Switch Disconnector for Isolation, Not Protection
The Siemens SENTRON 3VA1225-1AA42-0CC0 is a 4-pole switch disconnector in an MCCB-style housing, rated 250 A continuous at 40 °C through 50 °C without derating. It is designed for isolation and switching duty only — it carries no overload or short-circuit protection elements, so it functions as a manual disconnect switch, not a circuit breaker. The part includes an undervoltage release (UVR) coil rated 120–127 V AC 50/60 Hz, which will trip the switch open if control voltage drops, making it suitable for emergency-stop or undervoltage-protection schemes in a panel.
What the Ratings Mean for Fit
Rated operating voltage is 690 V AC and 600 V DC, with an insulation voltage of 800 V. The 250 A continuous rating holds flat from 40 °C to 50 °C; at 55 °C it derates to 243 A, at 60 °C to 237 A, at 65 °C to 230 A, and at 70 °C to 223 A. If your panel ambient runs above 50 °C, size up or account for the derate. The front terminal accepts busbar connection only — no cable lugs directly on the switch body. Mechanical service life is 15,000 operating cycles typical, which is adequate for isolation duty but not for frequent switching under load.
Auxiliary Configuration and Panel Fit
This variant ships with two HQ auxiliary switches (2 CO contacts) and an undervoltage release (UVR). The UVR has no leading contact.