Siemens 3VA1225-4EF42-0AD0 — 250 A SENTRON MCCB
The Siemens 3VA1225-4EF42-0AD0 is a 4-pole SENTRON molded case circuit breaker rated for 250 A continuous current at 40 °C ambient, with a TM240 thermal-magnetic overcurrent release.
The interrupting rating drops sharply as line voltage rises: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, 17 kA at 500 V, and 11.9 kA at 690 V. For a 480 V panel the relevant figure is the 440 V or 500 V column — 52.5 kA or 17 kA respectively — which still exceeds typical 480 V fault levels (usually 10–65 kA) for most commercial-industrial installations.
Above 50 °C it steps down: 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C.
Dimensions: 140 mm wide × 158 mm tall × 70 mm deep. The 70 mm depth (2.76 in) means it clears most 200–300 mm deep enclosures with room for rear-mounted busbars or cable ladders. The 4-pole body occupies 140 mm of DIN-rail or mounting-plate width — plan for a 175 mm minimum bay width to allow finger space for lug torqueing. The HQ auxiliary switch block adds roughly 18 mm to the side, so account for that in the wiring gutter.