What this MCCB is and what it does
The Siemens 3VA2225-5KP32-0BA0 is a SENTRON molded case circuit breaker (MCCB) rated for 250 A continuous current on a 3-pole frame, fitted with the ETU850 electronic trip unit. It's a line-protection device — meaning it's configured for feeder and main breaker duty rather than motor branch-circuit protection. The ETU850 gives you adjustable long-time, short-time, instantaneous, and ground-fault pickup settings, plus communication capability for power monitoring and remote trip indication. The 800 V rated insulation voltage (Ui) means it's comfortable on 480 V and 600 V class systems with headroom.
Breaking capacity — what the numbers mean for your fault duty
This breaker carries 187 kA at 240 V, 121 kA at 415 V and 440 V, 79 kA at 500 V, and 5.1 kA at 690 V. Those are the interrupting ratings at each voltage — the maximum fault current the breaker can safely clear without welding contacts or rupturing the case. For a 480 V panel with a 100 kA available fault current, this breaker has 21 kA of margin at 440 V (the nearest published point). At 690 V the rating drops to 5.1 kA, so if you're on a 600 V or 690 V system, verify your available fault current is under that threshold.
Thermal derating — don't size by the 250 A label alone
The 250 A continuous rating holds at 40 °C, 45 °C, and 50 °C. At 55 °C it derates to 238 A, at 60 °C to 225 A, at 65 °C to 213 A, and at 70 °C to 200 A. If this breaker lives in a non-air-conditioned enclosure or near other heat sources, use the 55 °C or 60 °C column for your continuous load calculation. The maximum power loss is 50.5 W — that's the heat you need to vent from the enclosure.
Panel fit and integration notes
Dimensions are 105 mm wide, 181 mm high, and 86 mm deep — a standard 3-pole MCCB footprint that fits SENTRON 3VA2 mounting plates and busbar systems. The breaker ships without auxiliary contacts (auxiliary contact version: without), so if you need status feedback to a PLC or SCADA, order the 3VA9608-0BB11 auxiliary trip block separately. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The mechanical endurance is 20,000 operations — typical for a main breaker that cycles infrequently.