What it is and what it does
The Schneider Electric C25V42D250 is a ComPacT NSX250HB1 molded-case circuit breaker, 4-pole, rated 250 A at 40 °C with an electronic MicroLogic 2.2 trip unit. It's built to EN/IEC 60947-2, so it's certified for distribution and motor-circuit protection in industrial panels. The 85 kA Icu at 500 V AC means it can safely interrupt a fault up to that level without cascading upstream — that's the number that decides whether it holds coordination in a high-fault installation.
What the ratings mean for fit
The MicroLogic 2.2 gives you L (long-time overload), So (short-time short-circuit with fixed delay), and I (instantaneous) protection curves — all adjustable via the trip unit dials. That electronic trip means you get thermal memory that holds for 20 minutes before and after tripping, so a reclose after a hot overload won't let the conductor overheat on the second hit. The 250 A frame is the continuous rating at 40 °C; if your panel ambient runs hotter, you'll need to derate per the manufacturer's curve. Breaking capacity is 85 kA Icu at 500 V AC, 80 kA at 525 V, and 75 kA at 690 V — that's a high-interrupting rating for a 250 A frame, so it handles most industrial service-entrance or sub-feed applications without needing a current-limiting fuse upstream.
Where it goes and how it mounts
Mounts on a backplate — horizontal or vertical, flat on the back — so it's a panel-mount breaker, not a DIN-rail snap-on. The 140 mm width and 161 mm height fit standard ComPacT NSX cutouts. Front connections both top and bottom, neutral on the left. IP40 front face (IK07 impact) means it's fine inside a clean enclosure but not for washdown. Pollution degree 3 per IEC 60664-1 — that's conductive pollution, typical of industrial environments where the panel isn't sealed.