MCCB with 121 kA interrupting capacity at 240 V
The Siemens 3VA1125-4EF32-0CA0 is a SENTRON molded case circuit breaker (MCCB) rated for 25 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. Its interrupting capacity reaches 121 kA at 240 V, 75.6 kA at 415 V, and 52.5 kA at 440 V — figures that govern fault-clearing capability in high-fault panels. The 3-pole design and 800 V rated insulation voltage (Ui) suit it for 400 V three-phase distribution. An integrated undervoltage release (UVR) trips the breaker when control voltage drops; the auxiliary trip order code 3VA9608-0BB24 is specified for the internal release mechanism. No auxiliary contact version is fitted as standard.
Thermal derating and panel fit
The 25 A rating holds at ambient temperatures up to 50 °C; above that it derates to 24 A at 55 °C, 23.5 A at 60 °C, 23 A at 65 °C, and 22.5 A at 70 °C. Operating range is -25 °C to 70 °C, storage from -40 °C to 80 °C. The 70 mm depth and 76.2 mm width fit standard MCCB mounting footprints in distribution panels. Front protection is IP40 — suitable for enclosed panel mounting where no water ingress is expected. No communication function, phase failure detection, or ground fault monitoring is built in.