What this MCCB delivers in a hot, dusty panel
The Siemens SENTRON 3VA2225-6HN32-0BL0 is a 3-pole molded case circuit breaker rated for 250 A continuous current (Iu) with an ETU350 electronic trip unit. It carries a 242 kA breaking capacity at 240 V and 187 kA at 415 V, so it handles high-fault scenarios typical of industrial mains without cascading upstream. The ETU350 release gives you adjustable long-time, short-time, and instantaneous protection curves — useful for coordinating with downstream feeders in a cement plant or refinery where selectivity matters. Rated insulation voltage is 800 V, and the breaker holds its full 250 A rating up to 50 °C ambient. Above that it derates linearly: 241 A at 55 °C, 232 A at 60 °C, 222 A at 65 °C, 213 A at 70 °C. In a control room that sits at 50 °C near the kiln, you get the full nameplate; if the enclosure is cooking at 65 °C, you still have 222 A available — no forced derating guesswork. The auxiliary contact block ships as 2 auxiliary switches + 1 trip alarm switch + 1 electrical alarm switch (HQ version). That gives you separate signals for breaker position, fault trip, and electrical status — enough to feed a PLC input card without external relays. An undervoltage release (UVR) is also included, so the breaker can be tripped remotely on loss of control voltage, which is standard for emergency-stop circuits.
Panel fit and integration
Dimensions: 105 mm wide, 181 mm high, 86 mm deep. That 86 mm depth is the body only — add clearance for the rotary handle and cable terminations. The breaker mounts on a standard DIN rail or can be screw-fixed to a backplate. Spring-cage terminals accept copper or aluminium conductors; strip length and torque values are on the nameplate. Maximum power loss is 50.5 W at full load. In a sealed enclosure that number drives internal temperature rise — account for it in the thermal design if the panel is tight.