What it is and what it does
The Siemens 3UG4625-2CW30 is a SIRIUS residual current monitoring relay with digital setting, designed for three-phase supplies. It measures residual current from 30 mA up to 40 A, with a measurable current range of 10 mA to 43 A — so it covers both sensitive ground-fault detection (down to 30 mA) and higher-leakage industrial loads. The relay is powered by a 24–240 V AC/DC control supply, making it usable across most global panel voltages without a separate power supply module.
Key ratings and what they mean for fit
The 30 mA to 40 A measuring range means this relay can detect a 30 mA ground fault (typical threshold for personnel protection) and still handle the leakage from a large motor drive or heater bank. The full-scale value is adjustable to 1.1 times the set range, giving a 10 % over-range headroom. The output contacts are rated 3 A at 250 V AC (50/60 Hz) and 0.1 A at 250 V DC — adequate for signaling a PLC input or dropping out a contactor coil, but not for direct motor switching. The relay offers delayed switching (2 seconds) to ride through nuisance trips from capacitive inrush, and includes an error memory and external reset input, so a remote PLC can clear latched faults without a panel visit.
Where it goes and how it mounts
Housed in a 22.5 mm wide enclosure (103 mm high, 91 mm deep), it snaps onto a standard 35 mm DIN rail with a screw-and-snap-on mechanism. The mounting position is any orientation, which simplifies panel layout. The terminals accept 2x (24 … 16) AWG solid or stranded wire — spring-cage or screw terminals (the spec lists both solid and stranded ranges). IP20 at the enclosure and terminals means it belongs inside a panel, not in a washdown zone. Pollution degree 3 suits industrial environments with conductive dust or occasional condensation.
Environmental and compliance notes
Operating temperature range is -25 to +60 °C; storage and transport range is -40 to +85 °C. The relay is rated for pollution degree 3 environments.