The Siemens SENTRON 3VA2125-5HN46-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 25 A continuous current, with an ETU350 electronic trip unit. It's designed for line protection in distribution panels and motor control centers, where you need adjustable overload and short-circuit protection in a compact frame. Breaking capacity is the headline number here: 187 kA at 240 V AC, 121 kA at 415/440 V, and still 75.6 kA at 500 V. That's high-interrupting capacity for a 25 A frame — it handles fault currents that would vaporize a standard MCCB, so it's a good fit for large transformer secondaries or high-capacity bus risers where available fault current is stiff. At 690 V the rating drops to 3.7 kA, which is typical for a 4-pole device in a wye configuration — the per-pole voltage stress limits the interrupt rating. If your system is 690 V, verify the available fault current stays under that threshold.
Thermal performance and continuous rating
The 25 A continuous rating holds flat from 40 °C all the way to 70 °C ambient — no derating needed across the normal operating range. That's unusual for a molded case breaker; most lose 10–20 % by 60 °C. The ETU350 electronic trip compensates for ambient temperature, so you don't have to oversize the frame for a warm panel. Power loss is only 0.6 W maximum — negligible for panel heat calculations. The insulation voltage rating is 800 V, so it's comfortable on 480/277 V and 600 V systems with margin.
Physical fit and panel integration
Dimensions are 140 mm wide, 181 mm high, and 86 mm deep. The 140 mm width is standard for a 4-pole SENTRON 3VA2 frame — it occupies the same footprint as other 4-pole breakers in the series, so swapping between ratings in the same panel doesn't require re-drilling the mounting plate. Front-face protection is IP40, meaning tools and fingers are kept out but the breaker isn't sealed against water ingress. This is standard for panel-mounted MCCBs — the enclosure provides the environmental seal.