Trip unit selection for ComPacT NSX160
The Schneider Electric C1634A160 is a MicroLogic 4.2 AL electronic trip unit for the ComPacT NSX160 frame, rated 160 A at 40 °C. It provides LSoI protection — long-time overload (L), short-time short-circuit with fixed delay (So), and instantaneous short-circuit (I) — plus integrated earth-leakage protection (Class A). The trip unit is field-installable in the fixed-mounted NSX160 breaker; the 3D protected poles cover all three phases plus neutral for earth-leakage sensing.
The long-time pick-up Ir is adjustable from 63 A to 160 A in nine steps, so the same trip unit can serve a 100 A or 125 A feeder simply by dialing the Ir setting. Short-time pick-up Isd adjusts from 1.5 to 10 times Ir, giving you selectivity headroom against downstream breakers. Instantaneous pick-up Ii is fixed at 2400 A — that's 15× the 160 A rating, which keeps it above motor inrush and lets downstream devices clear first. Earth-leakage sensitivity IΔn is adjustable (the evidence does not list the range, but the trip unit carries a rotary switch to set it), and the time delay Δt can be set from 0 ms (instantaneous) up to 1 s, allowing coordination with downstream RCDs.
Integration notes
The trip unit snaps into the ComPacT NSX160 breaker's front cradle — no tools needed for installation or removal. The breaker itself is fixed-mounted (not plug-in), so the assembly occupies a standard panel cutout. IP40 front-of-panel protection is sufficient for clean indoor switchboards; pollution degree 3 per IEC 60947-1 means it tolerates conductive pollution in industrial environments.