Siemens SENTRON 3VA1225-4GE42-0AA0 — 250 A MCCB, 4-Pole, TM220 Trip Unit
The Siemens 3VA1225-4GE42-0AA0 is a SENTRON-series molded case circuit breaker (MCCB) rated for 250 A continuous current, with a 4-pole configuration and a TM220 thermal-magnetic trip unit. It is designed for line protection — the primary overcurrent and short-circuit safeguard in a distribution panel or motor control center. At 240 V it interrupts up to 121 kA; at 415 V that figure drops to 75.6 kA, at 440 V to 52.5 kA, at 500 V to 17 kA, and at 690 V to 11.9 kA. Those are the numbers that decide whether this breaker holds on a high-fault transformer secondary or needs an upstream current-limiting device. The thermal derating curve is published: full 250 A up to 50 °C ambient, then 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. If the panel ambient runs hot, the continuous load must be trimmed accordingly — the datasheet curve is the binding limit, not the 250 A nameplate.
Integration and Mounting
Dimensions are 158 mm height, 140 mm width, 70 mm depth. The 140 mm width is standard for a 4-pole MCCB in the SENTRON 3VA frame — it occupies the same panel footprint as other 4-pole 3VA breakers in the 250 A class. Front protection is IP40, suitable for enclosed distribution boards where tools or fingers are the main concern. The TM220 trip unit is thermal-magnetic: the thermal element handles overload protection (inverse-time curve), and the magnetic element handles short-circuit instantaneous trip. No undervoltage release, no shunt trip, no communication function are built in — this is a plain line-protection breaker for straightforward feeder or main-switch duty.