What this MCCB is and what it does
The Siemens 3VA2025-8JQ36-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It is a 3-pole unit rated for 25 A continuous current, with an adjustable thermal-magnetic trip that can be set between 38 A and 300 A — meaning you dial in the overload pickup to match the downstream cable or load, not the other way around. Breaking capacity is the real differentiator here: 440 kA at 240 V AC, 330 kA at 415 V, and still 220 kA at 500 V. That puts it squarely in the high-fault-current category — think industrial substations or transformer secondaries where the available fault current is well above what a standard 25 A frame can handle.
Ratings that matter for the panel builder
At 690 V the breaking capacity drops to 52.5 kA — still respectable, but if your system runs at that voltage, verify the available fault current against this curve. The insulation voltage is rated 800 V, so the breaker itself is comfortable at 690 V; the limit is the interrupting capability at that voltage. The thermal-magnetic trip holds its 25 A rating across the full ambient range from -25 °C to 70 °C — no derating needed up to 70 °C, which simplifies panel layout in hot enclosures or near other heat sources. Power loss is only 0.5 W, negligible for thermal budgeting.
Physical fit and panel integration
Dimensions are 86 mm deep, 105 mm wide, 181 mm tall — a standard 3-pole MCCB footprint that fits most DIN-rail or panel-mount enclosures without surprises. The 105 mm width matches the typical 3-pole frame spacing, so it drops into a cutout or busbar system designed for that pitch.
Communication and monitoring features
This breaker includes a communication function and supports summation current ground-fault monitoring on the L-conductor. No undervoltage release or voltage-triggered trip is built in.