SIEMENS SIRIUS 3UG5625-1CW30 Residual Current Monitoring Relay, AC/DC Sensitive, 24-240 V AC/DC, 1 Channel, Digital LCD, 2 Change-over Contacts

Residual current monitoring relay from the SIRIUS 3UG5 series, engineered for precise AC/DC sensitive (Type B) earth fault detection in industrial power systems. This device continuously monitors residual currents from 0.03 A to 40 A across a wide frequency range up to 2000 Hz, providing early warning and alarm signals via two change-over relay outputs. Its digital LCD display and adjustable response time (0.02–20 s) make it an essential component for enhancing electrical safety and preventing costly downtime.

Advantages

AC/DC sensitive measuring principle (Type B) ensures reliable detection of smooth DC residual currents, pulsating DC, and AC faults. The wide auxiliary voltage range of 24–240 V AC/DC allows flexible integration into various control circuits. Two independently adjustable thresholds (warning and alarm) enable staged response strategies. The digital display provides clear, real-time residual current values and status indication. DIN rail mounting and screw terminals simplify installation and maintenance.

Suitable for

• Monitoring residual currents in industrial machinery and installations
• Protecting against insulation faults in DC charging stations and photovoltaic systems
• Enhancing safety in data centers and critical power distribution
• Integrating with external current transformers (e.g., 3UL23 series) for high-current applications

Key specifications

• Measuring principle: AC/DC sensitive (Type B)
• Number of channels: 1
• Rated supply voltage: 24–240 V AC/DC
• Measuring range: 0.03–40 A
• Response time: adjustable 0.02–20 s
• Output: 2 change-over contacts (5 A at 250 V AC)
• Mounting: DIN rail 35 mm
• Degree of protection: IP20 (terminals), IP40 (front)
• Operating temperature: -25 to +60 °C

Recommendations

For optimal performance, pair this relay with a SIEMENS 3UL23 series external current transformer matching your load current. Ensure proper shielding and grounding of signal cables to minimize electromagnetic interference. Configure the warning threshold below the alarm threshold to allow preventive action before critical faults occur.