What this MCCB delivers — and where the ratings matter
The Siemens SENTRON 3VA2225-5KP32-0AC0 is a 3-pole molded case circuit breaker (MCCB) rated for 250 A continuous current, fitted with an ETU850 electronic trip unit. The headline breaking capacity is 187 kA at 240 VAC — that's the fault current it can safely interrupt at the lowest system voltage, which typically governs the main breaker in a 208/240 V panel. At 415 V and 440 V it still holds 121 kA, dropping to 79 kA at 500 V and 5.1 kA at 690 V. For a sourcing decision: at 240 V this breaker sits in the high-interrupting class, suitable for large transformer-fed services or high-fault industrial feeds where SCCR headroom is non-negotiable.
Thermal derating and continuous current — what the curve tells you
The 250 A rating holds flat from 40 °C through 50 °C ambient — no derating needed in a typical 40 °C panel. At 55 °C it drops to 238 A, at 60 °C to 225 A, and at 65 °C to 213 A, hitting 200 A at 70 °C. If the breaker lives in a non-ventilated enclosure near other heat sources, plan for the 55 °C derated value as your practical continuous limit. The maximum power loss is 48 W, which feeds into enclosure thermal calculations.
ETU850 trip unit and auxiliary contacts
The ETU850 is an electronic trip unit with communication function (yes, this variant supports it) and other measurement functions — meaning it can report current values and event logs over the integrated comms link, not just trip. The breaker ships with 2 auxiliary switches (HQ type) for status feedback to a PLC or SCADA. There is no undervoltage release, no voltage trigger, and no ground-fault monitoring on this configuration; those are separate order-code variants. The trip indicator is not fitted, so visual flag at the breaker face is absent — rely on the aux contacts or comms for trip status.
Panel fit and environmental limits
Dimensions are 86 mm deep, 105 mm wide, 181 mm tall — a standard MCCB footprint for 250 A frame size. Front protection is IP40, meaning tools and fingers are kept out but the breaker is not sealed against water ingress; mount inside a panel with a higher enclosure rating. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C. The rated insulation voltage is 800 V, so it is suitable for 690 V systems with margin.