What this control unit does
The ENW21433 is the Trip System 2.0E control unit for Schneider Electric's EasyPact NW range of drawout air circuit breakers. It provides LI protection — long-time overload and instantaneous short-circuit — with a trip unit rating adjustable from 800 to 4000 A. The microprocessor-based electronics include a digital display, energy metering, and fault indication for overload, short-circuit, earth fault, and internal faults. The 20-minute thermal memory before and after tripping means the unit remembers the heating history of the conductors, so a reclose after a near-trip won't let the cable overheat on the second hit.
The long-time pickup (Ir) adjusts from 0.4 to 1.0 x In across 9 settings, and the long-time delay (Tr) ranges from 0.5 to 24 s at 6 x Ir with a -0 to -20 % accuracy band. Instantaneous pickup (Ii) goes from 1.5 to 10 x Ir, also 9 settings. For a 2000 A frame breaker, that means the instantaneous trip point can be set anywhere from 3000 A to 20,000 A — useful for coordinating with downstream feeders without nuisance tripping on motor inrush.
This is the drawout version of the control unit — it plugs into the EasyPact NW breaker cradle, not hard-wired. The neutral position is left-side. Protected poles can be configured as 3D, 4D, or 3D + N/2, and neutral protection settings include without protection (3D), 0.5 x Ir (3D + N/2), or 1 x Ir (4D). Zone selective interlocking (ZSI) is built in, so multiple breakers in a cascade can communicate to clear a fault faster without losing coordination. Dimensions: 200 mm high, 75 mm deep, 55 mm wide — fits the standard EasyP NW drawout cassette.