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1. Supply Systems 
2. Acronym T  Terre (French for soil or earth)
N  Neutral
C  Combined
S - Seperated 
3. TN-S Terre Neutral  Separate
The supply authority provide a separate neutral and earthing conductor from the supply transformer 
4. TN-S 
5. TN-S 
6. TN-C-S (PME) Terre Neutral  Combined  Separate
Protective Multiple Earth
The neutral and earth conductor are supplied as a single conductor until the main cutout in the consumers property.
Uses a PEN conductor (Protective Earthed Neutral)
Common in urban areas 
7. TN-C-S (PME) 
8. TN-C-S (PME) 
9. TT Common in rural areas
Due to high impedances to earth, an RCD is employed as additional protection
 
10. TT Terre Terre 
Supply authority supply only a live and a neutral conductor, the consumer has the responsibility for providing their own earth connection
Often achieved with the use of earth electrode rods
 
11. TT 
12. TT