What is Standard BS7430

BS7430 2015 is the latest amendment to the code of practice for protective earthing of electrical installations.

BS7430 Overview

This standard is an amendment to BS7430 2011 the 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 latest 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.

Who is the standard BS7430 for?

The standard is relevant in the following sectors: transport, aerospace, auto, railway, built environment, education and training, finance, healthcare, ICT, industrial (engineering services, electrical equipment, chemical, materials, food and agriculture, mechanical equipment, R&D, testing, textiles), services, oil/gas/energy.

It is of particular relevance to:

  • Electricians and electrical engineers.
  • Engineering service providers.
  • Designers, specifiers, installers and maintainers of earthing and lightning protection equipment.
  • Built environment specialists (architectural and surveying services, building contractors, construction products providers).
  • Librarians at colleges and technical institutes.
  • Councils and housing associations.
  • ICT service providers.
  • Electrical/electronic appliance manufacturers.

What do the standard BS7430 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 shock.

How has the EN BS 7430 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.

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