Installation of vertical earth (stake) electrodes

This information bulletin provides information to Northern Territory licensed electrical workers and contractors to the requirements of Australian Standards concerning the installation of earth electrodes, as per AS/NZS 3000:2018 Wiring Rules.

NOTE: Clauses and Tables mentioned below refer to: AS/NZS 3000:2018 Wiring Rules.

Protection against mechanical damage

Earth electrodes, Main Earth conductors and associated connections shall be adequately protected against damage from external influences to which they may be exposed. E.g. being kicked, tripped over, stepped on or hit with vehicles, power tools, garden implements etc which may cause the main earth to become detached from the electrode. Clauses 1.5.14, 5.5.1.2(c) and 5.5.5.2

Depth of installation

Vertical-type earth electrodes must be driven to a minimum depth of 1.2 meters in Australia. Clause 5.3.6.3

Location of electrode installation

Earth electrodes shall be installed in a location that satisfies the following conditions:

1. The electrode must maintain effective contact with moist soil that is not subject to excessive drying out.
2. The electrode must be separated from conductive enclosures of other buried services, such as water, gas, telecommunications and flammable liquid, in order to reduce possible electrolytic action affecting the electrode or the other service.  NOTE: Separation distances are specified in Table 3.7
3. The main earthing conductor connection to an electrode must be accessible. Clause 5.3.6.4 and Table 3.7.

Identification

The location of the earth electrode shall be identified at the main switchboard. Clause 5.3.6.4

Labelling

Clause 5.5.1.3 requires the main earthing conductor shall have a permanent label attached at the connection to the earth electrode with a legible warning against disconnection:

WARNING: ‘MAIN ELECTRICAL EARTHING CONDUCTOR – DO NOT DISCONNECT’