Differential protection relay RH99M type A

Differential protection relay type RH99M, designed to detect residual ground currents in electrical installations of 220–240 V AC 50/60 Hz. It is mounted on DIN rail and is compatible with open and closed toroidal type A transformers of the TOA range. Its operation is based on the internal residual current measurement with detection range of 80 to 100 %.

Technical characteristics

• Implementation: Relay protection
• Mounting bracket: Rail DIN
• Type of ground leak protection: Type A
• Adjustment type: Configurable by feeder
• Leak current to ground: 0.03...30 A
• Differential shot timing adjustment type: Instant for 0.03 A; 9 configurable settings from 0 to 4.5 s for 0.03...30 A
• Range compatibility: Toroidal toroidal closed type A and open type TOA A, TOA L
• Power voltage assigned: 220...240 V AC 50/60 Hz 55...110 %
• Power consumption: 4 VA
• Network voltage: 1000 V - AC at 50/60 Hz - cable type: maximum; 1000 V - AC at 400 Hz - cable type: maximum
• Ground connection system: TN-S, TT, IT
• Voltage peak resistance: 8 kV
• Reset: Manual
• Test function: Remote and local test
• Monitoring: Electronic components - cable type: continuous; Power supply - cable type: continuous; Relay/sensor link - cable type: continuous
• Internal ground leakage current measurement, range: 80...100 %
• Inviolability of adjustments: Protected by sealable cover
• Connections: Auxiliary power supply, defect contacts, test and reset, toroidal, tension presence with screw terminals and flexible/rigid wiring ranges
• Peeled cable length: 7 mm (feed), 8 mm (defect), 5 mm (test/reset), 5 mm (toroidal), 8 mm (voltage)
• Tightening torque: 0,6 N·m (feed, voltage), 0,6 N·m (defect), 0,25 N·m (test/reset, toroidal)
• Steps of 9 mm: 6
• Dimensions: 54 mm (width), 81 mm (high), 74 mm (depth)
• Weight: 0.3 kg
• Degree of IP protection: IP40 (front), IP30 (side), IP20 (terminals)
• Level of protection IK: IK07
• Overvoltage category: IV
• Electrical shock protection class: Class II
• Electromagnetic compatibility: Conducted and irradiated emissions (Class B), immunity to RF, DSU, overvoltage, interference
• Relative humidity: 95 % at 55 °C
• Degree of contamination: 3
• Operating ambient temperature: -35...70 °C
• Storage ambient temperature: -55...85 °C
• Sustainable supply status: Product Green Premium
• EU RoHS Directive: As per
• No mercury: Yes
• No PVC: Yes
• WEEE: Must be recycled according to specific system in the EU