SS 551:2022 (Redline)

Code of practice for earthing


This standard provides guidance on meeting the requirements for the earthing of electrical installations, including:

a) protective earthing of low voltage installations to SS 638;
b) the interface between LV and HV substations within buildings; and
c) protective earthing and changeover switch arrangements for generators supplying low voltage installations.

The earthing of a system or installation is generally provided for reasons of safety.

This standard applies only to land-based installations in and around buildings. It does not apply to:

1) ships, aircraft or offshore installations;
2) earthing of medical equipment;
3) special problems encountered with solid state electronic components;
4) equipment sensitive to static electricity;
5) requirements for functional earthing;
6) earthing of overhead lines between electrical installations; or
7) the internal earthing of equipment.


Redline version of the document shows changes from the previous edition marked in colour. With the Redline you can quickly spot changed sections and tell specifically what has been changed from the previous edition, saving time and avoiding confusion.


Status Current
Edition 2022 (Redline)
No. of Pages 161
ICS Classification 13.260 Protection against electric shock. Live working
29.240.01 Power transmission and distribution networks in general
Committee Electrical and Electronic Standards Committee
Available for Purchase Global
Adoption -