What this MCCB does on the line
The Siemens SENTRON 3VA2225-7HN32-0KC0 is a 3-pole molded case circuit breaker rated for 250 A continuous current, designed for line protection in distribution panels. Its breaking capacity reaches 330 kA at 240 V AC and 242 kA at 415 V AC, which means it can safely interrupt very high fault currents without upstream cascading — a key requirement for main feeders in industrial switchgear. The breaker includes a shunt trip release (STL) for remote tripping and two HQ auxiliary switches for status feedback to a PLC or annunciator panel. That makes it suitable for applications where emergency-off or undervoltage remote opening is required, such as ammonia compressor controls or cold-storage distribution.
Breaking capacity and thermal derating
Rated uninterrupted current holds at 250 A up to 50 °C ambient, then derates linearly to 213 A at 70 °C. In a warm enclosure — common in refrigeration machine rooms or near compressors — the 55 °C figure of 241 A is the realistic planning number. Breaking capacity drops sharply at 690 V to 4.5 kA, so this breaker is not intended for 690 V main service; it is optimised for 240–500 V distribution where it delivers 187–330 kA. Maximum power loss is 48 W — a figure to account for in enclosed panel heat budgets, especially when multiple breakers are ganged.
Mounting and integration notes
Dimensions are 105 mm wide, 181 mm high, and 86 mm deep — a standard SENTRON 3VA2 footprint that fits existing panel cutouts and busbar systems for 250 A frames. The breaker accepts plug-in or fixed connections depending on the base unit (supplied basic switch 3VA2225-7HN32-0AA0). Operating temperature range is -25 °C to +70 °C; storage range -40 °C to +80 °C. That covers cold storage and freezer applications without special derating, as long as the ambient stays above -25 °C during operation.