What this MCCB carries and where it fits
The Siemens 3VA2225-5HN32-0BH0 is a SENTRON molded case circuit breaker (MCCB) rated for 250 A continuous current (Iu) across three poles, with an ETU350 electronic trip unit configured for line protection. Its interrupting capacity reaches 187 kA at 240 V and 121 kA at 415 V, which means it can clear high-fault currents in a main distribution panel without upstream fuses needing to open first — a key selectivity consideration for the site electrical engineer. The breaker carries an undervoltage release (UVR) as the auxiliary release type, plus a factory-integrated auxiliary trip switch (order code 3VA9608-0BB11) and a supplied basic switch (3VA2225-5HN32-0AA0). The auxiliary contact configuration is two auxiliary switches plus one trip alarm switch (HQ version), giving the panel builder a clean way to signal breaker state back to a PLC or status lamp without adding external relays. Dimensions are 86 mm deep, 105 mm wide, and 181 mm tall — a standard 3-pole MCCB footprint that fits Siemens SENTRON mounting plates and most DIN-rail adapter kits. The operating temperature range is -25 °C to 70 °C, with storage from -40 °C to 80 °C, so it handles unheated warehouses or outdoor enclosures as long as the ambient inside the panel stays within the derating curve.
Derating and thermal management
At 40 °C, 45 °C, and 50 °C the breaker holds the full 250 A rating. At 55 °C it derates to 241 A, at 60 °C to 232 A, at 65 °C to 222 A, and at 70 °C to 213 A. Maximum power loss is 50.5 W — enough heat that the panel OEM should account for it in the thermal budget, especially when multiple breakers are ganged in a row without ventilation gaps.
Interrupting ratings across voltages
The breaker's interrupting capacity (Icu) varies with system voltage: 187 kA at 240 V, 121 kA at both 415 V and 440 V, 79 kA at 500 V, and 5.1 kA at 690 V. The steep drop at 690 V means this is primarily a 480 V class device; for 690 V applications the available fault current must be verified against the 5.1 kA limit. Rated insulation voltage is 800 V, so the internal clearances support the higher voltage even though the interrupting rating is lower there.