In a TT earthing system, where is the earth electrode located?

• A. At the consumer's premises, with a local earth electrode.
• B. At the transformer substation
• C. Shared with neighboring buildings
• D. Not required

Answer: (A)

In a TT earthing system, the protective earth path for a consumer’s installation is provided by an earth electrode installed at the consumer’s premises. The supply transformer is earthed separately at the substation, and there is no direct earth connection between the installation’s earth and the transformer earth. If a fault occurs, the current returns through the soil to the substation earth, so the local electrode at the premises is essential to establish the earth reference for safety. That’s why the earth electrode must be located at the consumer’s premises.

Putting the earth electrode at the transformer substation wouldn’t serve the installation’s protective path in TT, sharing an earth with neighboring buildings would create variable and unsafe fault paths, and saying it’s not required ignores the fundamental need for a local earth electrode in TT systems.