What this MCCB is and where it fits
The 3VA1125-5GF46-0AA0 is a Siemens SENTRON 4-pole molded case circuit breaker rated 25 A continuous, built for line protection in distribution panels. The TM240 thermal-magnetic release handles overload and short-circuit trip curves, and the interrupting ratings are substantial: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 500 V and 690 V. That kind of breaking capacity means it can sit close to a high-fault transformer or upstream of a motor control center without needing a current-limiting fuse ahead of it — the MCCB clears the fault itself. The 70 mm depth, 101.6 mm width, and 130 mm height put it in a standard SENTRON 3VA frame size that bolts into a panel or mounts on a mounting plate. IP40 on the front means it's protected against solid objects over 1 mm — fine for a clean indoor switchboard, but not for washdown areas. No undervoltage release, no ground-fault monitoring, no communication function on this variant; it's a straight line-protection breaker with a mechanical trip indicator.
Thermal derating and operating range
The 25 A rating holds from 40 °C up to 50 °C; at 55 °C it derates to 24 A, and at 70 °C it's 23 A. If the panel runs hot — say, a packed enclosure with drives and contactors — factor that derating into the load calculation. The insulation voltage is rated 800 V, and the operating range is -25 °C to 70 °C, with storage from -40 °C to 80 °C. Power loss at full load is 8.5 W, which matters for thermal rise in a sealed cabinet.