Which earthing arrangement uses a PEN conductor up to a point, then splits into PE and N?

Which earthing arrangement uses a PEN conductor up to a point, then splits into PE and N?

• A. TT
• B. TN-S
• C. TN-C-S
• D. IT

Answer: (C)

TN-C-S is the arrangement that uses a single PEN conductor up to a point and then splits into separate protective earth and neutral conductors. In this setup, the supply provides a combined earth/neutral path (PEN) until the installation boundary, where it is separated into PE and N for the consumer’s circuits. This provides a common return path and an earth reference coming into the building, while keeping the final wiring with distinct earth and neutral. The other systems differ in whether PE and N are separate from the start (TN-S), whether a PEN is used throughout (TN-C), or whether the supply is isolated with no earth reference (IT).

TN-C-S is the arrangement that uses a single PEN conductor up to a point and then splits into separate protective earth and neutral conductors. In this setup, the supply provides a combined earth/neutral path (PEN) until the installation boundary, where it is separated into PE and N for the consumer’s circuits. This provides a common return path and an earth reference coming into the building, while keeping the final wiring with distinct earth and neutral. The other systems differ in whether PE and N are separate from the start (TN-S), whether a PEN is used throughout (TN-C), or whether the supply is isolated with no earth reference (IT).