The DOLD RN 5884.12 Series Type B Residual Current Monitor (German: Differenzstromwächter Typ B / English: Type B Residual Current Monitor - RCM) represents the next generation of intelligent electrical protection instruments belonging to the prestigious VARIMETER RCM family, researched and manufactured by E. DOLD & SÖHNE GmbH & Co. KG in Germany. In modern power infrastructure and industrial automation cells, the widespread integration of solid-state semiconductor converters—such as variable frequency drives (VFDs), multi-axis servo controllers, electric vehicle (EV) DC fast chargers, solar photovoltaic (PV) inverters, and battery energy storage systems (BESS)—has fundamentally transformed the waveform characteristics of ground leakage currents. When insulation breakdown occurs within these systems, leakage currents deviate significantly from standard 50/60Hz AC waveforms, exhibiting smooth DC, pulsating DC, and high-frequency AC components reaching frequencies up to 100 kHz.

Conventional Type A and Type AC residual current protective devices are completely blind to smooth DC residual currents. Furthermore, smooth DC leakage saturates the magnetic cores of Type A sensing transformers, blinding them and disabling their ability to trip during secondary ground faults, thereby creating grave electric shock and fire hazards. The DOLD RN 5884.12 series is engineered to eliminate these vulnerabilities in strict accordance with international standards IEC/EN 62020 and IEC 60947-2 Annex M. Operating on an all-current sensitive (allstromsensitiv) differential measuring principle, it interfaces with external DOLD Type B measuring current transformers (ND 5016, ND 5017, ND 5018, ND 5019) to deliver continuous, predictive insulation surveillance well before leakage escalates into catastrophic fault levels, eliminating unexpected plant shutdowns.

The DOLD RN 5884.12 series features an extended measuring range spanning from 30 mA up to 5000 mA (0.03 A to 5 A), making it ideal for large-scale installations with higher inherent operational capacitance leakage. An adjustable response time delay from 0 to 10 seconds (Tv = 0 - 10s) effectively suppresses transient nuisance tripping caused by capacitive inrush currents during equipment startup.

This comprehensive entry consolidates eleven specialized models across two wide auxiliary voltage ranges (AC/DC 24-100V and AC/DC 80-240V):
1. Standard RN 5884.12 Models:
- RN5884.12 AC/DC24-100V 0-10S & RN5884.12 AC/DC80-240V 0-10S: Standard single-channel monitoring models equipped with 2 independent changeover contacts (2 C/O) configured for segregated Prewarning and Alarm functions.
2. Variant RN 5884.12/001:
- RN5884.12/001 AC/DC80-240V 0-10S: Optimized filter frequency variant engineered for severe electromagnetic interference (EMI) environments near heavy-duty frequency inverters.
3. Variant RN 5884.12/002:
- RN5884.12/002 AC/DC24-100V 0-10S & RN5884.12/002 AC/DC80-240V 0-10S: Dual-channel measuring models supporting two independent current transformers (CT1 and CT2) within a single housing, providing segregated alarm contacts for each channel and cutting hardware costs and cabinet space by 50%.
4. Variant RN 5884.12/003:
- RN5884.12/003 AC/DC24-100V 0-10S & RN5884.12/003 AC/DC80-240V 0-10S: Integrated with an RS-485 Modbus RTU serial communication interface, streaming real-time residual current values, fault logs, and remote parameter configuration directly to master SCADA/PLC platforms.
5. Variant RN 5884.12/004:
- RN5884.12/004 AC/DC24-100V 0-10S & RN5884.12/004 AC/DC80-240V 0-10S: Dual-channel measuring variant with specialized contact telemetry assignments for complex industrial feeder configurations.
6. Variant RN 5884.12/005:
- RN5884.12/005 AC/DC24-100V 0-10S & RN5884.12/005 AC/DC80-240V 0-10S: Multi-feature digital variant combining dual-channel monitoring with Modbus RTU telemetry, tailored for intelligent data centers and EV charging hubs.

Packaged in a compact 52.5 mm wide RN enclosure for 35mm DIN-rail mounting, the device features a front-panel multi-LED bar graph indicating real-time residual current percentages alongside integrated Test and Reset pushbuttons. Certified under international standards IEC/EN 62020 and DIN VDE 0100-482, the DOLD RN 5884.12 provides dependable, all-current residual safety protection across modern automated industrial facilities worldwide.

• Manufacturer: DOLD (E. DOLD & SÖHNE GmbH & Co. KG)
• Country of Origin: Germany
• Product Series: VARIMETER RCM - RN 5884
• Contact Configuration Code: .12 (2 Changeover contacts - 2 C/O contacts)
• Measuring Classification: Type B Residual Current Monitor (All-current sensitive: AC, pulsating DC, smooth DC up to 100 kHz)
• Covered Product Part Numbers:
  - RN5884.12 AC/DC24-100V 0-10S (Standard 1-channel, 24-100V supply)
  - RN5884.12 AC/DC80-240V 0-10S (Standard 1-channel, 80-240V supply)
  - RN5884.12/001 AC/DC80-240V 0-10S (Optimized noise filter variant, 80-240V supply)
  - RN5884.12/002 AC/DC24-100V 0-10S (2-channel measuring model CT1/CT2, 24-100V supply)
  - RN5884.12/002 AC/DC80-240V 0-10S (2-channel measuring model CT1/CT2, 80-240V supply)
  - RN5884.12/003 AC/DC24-100V 0-10S (Modbus RTU RS-485 interface, 24-100V supply)
  - RN5884.12/003 AC/DC80-240V 0-10S (Modbus RTU RS-485 interface, 80-240V supply)
  - RN5884.12/004 AC/DC24-100V 0-10S (Extended 2-channel model, 24-100V supply)
  - RN5884.12/004 AC/DC80-240V 0-10S (Extended 2-channel model, 80-240V supply)
  - RN5884.12/005 AC/DC24-100V 0-10S (Multi-function Modbus RTU model, 24-100V supply)
  - RN5884.12/005 AC/DC80-240V 0-10S (Multi-function Modbus RTU model, 80-240V supply)
• Measuring Residual Current Range: 30 ... 5000 mA (0.03 A to 5 A infinitely adjustable via potentiometer)
• Frequency Response: DC to 100 kHz
• Auxiliary Operating Supply Voltage (UH):
  - AC/DC 24 ... 100 V range (Tolerance 0.85 ... 1.15 UH)
  - AC/DC 80 ... 240 V range (Tolerance 0.85 ... 1.15 UH, 50/60 Hz or DC)
• Compatible External Current Transformers: DOLD Type B measuring current transformers ND 5016, ND 5017, ND 5018, ND 5019
• Measuring Channels: 1 Channel or 2 independent channels (model dependent on /002, /004, /005)
• Digital Communication (Optional on /003, /005): Modbus RTU via RS-485 serial port
• Response Time Delay (Tv): Infinitely adjustable from 0 to 10 seconds (Tv = 0 ... 10s)
• Output Contact Arrangement: 2 Changeover contacts (2 C/O - 2 x 1 Wechsler)
• Contact Breaking Capacity: AC-15: 3A / AC 230V; DC-13: 2A / DC 24V (according to IEC/EN 60947-5-1)
• Continuous Thermal Current (Ith): Max. 5A
• Diagnostic Display & Controls: Front multi-LED residual current bar graph, error LEDs, Test and Reset pushbuttons
• Enclosure Dimensions (W x H x D): 52.5 x 90 x 71 mm (Standard RN housing)
• Mounting Profile: Quick snap-on mounting on standard 35 mm DIN-rail (IEC/EN 60715)
• Wiring Terminals: Vibration-proof box clamp screw terminals
• Protection Rating: Housing IP40, Terminals IP20 (according to IEC/EN 60529)
• Ambient Operating Temperature: -20°C to +60°C
• Compliant Safety Standards: IEC/EN 62020, IEC 60947-2 Annex M, DIN VDE 0100-482, CE
• Common Industrial Deployments: Variable speed drives, EV charging infrastructure, solar PV systems, BESS battery rooms, data centers, and automated manufacturing lines