What this MCCB is and what the ratings mean for your panel
The Siemens SENTRON 3VA2225-7HN32-0AG0 is a 3-pole molded case circuit breaker (MCCB) rated for a continuous current Iu of 250 A, configured for line protection with an ETU350 electronic overcurrent release. The 330 kA breaking capacity at 240 V tells you this breaker can safely interrupt a fault current up to that level without welding contacts or cascading failure upstream — that's the figure that governs whether it clears a high-fault scenario or the main breaker trips instead. At 415 V and 440 V it still holds 242 kA, and at 500 V it's 187 kA, dropping to 6.3 kA at 690 V, so match the available fault current at your system voltage, not just the headline number. The 250 A rating holds flat from 40 °C through 50 °C ambient — no derating needed in a typical warm panel. At 55 °C it's 241 A, at 60 °C it's 232 A, and it steps down to 213 A at 70 °C. If your enclosure runs hot, the actual continuous current you can carry is the derated value, not the nameplate 250 A. Maximum power loss is 48 W, which feeds into the panel thermal budget calculation. Dimensions are 105 mm wide, 181 mm high, 86 mm deep — a standard SENTRON 3VA frame that fits the usual DIN-rail or screw-mount panel cutout. The front carries IP40 protection, meaning tools or fingers won't contact live parts, but the breaker is not sealed against dust ingress. It ships with one auxiliary switch and one trip alarm switch (HP version) for status feedback to a PLC or annunciator panel.