Connecting protective earthing to relay - Arc protection - Auto synchronization - Bay control and measurement - Merging unit - Transformer protection - 2 winding - Feeder protection - Voltage regulation - Capacitor bank protection - Petersen Coil control - Grid automation - Busbar differential protection (high impedance) - Back-up protection - Motor protection - Busbar protection (voltage and frequency) - Transformer protection - 3 winding - Interconnection protection - Generator protection - Power management/Load shedding - Installation Manual - REX640 Protection and control - Relion Protection and Control - PCL4 - IEC - ANSI - 16.02.2023

REX640 Installation Manual

Connect the protection relay to earth using a 6 mm2 (AWG 10) flat braided copper cable. Use an earth lead of maximum 1.5 m (4.9 ft). Extra length is required for door mounting.

Note: A 16 mm2 (AWG 6) flat braided copper cable is recommended for more demanding EMI environments, such as installations where the relay is mounted inside a gas insulated switchgear.
  1. Using a TX30 screwdriver, loosen the protective earth screw to connect a separate earth protection lead.
    Figure 1. Location of the protective earth pin
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    CAUTION: Each protection relay must have its own earth lead connected to the earth circuit connector.
  2. Connect the earth lead to the earth bar.
  3. Thread the copper cable on the protective earth.
  4. Tighten the protective earth screw to 6 Nm ±5% (4.4254 ft-lb ±5%).
  5. Support the earth lead so that it cannot break or weaken.

    Observe the mechanical, chemical or electrochemical conditions.