MCCB for high-fault panel builds
The Siemens SENTRON 3VA2225-6JP32-0BC0 is a 3-pole molded case circuit breaker rated for 250 A continuous current (Iu) with an ETU550 electronic trip unit. It carries a 242 kA interrupting capacity at 240 V, stepping down to 187 kA at 415/440 V, 121 kA at 500 V, and 6 kA at 690 V — numbers that govern its placement in high-fault panels where the available fault current at the service entrance exceeds 100 kA. The 800 V rated insulation voltage (Ui) confirms it is built for 480/600 V class distribution without derating the insulation system. The ETU550 trip unit provides adjustable long-time, short-time, instantaneous, and ground-fault protection curves, plus a communication function for integration into a plant-wide power monitoring scheme. An undervoltage release (UVR) is fitted as standard — the release module is order code 3VA9608-0BB11, and the basic switch assembly is 3VA2225-6JP32-0AA0. Two HQ auxiliary switches (form C) are included for status feedback to a PLC or SCADA system.
Thermal derating and panel integration
The breaker holds its full 250 A rating from 40 °C up to 50 °C ambient. Above that, derating is linear: 238 A at 55 °C, 225 A at 60 °C, 213 A at 65 °C, and 200 A at 70 °C. In a sealed enclosure or high-ambient panel (e.g., adjacent to a transformer or drive), the 50 °C threshold is the practical limit before you lose capacity. The 105 mm width and 181 mm height fit standard SENTRON mounting footprints; depth is 86 mm including the handle and terminal covers. Maximum power dissipation is 50.5 W — plan for that heat load in the enclosure thermal calculation.