The Schneider Electric ENW21428 is a microprocessor-based control unit for the EasyPact NW range of air circuit breakers. It carries a Trip System 6.0A with LSIG protection — long-time, short-time, instantaneous, and ground-fault — covering the full 800 to 4000 A trip rating range at 690 V AC, 50/60 Hz, per IEC 60947-2.
What the LSIG protection curve means for your feeder
LSIG gives you four independently adjustable protection elements: long-time pickup (Ir) from 0.4 to 1 x In with nine settings and delay adjustable 0.5 to 24 s at 6 x Ir; short-time pickup (Isd) from 1.5 to 10 x Ir with nine settings and delay 100 to 400 ms; instantaneous pickup (Ii) from 2 to 15 x In, also nine settings, with an Off position for coordination schemes; and ground-fault pickup (Ig) adjustable from 0.2 to 1 x In for frames up to 1000 A, or 500 to 1200 A for larger frames, with five delay settings.
Integration into the EasyPact NW frame
This control unit mounts fixed into the EasyPact NW breaker chassis — no DIN rail, no panel cutout. The 75 mm depth, 55 mm width, and 200 mm height fit the standard NW drawout cradle. Neutral position is left-side; the unit supports 3-pole (3D), 4-pole (4D), and 3D + N/2 configurations, with neutral protection selectable as unprotected, 0.5 x Ir, or 1 x Ir. Zone selective interlocking (ZSI) is built in, so you can daisy-chain multiple breakers for faster fault isolation on a bus tie scheme.
Thermal memory and fault diagnostics
The Trip System 6.0A retains a thermal model of the conductor temperature for 20 minutes before and after a trip event. That prevents immediate reclose onto a still-hot cable — useful on motor feeders where repeated starts can overheat the branch circuit. The digital display shows the cause of the last trip: internal fault, short-circuit, overload, or earth fault, which cuts troubleshooting time on a downed line.