The Siemens SIRIUS 3UG4624-1CS20 is a residual current monitoring relay with digital setting, designed for three-phase supplies. It covers an adjustable measuring range from 30 mA to 40 A, making it suitable for detecting leakage currents across a wide span — from sensitive earth-fault detection on smaller circuits up to higher-level monitoring on larger feeders.
Key Ratings and Their Meaning
The measurable current range of 30 mA to 40 A (adjustable) is the core selection parameter: set the trip threshold to match the system's acceptable leakage — for example, 30 mA for personnel protection on a final circuit, or several amps for equipment-level monitoring on a main feeder. The relay operates on AC voltage supplies from 90 V to 690 V at 50/60 Hz, so it works across common global line voltages (e.g., 110 V, 230 V, 400 V, 690 V) without a separate power supply module. Output contacts are rated for switching: 3 A at 250 V AC and 3 A at 400 V AC (50/60 Hz), and 1 A at 24 V DC, 0.2 A at 125 V DC, 0.1 A at 250 V DC. This covers typical PLC or contactor coil loads. The relay includes an error memory function and supports external reset, which is useful for remote fault acknowledgment in unattended panels. The IP20 protection rating requires installation inside an enclosure that provides at least IP54 or better.
The 22.5 mm width (one standard modular unit) allows dense packing in the cabinet. Any mounting position is permitted, which simplifies panel layout.