5.2.4 - TN-C-S system

In this system, the installation is TN-S, with separate neutral and protective conductors. The supply, however, uses a common conductor for both the neutral and the earth. This combined earth and neutral system is sometimes called the 'protective and neutral conductor' (PEN) or the 'combined neutral and earth' conductor (CNE). The system, which is shown diagrammatically in {Fig 5.6}, is most usually called the protective multiple earth (PME) system, which will be considered in greater detail in {5.6}.

Fig 5.6 - TN-C-S earthing system - protective multiple earthing