The Siemens 3VA1225-4EF42-0CH0 is a SENTRON molded case circuit breaker (MCCB) rated for 250 A continuous current (Iu) with a TM240 thermal-magnetic release — the thermal element handles overloads, the magnetic element handles short-circuits, and the 240 designation means the thermal pickup is calibrated for a 240 A frame. At 415 V the interrupting rating drops to 75.6 kA, at 440 V to 25 kA, and at 690 V to 11.9 kA — the voltage derating is normal for MCCBs, so verify your available fault current at the actual system voltage before specifying. The IP40 front protection means the breaker face is protected against solid objects over 1 mm, but the enclosure itself must provide the overall panel IP rating.
Thermal derating and endurance — the real-world limits
At 55 °C it derates to 243.3 A, at 60 °C to 236.5 A, at 65 °C to 229 A, and at 70 °C to 223 A. Mechanical endurance is rated at 15 000 operations — that's the latching mechanism life, not the electrical contact life under load, which will be lower depending on switching frequency and fault-clearing history.
Auxiliary contacts and undervoltage release — what's on board
The auxiliary contact set (2 NO/NC changeovers) reports breaker position; the trip alarm switch signals a fault trip separately from a manual open. The integrated auxiliary trip order code is 3VA9608-0BB24 if you need a replacement module.
Width 140 mm, height 158 mm, depth 70 mm. Verify gland plate cutouts and busbar spacing against these dimensions before panel layout.