Siemens SENTRON 3VA1225-6EF32-0CH0 — 250 A MCCB with High Breaking Capacity
The Siemens SENTRON 3VA1225-6EF32-0CH0 is a 3-pole molded case circuit breaker (MCCB) rated at 250 A at 40 °C, designed for line protection in industrial and commercial power distribution. Its breaking capacity steps from 220 kA at 240 V down to 17 kA at 690 V, so it handles high-fault-current scenarios at lower voltages while still clearing faults at higher system voltages — a key spec for selectivity coordination studies in large panels. Thermal derating is published across the full operating range: it holds 250 A continuously from 40 °C up to 50 °C, then steps down to 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. That means in a tightly packed enclosure running at 60 °C ambient, you need to budget for 237 A continuous — not the nameplate 250 A. Rated insulation voltage is 800 V, and maximum power loss is 59.5 W — a figure to check against enclosure thermal rise calculations, especially when multiple breakers share a compartment.
Dimensions & Panel Fit
Physical footprint: 105 mm wide, 158 mm high, 70 mm deep. That width is a standard 3-pole MCCB form factor for 250 A class — it fits most DIN-rail or bolt-on panel layouts without surprises. The 70 mm depth leaves clearance behind the door for wiring and auxiliary modules.
Built-in Auxiliaries & Releases
This variant ships with an undervoltage release (UVR) fitted, plus two auxiliary switches and one trip alarm switch (HQ). The UVR is factory-installed, not a field-add kit — verify your control voltage matches the release rating before installation. The trip indicator is also present, giving a visible flag on the breaker face after a fault trip.