher voltage. For a 480 V or 600 V class system, the 121 kA at 500 V gives ample headroom for most industrial services.