Trip unit for a 400 A distribution feeder
The Schneider Electric C4047E400 is a MicroLogic 7.3 E electronic trip unit for the ComPacT NSX400...630 molded-case circuit breaker platform. It is rated 400 A at 40 °C (Ir adjustable 160...400 A) and provides LSIR protection: long-time overload (L), short-time short-circuit (S), instantaneous (I), and integrated earth-leakage (R) — all configurable through the onboard LCD display.
What the LSIR settings mean for coordination
The L protection (long-time) pick-up is adjustable 160...400 A with a delay from 15...400 s at 1.5 x Ir — that range lets you set the feeder to ride through motor inrush without nuisance tripping, while still clearing a sustained overload. The S protection (short-time) delay is 0...0.4 s with I²t on or off; turning I²t on gives inverse-time selectivity downstream, off gives fixed-time coordination. The I (instantaneous) pick-up is also adjustable, and the R (earth-leakage) is Class A, adjustable via the rotary switch on the front face.
Thermal memory and data logging
The unit also logs energy metering, time-stamped events, and demand values, accessible through the LCD or via the communication data port.
Environmental and installation limits
Rated for -25...70 °C operating ambient and -40...85 °C storage. IP40 front face. The unit is Class II double-insulated, so no separate protective-earth connection is required on the trip unit itself.