What the interrupting ratings mean for your panel
The 3VM1125-4EE36-0AA2 is a SENTRON molded case circuit breaker from Siemens, designed for line protection in distribution panels. Its interrupting capacity of 121 kA at 240 VAC means it can safely clear a fault up to that level without rupturing — critical for high-fault locations like service entrances or transformer secondaries where available fault current is high. At 415 VAC the rating drops to 76 kA, and at 500 VAC to 12 kA, so the voltage at the fault point governs the breaker's ability to interrupt.
Thermal-magnetic release and continuous current
The TM220 overcurrent release combines a thermal element for overload protection and a magnetic element for short-circuit response. Rated 25 A continuous at 40 °C ambient, it holds that rating through 50 °C, then derates to 24 A at 55 °C and 23 A at 70 °C. That thermal curve matters for panels in hot environments — a 25 A breaker in a 65 °C switchroom is effectively a 23 A device.
Panel fit and mounting
At 70 mm deep, 76.2 mm wide, and 130 mm tall, the 3-pole breaker occupies a standard MCCB footprint for DIN-rail or panel-mount installation. The IP40 front protection means the operator interface is protected against solid objects over 1 mm, but the breaker is not sealed against moisture — keep it in a dry enclosure or add a higher-rated cover if washdown is nearby.