MCCB for line protection with ETU320 release
The Siemens SENTRON 3VA2225-8HL32-0AB0 is a 3-pole molded case circuit breaker rated for a continuous current Iu of 250 A, with an ETU320 electronic trip unit for line protection. Its breaking capacity reaches 440 kA at 240 V, 330 kA at 415 V, and 50.4 kA at 690 V — figures that govern fault-clearing capability at the panel's service voltage. The rated insulation voltage Ui of 800 V gives headroom for 690 V systems without derating the insulation path. The 250 A rating holds flat from 40 °C through 50 °C, then derates to 213 A at 70 °C — a thermal curve that matters when the breaker sits in a warm enclosure alongside other heat sources. The ETU320 release is a basic electronic trip with fixed settings; no voltage trigger, undervoltage release, or ground-fault monitoring is fitted on this variant.
Panel integration and dimensions
The breaker measures 105 mm wide, 181 mm high, and 86 mm deep — a standard SENTRON 3VA2 footprint that fits existing Siemens switchboard and distribution-panel cutouts. It carries two auxiliary switches (HP type) for status feedback to a PLC or annunciator panel. The front face is rated IP40, meaning tools or fingers are protected but the breaker is not sealed against water ingress; install inside a rated enclosure for washdown or outdoor environments.
Breaking capacity and selectivity
The 440 kA at 240 V and 330 kA at 415 V are the maximum prospective short-circuit currents the breaker can safely interrupt — numbers that drive coordination studies for the upstream transformer and downstream feeders. At 690 V the rating drops to 50.4 kA, which still covers most industrial 690 V distribution faults. The ETU320 release provides fixed I²t-on and I²t-off curves for selective coordination with downstream 3VA1 or 3VA2 breakers.