This MicroLogic 4.2 4d electronic trip unit is a 4-pole 4d trip unit used on ComPacT NSX 100/160/250 circuit breakers. This 40A rated electronic trip unit is an optimal choice for all standard and special applications. It has adjustable long-term protection against overloads. It also offers adjustable short-term protection and fixed instantaneous short-circuit protection. The MicroLogic 4.2 Vigi trip unit offers integrated, adjustable residual current protection. MicroLogic 4.2 indicates overloads with alarm LEDs. The green Ready LED flashes when the circuit breaker is ready to trip. A residual current pre-alarm can be available remotely by installing the optional SDx module (LV429532). This product is part of our EcoStruxure Power architecture when combined with the PowerTag NSX and ComPacT NSX basic switches.