The Siemens SENTRON 3VA1125-6EF32-0JA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current of 25 A at 40 °C and a breaking capacity of 220 kA at 240 V AC. That interrupting rating means it can safely clear a fault up to 220 kA without welding contacts or rupturing the case — critical for high-fault panels near large transformers or utility feeds.
Breaking capacity and selectivity
The 220 kA at 240 V is the headline number, but the full SCCR curve matters for coordination studies: 154 kA at 415 V, 121 kA at 440 V, and 17 kA at 500 V and 690 V. At 690 V it still holds 17 kA, which is respectable for a 25 A frame — many competitors drop below 10 kA at that voltage. The TM240 thermal-magnetic release provides fixed thermal and magnetic trip settings, so it's a drop-in replacement for existing 3VA panels without needing to dial in adjustable curves.
Integration and panel fit
The 3VA1125-6EF32-0JA0 mounts on a standard DIN rail or panel-mount base. At 76.2 mm wide (3 in), 130 mm tall (5.12 in), and 70 mm deep (2.76 in), it fits the same cutout as other 3VA 3-pole frames. The shunt trip (STL) auxiliary release is built in — no external relay needed for remote tripping. Rated insulation voltage is 800 V, so it's suitable for 480/277 V and 600 V systems with headroom.
Thermal derating and power loss
The 25 A rating holds flat from 40 °C to 50 °C, then derates to 24 A at 55 °C and 60 °C, and 23 A at 65 °C and 70 °C. Maximum power loss is 8.5 W — negligible for panel thermal budgeting, but worth noting if the breaker is enclosed in a non-ventilated subpanel. Storage range is -40 °C to 80 °C; operating range is -25 °C to 70 °C.