SENTRON 3VA Molded Case Circuit Breaker — 250 A, 4-Pole, ETU340 Trip
The Siemens SENTRON 3VA2325-7HK42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for line protection, carrying 250 A continuously across the full 40 °C to 70 °C ambient range — no derating needed as the panel warms up near the top of the enclosure. That flat thermal curve is unusual; most breakers start stepping down current above 40 °C, so this one buys headroom in a tightly packed switchboard. The ETU340 electronic trip unit handles the overcurrent protection logic. It is a solid-state release with adjustable N-conductor protection — set it to OFF, 50 %, or 100 % of the phase current depending on whether the neutral carries load or just fault current. That adjustability matters when the same breaker frame serves both distribution and feeder duty in a single panel build. Interrupting capacity is the headline number here: 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 7.5 kA at 690 V. The 330 kA figure at 240 V tells you this breaker is sized for high-fault locations — transformer secondaries, large motor control centers, or utility entrance gear where the available fault current is in the hundreds of kiloamps. At 690 V the rating drops to 7.5 kA, which is still adequate for most 690 V distribution but means you verify the point-of-fault current before committing the BOM line.
Panel Fit and Integration
The breaker measures 110 mm deep, 184 mm wide, and 248 mm tall. Depth is the critical dimension for enclosure selection. Front protection is IP40 — splash-proof from the front but not sealed. The breaker has no undervoltage release, no voltage trigger, and no communication function built in. It is a straight electromechanical line-protection device; any remote tripping or monitoring requires an external shunt trip or auxiliary switch added to the accessory slots. Maximum power loss is 37.5 W. In a multi-breaker lineup that heat adds up — account for it in the enclosure ventilation calculation, especially if the panel is sealed to IP54 or higher.