British Standards

BS 7430 Code of practice for protective earthing of electrical installations

BS 7430:2011+A1:2015
Code of practice for protective earthing of electrical installations

Publication Date: 31 December 2011

Amended By
Corrigendum, May 2012.
Amendment, August 2015. Amends and replaces BS 7430:2011.

BSI Online link


This standard is an amendment to BS 7430:2011 Code of practice for protective earthing of electrical installations. It provides recommendations and guidance on meeting the requirements for earthing land-based electrical installations in and around buildings in the UK.

Since BS 7430 was last revised in 2011 a number of queries, errors and inaccuracies were brought to BSI’s attention by users. This amendment addresses these issues and provides clarification on a number of points in the standard in order to eliminate any ambiguity.

BS 7430 has significant safety implications as effective earthing safeguards people from the risk of electric shock. To design, specify, inspect and periodically test and maintain earthing systems without endangering those who come into contact with them, users need to follow the guidelines and recommendations outlined in the amended 2015 version of the standard.

What does the standard cover?

BS 7430 covers earthing system design parameters for structures, electrical equipment and systems.

It also defines selection parameters for the earthing arrangements and makes clear the need for careful consideration of various site conditions such as soil composition and resistivity. Earthing is generally provided for reasons of safety as it protects people from the risk of electric hock.

How has the standard been amended?

It includes a number of editorial changes which clarify the meaning of the text and correct values and symbols. It also includes some technical changes to correct and clarify formulae and equations.