The Siemens SENTRON 3VA1225-1AA42-0AA0 is a 4-pole switch disconnector in MCCB design, rated for 250 A continuous current at 40 °C through 50 °C without derating. It is a pure disconnecting means — no overload or short-circuit protection built in, per the product description. The 70 mm depth and 140 mm width fit standard MCCB panel cutouts, and the front terminal busbar connection keeps wiring clean in a distribution board.
Thermal derating and power loss
The 250 A rating holds flat from 40 °C to 50 °C ambient. Above that, the derating curve drops linearly: 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. Maximum power loss is 57 W at full load — a meaningful figure for enclosure thermal calculations, especially in a sealed IP40 panel. The operating temperature range is -25 °C to +70 °C, with storage from -40 °C to +80 °C.
Integration notes
Mounts on a panel or enclosure backplate via the MCCB footprint: 158 mm height, 140 mm width, 70 mm depth. Busbar connection on the front terminals — no rear or plug-in option listed. The IP40 front protection means it is suitable for indoor distribution panels where splash or dust ingress is minimal. An optional motor drive (product extension) is available for remote switching. No auxiliary contacts, undervoltage release, or communication function are built in; those would need external modules.