PPB01CM48 is a plug-in mounted 3-phase mains monitoring relay designed for 380–480 VAC systems operating at 50–60 Hz. It monitors phase loss and overvoltage/undervoltage conditions on 3-phase (3P) or 3-phase plus neutral (3P+N) systems, with adjustable setpoints from -2% to +22% and configurable alarm delay from 0.1 to 30 seconds. The device features a single SPDT electromechanical relay output rated at 8 A @ 250 VAC (AC15), three information LEDs for status indication, and front-mounted dials for easy adjustment of undervoltage, overvoltage, and delay settings. With ultra-high harmonic immunity, wide operating temperature range (-20°C to +60°C), and IP20 protection, it is well-suited for industrial power distribution systems, motor control circuits, and critical load protection applications where reliable mains monitoring is essential.