C denotes that the neutral conductor and the protective earthing conductor are one and the same conductor. This means that four conductors need to be routed for a three-phase consumer. The different earthing types are illustrated with the diagrams that now follow:.
Labels: Earthing. Newer Post Older Post Home. You May Also Like:. E14 — TN-S system. IT system: Protection technique: Interconnection and earthing of exposed conductive parts Indication of the first fault by an insulation monitoring device IMD Interruption for the second fault using overcurrent protection circuit-breakers or fuses Operating technique: Monitoring of the first insulation fault Mandatory location and clearing of the fault Interruption for two simultaneous insulation faults.
E15 — IT system. Add a comment. This page was last edited on 20 December , at Navigation Special pages Random page Search Log in. The most common arrangement is a two core cable Live and Neutral with a lead outer sheath Earth.
The lead is covered with a spiral steel band for added protection. This has several advantages, the main one being that for underground supplies, the outer metal sheath is in direct contact with the ground for the whole length of the cable.
This ensures the earth connection is at the same potential as the real earth. One disadvantage is that over time, the outer metal sheath corrodes, until it is no longer an effective conductor. When this happens, the only solution is to replace the cable.
You will normally then get a TNCS supply, as the lead cable is not used any more.
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