What this part is and what it carries
The SENTRON 3VA1225-1AA42-0BB0 is a 4-pole switch disconnector on the IEC frame 250, rated at 250 A, without overload or short-circuit protection — it's a straight disconnect, not a breaker. The order code includes an undervoltage release (24 V DC) and two auxiliary changeover switches, plus a nut keeper kit for the front terminals. This is a load-break switch for isolation and switching duty, sized for a 250 A circuit.
What the ratings mean for fit
The 250 A rating on the IEC frame 250 means this switch handles full-load current for a 250 A feeder or large motor circuit — it's a disconnect, not a protective device, so it sits downstream of a breaker or fuse. The 4-pole configuration (3 phases + neutral) suits three-phase distribution panels where neutral switching is required. The undervoltage release (24 V DC) drops the switch on loss of control voltage, typical for emergency-stop or undervoltage protection schemes. Two auxiliary changeover contacts give status feedback to a PLC or status lamp without extra wiring.