Means of disconnection of the earthing conductor

There can be a problem if a convenient and suitable means of disconnection has not been provided for the earthing conductor of an installation for test purposes.

Solution

A means of disconnection of the earthing conductor must be provided at or near the Main Earthing Terminal (MET) of an installation to facilitate measurement of the resistance of the earthing arrangements (Regulation 542.4.2 refers).

For larger installations, the requirements will often be met by providing a bolted link. For smaller, domestic installations, the earthing conductor will normally connect directly to the earthing bar in the consumer unit and disconnection will be effected by unscrewing and drawing back the earthing conductor.

Regulation 542.4.2

To facilitate measurement of the resistance of the earthing arrangements, means shall be provided in an accessible position for disconnecting the earth conductor. Such means may conveniently be combined with the main earthing terminal or bar. Any joint shall be capable of disconnection only by means of a tool.

This article is extracted from Snags and Solutions Part 3 published by the: NICEIC Group