DC switch disconnector for distribution — 400 A, 750 V DC
The Schneider Electric C404400DS is a ComPacT NSX400NA DC switch disconnector, 4-pole, fixed-mount, rated 400 A at 750 V DC in DC-22A utilisation category. That DC-22A rating means it's designed for switching DC motor loads and resistive-inductive DC circuits — not just a simple on/off isolator. The 750 V DC insulation voltage (Ui) and operational voltage (Ue) are the same figure, so the part is fully rated at that voltage without derating. It's suitable for isolation per EN/IEC 60947-3, with a visible contact position indicator and a toggle control.
Rated short-time withstand current (Icw) is 7.5 kA for 1 second — that's the fault current the disconnector can carry without damage while a downstream breaker clears. The short-circuit making capacity (Icm) is also 7.5 kA as a switch-disconnector alone, so it can close onto a fault at that level. Rated impulse withstand voltage (Uimp) is 8 kV, which covers typical distribution transients.
Physical integration and environment
Fixed-mount on a backplate — no DIN-rail clip, so plan for drilled mounting holes at 45 mm connection pitch. Dimensions: 255 mm high, 185 mm wide, 110 mm deep. IP40 enclosure protection means it's safe against tools and small wires but not water ingress; IK07 impact resistance handles light mechanical shock. Front connections on both upside and downside simplify busbar or cable routing in a panel. Class II electrical shock protection means no earth connection required for the enclosure.