MCCB for high-fault panels — 250 A, ETU320, 3-pole
The Siemens SENTRON 3VA2225-8HL32-0CA0 is a 3-pole molded case circuit breaker rated for 250 A continuous current, configured as a line protection device with an ETU320 electronic overcurrent release. At 240 V it interrupts fault currents up to 440 kA, dropping to 330 kA at 415 V and 440 V, 242 kA at 500 V, and 50.4 kA at 690 V — figures that place it in the high-breaking-capacity tier for main feeder or large subfeed applications where upstream transformer or generator fault levels are substantial. The ETU320 release provides adjustable thermal-magnetic or electronic trip curves depending on the variant; this unit ships as the line protection version, meaning it is set for cable and busbar protection rather than motor or generator duty. The rated insulation voltage of 800 V covers 690 V systems with margin.
Thermal derating and panel fit
The 250 A rating holds flat from 40 °C through 50 °C ambient — no derating needed in a typical 40 °C switchroom. At 55 °C it steps to 241 A, then drops linearly to 213 A at 70 °C. If the panel sits near a heat source or in a non-conditioned enclosure, size the downstream conductor and bus for the derated value at the actual ambient. Dimensions are 105 mm wide, 181 mm tall, and 86 mm deep — a standard SENTRON 3VA frame footprint. It mounts on a DIN rail or directly to a backplate via the screw terminals. The unit includes an undervoltage release (UVR) as the auxiliary release; there are no auxiliary contacts or communication module on this order code, so any status feedback to a PLC requires an external auxiliary switch block added in the field.
Selectivity and coordination notes
With 440 kA breaking capacity at 240 V and 330 kA at 415 V, this MCCB can be applied downstream of a larger 3VA frame or upstream of smaller 3VA or 5SY MCBs while maintaining full selectivity — the ETU320's adjustable I²t curve allows coordination studies. Maximum power loss is 50.5 W at rated current, which should be included in the enclosure thermal calculation. The unit has no phase-failure detection and no ground-fault monitoring — those functions require a different release variant or an external module. The latching endurance is rated at 20,000 operations, adequate for infrequent switching applications like main disconnect or backup generator feeder.