MCCB for line protection with ETU350 trip unit
The Siemens SENTRON 3VA2125-7HN32-0AA0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection, carrying a rated continuous current of 25 A across the full ambient temperature range from -25 °C to 70 °C — no derating needed up to 70 °C. Its ETU350 electronic trip unit provides adjustable overload and short-circuit protection curves, making it suitable for feeder circuits in distribution panels where coordination with downstream breakers matters.
Interrupting capacity across voltage levels
This MCCB delivers 330 kA interrupting capacity at 240 V AC, dropping to 242 kA at 415 V and 440 V, 187 kA at 500 V, and 3.7 kA at 690 V. The steep drop at 690 V is typical for a 25 A frame — the breaker is optimized for 240–500 V distribution where fault currents are highest. Rated insulation voltage is 800 V, so it can be applied in 480/277 V or 600 V systems with appropriate coordination.
Physical fit and panel integration
Dimensions are 105 mm wide, 181 mm high, and 86 mm deep — a standard 3-pole MCCB footprint that fits most DIN-rail or panel-mount enclosures without modification. The front face carries IP40 protection, adequate for enclosed distribution boards where tools or fingers won't contact live parts. Maximum power loss is 0.6 W, negligible for thermal budgeting inside a sealed panel.