Remote areas use TT, where the cost of an additional PE conductor outweighs that of a local earth connection.
Installations on a construction site, a farm, or a swimming pool may be improper unless additional measures, like installing extra earth electrode is adopted.For LV system earth, TT earthing helps in earthing such devices when low voltage arises in the system.
All metallic enclosures and extraneous parts are at equipotential.
Protection from lightning because of low fault current.
Protection from earth fault current because of low resistance pat
Advantages of TT Earthing:
-Simplicity (very few calculations when installing)
-Extension that does not necessitate the calculation of lengths
-Fault currents are low
-There is very minimal upkeep
-Operation with a low projected current source
-Ease of entry for conductors, smooth edges
-It is economical, safe and high graded in use
-Good withstanding capacity against harmonics supplied in the system
But you need to look out for two problems One maximum short circuit fault current (you may need a fuse as a breaker may fry, unlikely but you need to calculate) and the second is the neural developing a voltage if the ground becomes dry. Remember your earth rod or rods and neutral link. To achieve a safe installation you may also need to fit both fuse and RCD according to the UK electrical regulations (BS 7671), "Regulation 411.5.2 "One or More PROTECTIVE DEVICE.
411.5. 2 One or more of the following types of protective device shall be used, the former being preferred: (i) An RCD (ii) An overcurrent protective device. NOTE 1: An appropriate overcurrent protective device may be used for fault protection provided a suitably low value of Zs is permanently and reliably assured.
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