Explanation of Outer CT (G/F) and Communication Options in LS MCCBs

Explanation of Outer CT (G/F) and Communication Options in LS MCCBs

Outer CT (G/F) Option

  • The “Outer CT (G/F)” option refers to earth leakage protection, not ground fault protection.
    While it may look similar, it's specifically designed to detect earth leakage current through an external CT connected to the OCR.

  • “Outer CT” means that the unit is compatible with external CTs (such as type Z) for external current measurement or protection purposes.

  • NCT (Neutral CT) cannot be used. Only ZCT and other external CTs are supported.

Communication Options

  • “X” means no communication function is included.

  • “O” means the breaker supports communication, such as Modbus, via the appropriate communication module.