DOLD RN5884 Residual Current Monitor

14-04-2026

The RN5884 residual current monitor from the VARIMETER RCM series is designed to provide early warning of insulation faults in earthed AC/DC systems.

As an AC/DC-sensitive Type B monitor, it detects residual currents containing AC, pulsating DC and smooth DC components via an external current transformer. By identifying developing faults early, the RN5884 helps reduce unplanned downtime and supports preventive fire and system protection.

RN5884 residual current monitor for earthed AC/DC systems

Suitable for use in modern AC/DC networks, the RN5884 monitors residual currents up to 2 kHz and offers an adjustable measuring range from 30 mA to 5 A. Set parameters and response thresholds easily from the front of the unit using the operating buttons, while the display provides a clear visual indication of the measured residual current. When the residual current exceeds the defined threshold, output relay K1 or K2 signals the condition.

Single-channel and two-channel versions

Both the single-channel and two-channel versions are equipped with two output relays.

In the single-channel version, K1 provides alarm signalling and K2 pre-alarm signalling. In the two-channel version, K1 serves CT1 and K2 serves CT2, giving each measuring channel a dedicated alarm output The RN5884 supports up to two current transformers and an optional Modbus RTU interface, allowing flexible integration into modern monitoring systems. For detailed technical information, view the RN5884 datasheet.

Typical applications:

Where early fault detection and continuous operation are critical, the RN5884 provides reliable monitoring for applications including:

• Data centres
• EV charging infrastructure
• Building automation systems
• HVAC plant rooms and chiller systems
• Industrial automation and process plants
• UPS systems and critical power supplies
• Battery energy storage systems (BESS)

Key benefits at a Glance:

• Early fault detection to help reduce unplanned downtime
• Preventive fire and system protection
• Improved system availability through continuous monitoring
• Suitable for use in AC/DC networks
• Supports connection of up to two current transformers
• Optional Modbus RTU Interface for straightforward parameterisation, monitoring and diagnostics
• Compact 52.5 mm housing for space-saving panel installation
• Adjustable measuring range from 30 mA to 5 A

Supporting targeted maintenance:

Additional features such as wire-break detection, an integrated test function and adjustable switching delays help maintenance teams respond quickly and plan interventions more effectively. This supports targeted, cost-effective maintenance and helps keep critical installations in service.

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