What this MCCB brings to the panel
The Siemens SENTRON 3VA1025-4ED32-0KA0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection in distribution panels. It carries a 25 A continuous rating at 40 °C and delivers a 121 kA interrupting capacity at 240 VAC — that's the short-circuit current it can safely clear without welding its contacts or rupturing the case. At 415 VAC it still handles 75.6 kA, and at 690 VAC it holds at 11.9 kA, so it covers both low-voltage commercial and industrial service-entrance duty. The overcurrent release is a TM210 thermal-magnetic type, which means it uses a bimetal strip for overload protection and a solenoid for short-circuit response — no electronic trip unit, so no auxiliary power needed for the trip function. A built-in shunt trip (STL) allows remote opening via a control signal, useful for emergency-stop or interlock circuits.
Breaking capacity across voltages — where it fits
This MCCB's interrupting rating drops as voltage rises: 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 11.9 kA at 690 V is the floor — it's still adequate for most 690 V industrial feeders, but if your fault current exceeds that, you'd step up to a higher-rated frame. The rated insulation voltage is 800 V, so the internal clearances are designed for 690 V systems with margin.
Thermal derating and ambient limits
The 25 A rating holds steady up to 50 °C ambient. At 55 °C it derates to 24 A, and at 70 °C it drops to 23 A. That's a shallow derating curve — only 8% loss from 40 °C to 70 °C — so it's forgiving in a warm enclosure. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power dissipation is 8.5 W, which matters for heat buildup in a sealed panel.
Physical fit and panel integration
Dimensions: 130 mm height, 76.2 mm width, 70 mm depth. That's a standard 3-pole MCCB footprint — mounts on a DIN rail or directly to a backplate via the integral mounting clips. The 76.2 mm width (3 inches) matches the typical SENTRON 3VA frame width for 3-pole units up to 160 A, so it slots into existing panel layouts without re-drilling.