What it is and what it does
The Siemens SENTRON 3VA1125-4ED42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated 25 A at 40 °C, designed for line protection in distribution panels. Its TM210 thermal-magnetic release handles overload and short-circuit curves without electronic adjustment — a fixed-trip design suited for straightforward feeder protection where selectivity is set by frame sizing rather than dials.
Breaking capacity — what the numbers mean
This MCCB delivers 121 kA interrupting capacity at 240 V AC, dropping to 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 500 V and 690 V. The 121 kA figure at 240 V means it can safely clear a fault current of that magnitude without rupturing — critical for high-fault installations near large transformers. At 415 V (common in European industrial networks), the 75.6 kA rating still covers most panelboard main-breaker needs. The steep drop above 500 V reflects the physics of arc extinction in air; for 690 V systems, verify the available fault current stays under 11.9 kA to avoid coordination failure.
Thermal derating and operating range
Rated 25 A continuously from 40 °C through 50 °C ambient. Derating begins at 55 °C (24 A), holds through 60 °C, then drops to 23 A at 65 °C and 70 °C. The operating ambient range is -25 °C to +70 °C, with storage from -40 °C to +80 °C. The 8.5 W maximum power loss at full load matters for enclosure heat budgeting — in a sealed panel with multiple breakers, that waste heat adds up.
Lifecycle and sourcing reality
Current production (lifecycle stage: current). No end-of-life notice. Sourced and quoted to order against an RFQ.
Physical fit and panel integration
Dimensions: 130 mm height, 101.6 mm width, 70 mm depth. Four-pole frame. Front IP40 rating.