How do I correctly wire current transformers (CTs) to the Schneider Electric SC150 Switch Control Unit?

[SanVivian]

To properly connect current transformers (CTs) to your Schneider Electric SC150 Switch Control Unit, follow these steps for a safe and functional setup:

1. Wiring Orientation: When attaching the CTs, ensure the "HAUT/TOP" marking faces upwards and the wire exit points downwards. This alignment is critical for correct operation.
2. Shielding Re-insertion: Before grounding, re-insert the shielding of each medium-voltage (MV) cable inside its corresponding CT. This is a vital safety measure.
3. Grounding Connection: Connect the CT secondary's blue wire (S2), which has an internal connection to the blue wire with a round terminal, to the same frame ground as the cubicle. This ensures proper grounding.
4. Safety First: Always use grounded external CTs to prevent electrical hazards. Prior to any work on or near the MV cable, ensure all power on the MV network is switched off.
5. CT Specifications: Ensure your current sensors are designed with a 1 A or 5 A secondary and a security factor that limits current to 100 A secondary for 1 second. Adhere to all specified current sensor standards.
6. Tools and Techniques: Use the right tools, such as an appropriate screwdriver and crimped end-pieces, to cable the connectors. Prepare the wires correctly before connecting them to the connectors, following the recommendations in the Schneider Electric SC150 Switch Control Unit installation guide. Following these guidelines will help ensure a secure and effective connection of your CTs to the Schneider Electric SC150 Switch Control Unit.