What this MCCB carries in the nacelle
The Siemens 3VA1025-3ED42-0AA0 is a SENTRON molded case circuit breaker (MCCB) built for line protection — the primary feed breaker in a distribution panel, not a motor-protection device. Four poles, rated 25 A continuous at 40 °C, with a TM210 thermal-magnetic release that handles overloads and short-circuits without an external trip unit. The interrupting capacity tells the real story: 75.6 kA at 240 V, 52.5 kA at 415 V, and still 7.5 kA at 690 V — numbers that matter when you're coordinating downstream feeders in a turbine's low-voltage switchgear or an industrial MCC lineup.
Ratings that decide the fit
The 25 A rating holds flat from 40 °C to 50 °C, then derates gently to 23 A at 70 °C — no surprise derating curve for a panel that runs warm. Insulation voltage is 800 V, so the breaker is comfortable in 480 V and 600 V class systems with headroom. Power loss maxes at 8.5 W; four poles dissipating that in a sealed enclosure needs a thermal check, but in a ventilated panel it's fine. Operating temperature spans -25 °C to 70 °C, storage from -40 °C to 80 °C — the storage range is the one that governs a spare sitting on a shelf in an unheated turbine tower.
Panel fit and integration
Dimensions are 130 mm high, 101.6 mm wide, 70 mm deep — a 4-pole frame that fits standard Siemens 3VA mounting footprints. IP40 on the front face means it's protected against tools and solid objects larger than 1 mm; no water ingress rating, so keep it inside a panel, not exposed to washdown. No undervoltage release, no communication function, no ground-fault monitoring on this variant — it's a straight thermal-magnetic line protection breaker with no accessories fitted.