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Power System Earthing Practice (Guide)


Note: File may be downloaded after completion of your purchase.

This guide applies the risk method to practical earthing systems. It is complimentary to the 2006 Risk Based Earthing System Design (Guide), which is about risk evaluation.

This guide was written to comply with the New Zealand Electricity Act 1992 and the New Zealand Electricity Regulations 1997 and their amendments as well as the Electricity (Hazards from Trees) Regulations 2003. The Electricity Regulations are currently under review and will be replaced by the Electricity Safety Regulations, which, with the amended Act, will have content intended to safeguard members of the public and their property.

The electricity supply industry has both general and specific safety responsibilities placed on it by the Health and Safety in Employment Act 1992, the Electricity Act 1992 and Regulations made under those Acts.

The industry recognises those legal responsibilities and has therefore developed the EEA New Zealand Electricity Networks Guide to Power System Earthing Practice to provide industry-wide safe earthing guidelines.

The guide is intended to provide guidance to asset owners on the practicable steps that employers must take to safeguard their own employees, contractors' employees, and members of the public in the vicinity of work places as required by the Health and Safety in Employment Act 1992.

The purpose of this guide is to give guidance and advice on safe earthing practices for high voltage a.c. power systems adequate to meet the requirements of electricity safety legislation. This document provides guidance on power system earthing in general as set out in sections 1 to 4, and also includes specific sections for:

  • High voltage (HV) a.c. station (section 5);
  • Distribution centres, equipment, and lines up to 22 kV

    (section 6);

  • High voltage a.c. transmission/sub-transmission lines of

    33 kV and over (section 7).

This guide does not apply to:

  • Aspects of low voltage (LV) earthing on consumers'

    installations, which are covered by the Wiring Rules (AS/NZS


  • Systems not operated at a normal frequency of 50 Hz;
  • Temporary earthing;
  • Specific requirements related to Single Wire Earth Return

    (SWER) systems, including requirements associated with steady

    state EPR issues.

Comments for the revision of this guide are welcomed and should be forwarded to:
EEA Guide to Power System Earthing Practice - Convenor
PO Box 5324
Wellington 6145
New Zealand

August 2009

$350.00 - $400.00
$0.00 - $250.00
Members' Price

All prices exclude GST and are represented in New Zealand Dollars

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