What this MCCB does — and the ratings that decide fit
The Siemens 3VA2225-5KP32-0HL0 is a SENTRON 3VA2 molded case circuit breaker (MCCB) rated for 250 A continuous current (Iu) at 40 °C, with a 3-pole configuration and an electronic trip unit (ETU850). It is configured for line protection — the primary feeder or main breaker role in a distribution panel. The interrupting rating hits 187 kA at 240 V AC, dropping to 121 kA at 415 V and 440 V, 79 kA at 500 V, and 5.1 kA at 690 V. That 187 kA figure at 240 V is high enough for most secondary substation or large industrial service-entrance applications where available fault current is substantial. The rated insulation voltage (Ui) is 800 V, so the breaker can be used in 480/277 V or 600 V systems with adequate clearance. The ETU850 electronic trip unit provides adjustable long-time, short-time, instantaneous, and ground-fault protection curves — typical for selective coordination in a main-tie-main or feeder-breaker application. The breaker also includes a shunt trip (STL) auxiliary release, two auxiliary switches, one trip alarm switch, and one electrical alarm switch (HQ configuration), which covers remote status and trip indication. Communication function is onboard, meaning it can integrate with a BMS or SCADA system for power monitoring and remote tripping. The thermal derating curve is published: 250 A continuous up to 50 °C, then 238 A at 55 °C, 225 A at 60 °C, 213 A at 65 °C, and 200 A at 70 °C. If the panel ambient runs above 50 °C, the continuous current must be reduced accordingly. The operating temperature range is -25 °C to 70 °C, with storage from -40 °C to 80 °C. Maximum power loss is 48 W per pole — a consideration for ventilation in a sealed enclosure.
Panel integration and wiring
The breaker footprint is 105 mm wide, 181 mm tall, and 86 mm deep. It mounts on a DIN rail or can be screw-fixed to a backplate. The 105 mm width is a 4-module (4 x 27 mm) form factor typical of 250 A frame MCCBs — plan for that slot width in the panel layout. The depth of 86 mm includes the handle and arc-chamber protrusion; allow clearance for cable bending radius and the shunt trip wiring. The auxiliary contact block (2 aux + 1 trip alarm + 1 electrical alarm) and the shunt trip (STL) are factory-integrated, so no field-assembly of those accessories is needed.