What it is and what it does
The Siemens 3VA1125-4GE46-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for 25 A continuous current across a 4-pole configuration. It's designed for line protection — meaning it sits upstream protecting a feeder or distribution bus, not a specific motor or device. The interrupting ratings tell you where this breaker can live on the fault-current map: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. That 121 kA figure at 240 V is the headline — it means this breaker can safely clear a fault on a high-capacity transformer secondary without needing a current-limiting fuse upstream.
Ratings and what they mean for the panel
The TM220 overcurrent release is a thermal-magnetic trip — the thermal element handles overloads (slow response to sustained overcurrent), the magnetic element handles short circuits (instantaneous). It's the standard release for general distribution; no electronic adjustment, no communication module. Temperature derating is minimal up to 50 °C — the breaker holds full 25 A rating. At 55 °C it drops to 24 A, and at 70 °C it's 23 A. That means in a hot panel near the top of an enclosure you still get 92% of rated current, which is better than many MCCBs that start derating at 40 °C. Rated insulation voltage is 800 V, so the breaker's internal clearances and creepage are designed for 690 V systems with margin. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. IP40 on the front means it's protected against tools and small wires (1 mm) but not against water ingress — standard for a panel-mounted MCCB behind an enclosure door.
Integration notes
Mounts on a DIN rail or panel-mount base. Dimensions are 101.6 mm wide (4 inches), 130 mm tall, 70 mm deep — standard 4-pole MCCB footprint for the 3VA frame size. No undervoltage release, no trip indicator, no ground-fault monitoring on this variant. Power loss is 8.5 W maximum at rated current — factor that into enclosure thermal calculations if the panel is densely populated.