In addition to the TN power grids, there are also TT and IT power grids.
TN-C
| DN | HCB | CI |-∩∩∩-|---|-----|---o------- L1 |-∩∩∩-|---|-----|---|------- L2 |-∩∩∩-|---|-----|---|------- L3 |-----|---|--o--|---|-o-o--- PEN | TS | | | | ⊥ ⏚ ⏚ [ Device ]
Applicable protection mechanism: MCB
TN-S
| DN | HCB | CI |-∩∩∩-|---|-----|---o------- L1 |-∩∩∩-|---|-----|---|------- L2 |-∩∩∩-|---|-----|---|------- L3 |-----|---|-----|---|-o----- N |-----|---|--o--|---|-|-o--- PE | TS | | | | ⊥ ⏚ ⏚ [ Device ]
Applicable protection mechanism: MCB and RCD
TN-C-S
| DN | HCB | CI |-∩∩∩-|---|-----|---o------- L1 |-∩∩∩-|---|-----|---|------- L2 |-∩∩∩-|---|-----|---|------- L3 |-----|---|--o--|---|-o----- N | TS | | |--|---|-|-o--- PE | | | | ⊥ ⏚ ⏚ [ Device ]
A combination of TN-C (VN) and TN-S (VA).
Abbreviations
- HCB … House Connection Box
- TS … Transformer Station
- CI … Consumer Installation
- DN … Distribution Network