18th Edition, Requirements for Electrical Installations (Orange Book)
BS 7671:2018+A4:2026 — IET Wiring Regulations 18th Edition
Requirements for Electrical Installations (The Orange Book)
BS 7671:2018+A4:2026 is the latest edition of the IET Wiring Regulations and provides the requirements for the design, installation and maintenance of electrical installations.
Amendment 4:2026 introduces significant changes across a number of areas of BS 7671, making it important for electricians and electrical professionals to study the current requirements when preparing for the 18th Edition examination.
Use the latest edition alongside our 18th Edition Mock Tests to practise applying the regulations and improve your exam preparation.
Buy the official BS 7671:2018+A4:2026 in print:
IET Wiring Regulations — BS 7671:2018+A4:2026
BS 7671:2018+A4:2026 IET Wiring Regulations — 18th Edition
BS 7671:2018+A4:2026, commonly known as the 18th Edition Wiring Regulations or Orange Book, is one of the most important reference books for anyone working with electrical installations in the UK.
Published by the Institution of Engineering and Technology (IET), BS 7671 provides requirements for the design, installation, inspection and testing of electrical installations. It is widely used by electricians, electrical contractors, designers, inspectors, engineers, apprentices and students studying electrical qualifications.
If you are preparing for an 18th Edition examination, having access to the correct and current edition of BS 7671 is essential.
What is the 18th Edition?
The 18th Edition refers to the current edition of the IET Wiring Regulations, BS 7671.
The regulations cover a wide range of electrical installation requirements, including protection against electric shock, overcurrent protection, earthing and bonding, cable selection, inspection and testing, special locations and many other aspects of electrical installation work.
BS 7671 is not designed to be read like a normal textbook. It is a technical standard and is intended to be used as a reference when designing, installing, inspecting and testing electrical installations.
This is particularly important when studying for the 18th Edition exam. You are not expected to memorise every regulation in the book. Instead, you need to become familiar with its structure and learn how to find the information you need quickly and accurately.
What does A4:2026 mean?
The A4:2026 part of the title refers to Amendment 4:2026.
This is an important update to BS 7671:2018 and introduces changes across several areas of the Wiring Regulations.
The updated publication includes requirements and changes relating to areas such as:
Electrical energy storage and stationary secondary batteries Power over Ethernet (PoE) Medical locations Functional earthing and functional equipotential bonding Inspection, testing and verification requirements
The consolidated publication brings the amendments together into the current BS 7671:2018+A4:2026 edition.
If you are studying for an examination based on the latest regulations, it is important to check that your copy of the book contains Amendment 4:2026 rather than relying on an older edition.
Why do you need the Orange Book?
For 18th Edition students, BS 7671 is the main reference document you will be working with during your studies.
A large part of preparing for the examination is learning how to navigate the regulations efficiently.
The book contains Parts, Chapters, Sections, Regulations, tables and appendices, all of which provide different types of information.
You will also use the Index to help locate relevant subjects and regulations.
For example, when answering a practice question, you may need to identify the subject being tested, find the appropriate section of the regulations and then check the relevant regulation or table.
The more familiar you become with this process, the easier it becomes to work through questions.
You don’t need to memorise the whole book
One of the biggest mistakes students can make is thinking they need to memorise hundreds of pages of regulations.
The more useful skill is knowing where to find the information.
Spend time becoming familiar with the layout of the book. Learn where the main Parts and Sections are located, understand how regulation numbers work and practise using the Index.
Then use practice questions to test yourself.
When you come across a question you cannot answer immediately, use BS 7671 to find the relevant information. This helps you learn both the subject and the location of the information within the book.
Over time, you should become faster and more confident at finding the correct regulation.
Using BS 7671 with mock tests
Mock tests are a useful way of putting your knowledge into practice.
Rather than simply memorising answers, use your copy of BS 7671 while studying to locate the regulations behind the questions.
For example, if a question relates to disconnection times, earthing, RCD protection, cable selection or a particular installation requirement, practise finding the relevant regulation yourself.
This develops an important skill: using the Wiring Regulations as a working reference.
Combining the Orange Book with regular mock tests can help you identify areas where you need further study and become more comfortable with the type of questions you may encounter.
Buying the correct edition
When purchasing BS 7671, always check the full title carefully.
The current edition for 2026 is:
BS 7671:2018+A4:2026 — Requirements for Electrical Installations, IET Wiring Regulations, Eighteenth Edition
Older copies can still be found through online marketplaces and second-hand sellers, but they may not contain the latest amendments.
If you are purchasing a used copy, check the edition, amendments, publication details and ISBN before buying.
The current publication is listed by the IET as a 640-page paperback with ISBN 978-1-83953-972-5.
Where can you buy BS 7671:2018+A4:2026?
The most straightforward option is to purchase the book directly from the IET Shop.
Buying from the official IET website allows you to check that you are purchasing the current BS 7671:2018+A4:2026 publication.
Buy BS 7671:2018+A4:2026 directly from the IET Shop
The price and availability can change, so check the IET product page for the latest information before purchasing.
Other useful IET books
Although BS 7671 is the main reference, there are other publications that can help with your studies.
The IET On-Site Guide provides practical guidance based on BS 7671 and can be useful for electricians and students who want additional practical information.
The Student’s Guide to the IET Wiring Regulations is aimed specifically at learners and can help explain the structure and use of the Wiring Regulations.
Depending on your course and career path, other IET guidance publications may also be useful, particularly if you are progressing towards inspection and testing or other electrical qualifications.
A good way to study
When you first get your copy of BS 7671:2018+A4:2026, take some time to become familiar with the book rather than trying to read every page from beginning to end.
Start by looking through the contents and understanding how the regulations are organised.
Then practise using the Index.
Look at the different tables and appendices and familiarise yourself with the regulation numbering system.
Once you are comfortable with the layout, start working through practice questions.
When you don’t know an answer, use the book to find it.
This approach helps you develop both your knowledge and your ability to navigate the regulations efficiently.
Prepare with Electrician Mock Test
At Electrician Mock Test, our resources are designed to help learners practise for electrical examinations using realistic questions and exam-style tests.
Our 18th Edition Mock Tests can be used alongside your copy of BS 7671:2018+A4:2026 to help you practise finding and applying the relevant requirements.
The goal is not simply to memorise hundreds of answers. It is to understand the regulations, become familiar with the structure of BS 7671 and develop the confidence to find the information you need.
Quick Reference
Publication: BS 7671:2018+A4:2026 Title: Requirements for Electrical Installations Edition: IET Wiring Regulations, Eighteenth Edition Common name: 18th Edition / Orange Book Publisher: Institution of Engineering and Technology (IET) Format: Paperback Pages: 640 ISBN: 978-1-83953-972-5
If you are preparing for the 18th Edition, make sure you are working from the current BS 7671:2018+A4:2026 publication and use it regularly while practising questions.
Learn the regulations. Learn how to find them. Practise applying them.