scope:

PURPOSE AND SCOPE

A correctly designed earthing system is inherently safe under both steady state and transient fault conditions and therefore should present no danger to persons present within its vicinity. If though an earthing system is defective because of theft of part of that system or depleted because of defective or damaged connections, then work should be undertaken in a safe manner to restore the earthing system back to normal.

In order to do the corrective work necessary to restore the earthing system back to normal and because it is not practical to de-energise the network to do so, temporary connections will need to be applied safely and as appropriate prior to the commencement of any permanent repair work.

This Document provides guidance on methods of safely applying these temporary connections and is intended for use within National Grid substations and cable sealing end compounds. This document should also be read in conjunction with NSI 24.

Guidance on how to determine whether there is a break in earth continuity from a overhead line terminal tower to its donor substation and on how to temporarily re-establish this bond safely prior to its permanent repair is detailed within National Grid documents TGN(E)204 and TGN(E)215