In TN-S earthing, what is true?

• A. It uses a separate protective earth conductor from the source.
• B. It uses a PEN conductor from source to load.
• C. It uses a local earth electrode.
• D. It has no protective earth.

Answer: (A)

In TN-S earthing, the protective earth path is a separate conductor that runs from the source to the load, distinct from the neutral throughout the circuit. The neutral and earth are not shared along the way (no PEN conductor), and they are only bonded together at the source of supply. This dedicated earth path provides a low-impedance route for fault currents to return, so protective devices trip quickly and exposed metal parts stay at earth potential. A local earth electrode at the installation might be present for reference, but it doesn’t define TN-S; the defining feature is the separate protective earth conductor from source to load.