What is the 18th Edition?

Glossary · Regulations and registration

How the 18th Edition works

BS 7671 is the national standard for electrical installations in the UK, and the 18th Edition is its current edition. The IET co-publishes it with the British Standards Institution (BSI) and leads the committee, JPEL/64, that keeps it up to date.^{[1]Institution of Engineering and Technology (IET), Stay compliant: ensure you are up to date with BS 7671} It is often called the IET Wiring Regulations or, among electricians, the wiring regs.

The IET says it is the UK national standard for all new low voltage electrical installations, for additions and alterations to existing installations, and for periodic inspection and testing of existing installations.^{[2]Institution of Engineering and Technology (IET), IET and BSI officially publish Amendment 4 (2026) to BS 7671:2018} That is why it matters to homeowners: it is the yardstick for a new circuit, an electrical installation certificate and an EICR.

For rented homes, the government guidance says landlords must ensure the electrical safety standards in the 18th Edition, published as British Standard 7671, are met.^{[4]Ministry of Housing, Communities and Local Government, Electrical safety standards in the private and social rented sectors: guidance}

Amendments and the 2026 changeover

The 18th Edition is not rewritten each time. It is changed by numbered amendments. The IET timeline is:^{[3]Institution of Engineering and Technology (IET), Mythbuster #13: The four amendments to the rumour-mill (Wiring Matters, April 2026)}

The IET says Amendment 4 is the current edition of the standard.^{[1]Institution of Engineering and Technology (IET), Stay compliant: ensure you are up to date with BS 7671} Its main changes are new sections on Power over Ethernet and on functional earthing for information and communication technology equipment, and a major revision of the section on medical locations.^{[1]Institution of Engineering and Technology (IET), Stay compliant: ensure you are up to date with BS 7671} Most of that is specialist. For an EICR, the IET reports that the amendment changed the classification code wording so that C3 and FI no longer make a report unsatisfactory, which our page on EICR observation codes explains.^{[5]Institution of Engineering and Technology (IET), Implications of BS 7671:2018+A4:2026 on an EICRs (Wiring Matters, July 2026)}

Example

Fatima’s house in Pudsey was wired in the 1990s, well before the 18th Edition. She is worried it will fail an inspection for that reason. It will not. The IET is clear that an installation that complies with an earlier edition is not necessarily unsafe, even if it is not to the current level of safety. The inspector judges its actual condition.^{[3]Institution of Engineering and Technology (IET), Mythbuster #13: The four amendments to the rumour-mill (Wiring Matters, April 2026)} If she later has a new circuit installed, that new work is designed and tested to the edition in force at the time.^{[2]Institution of Engineering and Technology (IET), IET and BSI officially publish Amendment 4 (2026) to BS 7671:2018}

What people get wrong

The commonest mistake is believing that old wiring is illegal or must be upgraded the moment a new edition appears. Standards are not retrospective. Upgrading to the latest edition may improve safety and a client may agree to it, but it is not a requirement.

The IET makes one exception. Where new equipment is installed that is not compatible with an existing installation, the existing installation may have to change.^{[3]Institution of Engineering and Technology (IET), Mythbuster #13: The four amendments to the rumour-mill (Wiring Matters, April 2026)} Our page on when to replace a consumer unit covers a related question.

The bottom line

The 18th Edition is BS 7671, the standard every registered electrician works to. It applies to new work, alterations and inspections, and Amendment 4 of 2026 is now the version in use. It does not force you to rewire a house that was built to an earlier edition. If you are unsure whether work you have had done meets the standard, an EICR will tell you the condition of the installation.