What it is and where it fits
The Siemens SENTRON 3VA2025-8JQ42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated at 25 A continuous current across the full ambient range up to 70 °C, with an ETU560 electronic trip unit for line protection. It carries a breaking capacity of 440 kA at 240 V AC, 330 kA at 415 V and 440 V, 220 kA at 500 V, and 52.5 kA at 690 V — figures that place it squarely in high-fault-current distribution panels, typically downstream of a transformer or in a main feeder position where available fault current is substantial. The 140 mm width and 181 mm height fit standard SENTRON 3VA switchboard mounting; the 86 mm depth leaves room for rear-access cabling in a typical enclosure.
What the ratings mean for your panel
The 25 A rating holds flat from 40 °C through 70 °C — no derating curve to calculate for elevated ambient inside a crowded cabinet. The ETU560 electronic trip unit provides adjustable long-time, short-time, instantaneous, and ground-fault protection (summation current formation L + N conductor), which is the standard for selective coordination in industrial distribution. The 800 V rated insulation voltage (Ui) confirms suitability for 690 V systems with margin. The IP40 front protection means the breaker face is protected against solid objects over 1 mm but not against water ingress — mount in a dry location or specify a higher-IP enclosure. The power loss of 0.5 W maximum is negligible for thermal budgeting.