The residual current monitor RCM475LY is designed for fault and residual current monitoring in earthed power supply systems (TN and TT systems) where an alarm is to be activated in the event of a fault, but disconnection must be prevented. In addition, the device can be used to monitor single conductors, such as PE conductors, N-PE connections and PE-PAS connections.

Since the values are measured with measuring current transformers, the device is nearly independent of the load current and the nominal voltage of the system.

• Internal measuring current transformer ø 18 mm
• Response values, adjustable
• Response delay, adjustable 0…10 s
• Alarm relay with two potential-free changeover contacts
• N / O or N / C operation, selectable
• Fault memory behaviour, selectable
• Combined test / reset button

• Residual current monitoring in earthed two, three or four conductor systems (TN and TT systems)
• Current monitoring of single conductors de-energised under normal conditions
• Socket-outlet circuits for devices which are operated unattended for a long time and which may not fail
• Alarm systems, safety devices
• Air conditioning systems, EDP systems
• Cooling equipment with valuable frozen goods
• Canteen kitchens
• Monitoring of earthed power supplies for stray currents, impact on N conductors