What this MCCB is and what it does
The Siemens SENTRON 3VA2225-5HN32-0KA0 is a 3-pole molded case circuit breaker (MCCB) rated for 250 A continuous current, designed for line protection in distribution panels and industrial switchboards. Its interrupting capacity scales with system voltage: 187 kA at 240 V AC, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 4.5 kA at 690 V — so at typical 480 V industrial feeds it still holds a very high 75.6 kA, giving plenty of headroom for high-fault panels. It carries a shunt trip release (STL) for remote tripping via a control signal — useful in emergency-stop circuits or supervisory shutdown sequences.
Thermal derating and real-world current
The breaker holds its full 250 A rating from 40 °C up to 50 °C ambient. Above that it derates linearly: 241 A at 55 °C, 232 A at 60 °C, 222 A at 65 °C, and 213 A at 70 °C. If your panel runs hot — say near a drive stack or in a non-ventilated enclosure — use the 55 °C or 60 °C row for sizing. Maximum power loss at rated current is 48 W, which is typical for a 250 A frame and manageable in a ventilated enclosure.
Panel fit and dimensions
The breaker measures 181 mm high, 105 mm wide, and 86 mm deep — a standard 3-pole MCCB footprint that fits most DIN-rail or panel-mount enclosures without surprises. It does not include an undervoltage release or ground-fault monitoring module; the only auxiliary release is the shunt trip. If you need UVR or GF protection, you will add external modules or choose a different variant.