17th Edition

The bs7671 17th Edition was the specific wiring regulations guidance book previously used by those in the electrotechnical industry. It was in circulation as a key standard between 1st July 2008 and 31st December 2018. Since 1882, the IET has released wiring regulations documentation to provide compliance support for those in the electrical sector. The IET, or the Institute of Engineering and Technology, is a highly-reputable body that seeks to represent electrical professionals. They also advise governments on all endeavours alluding to engineering work.

Non-statutory, but incredibly important

The basic function of these guides is to establish a fixed set of rules and principles that any electrical installation must adhere to. The regulations offered are the standard code of practice for all industry professionals. Any wiring regulations book, regardless of edition, will aim to link the specific elements of the installation process to the corresponding sections of its text. It also demonstrates the way in which electrical work should be conducted, and how electrical professionals can comply with key governmental legislation. This incorporates important legal covenants. Some examples of which are the Electricity at Work Act of 1989, and the Health and Safety at Work Act of 1974.

The wiring regulations are ultimately a non-statutory piece of documentation. However, they have a substantial level of credence in the sector. Given this, and the fact that they’re referenced in multiple parts of UK statutory law, they can actually be deployed in a legal context. Therefore, they are sometimes utilised for this purpose in a court of law.

History and Context

New editions are published by the IET every so often, with timeframes between each release varying between roughly 5 and 15 years. The latest set were introduced in July 2018, with an official industry ‘go-live’ date of 1st January 2019. This is the same process undertaken for previous editions; the IET facilitates a period of time for individuals to digest, understand, and practice the regulations before their incorporated into compliance expectations.

The regulations are also endorsed by the BSI (The British Standards Institution). The BSI is the industry-acknowledged body that establishes standards, in the UK, across a wide number of sectors. They also provide certification to demonstrate competency levels of working professionals.

It is critical that those completing electrical installations are fully versed on the latest edition of regulations. Unfortunately, there are occasions where electrical ‘professionals’ do not keep across recent changes. At best, this can undermine the standard of work. At worst, this can put clients, buildings, and those conducting the work at serious risk of injury, or even death.

Available Courses

For those looking to stay abreast of the changes, the City & Guilds provide a one-day ‘update’ course. For reference, City & Guilds is a universally-recognised skills body. They work across a number of industries to provide training and development for individuals and organizations alike. This course is designed for experienced electricians, and have a comprehensive understanding of the previous regulations. Through this method, candidates can ‘top-up’ knowledge, as opposed to sitting an in-depth course.

C&G also conduct a full, 4–5-day course, directed at students and industry novices. This enables newcomers more time to understand the regulations in their entirety. By the end of the course, they should feel confident in their understanding of the guide’s theoretical elements. Moreover, they should start to consider the practical application of this theory in real-world scenarios.

Course structure and format

However, these courses are clearly now rendered obsolete given that the 18th edition book is now in operation. The course code was C&G: 2382-15, but this has now been updated to C&G: 2382-18. As per all contemporary wiring regulations guides, this course was offered by a range of educational institutions and private course providers. Candidates were able to either undertake an online or classroom-based course journey. Course duration was dependent on personal circumstance. Most course facilitators established a standard four-to-five-day course, but also had the provision to offer an evening programme. Important for those with other personal commitments. Although the latter provides a better level of flexibility, its’s worth noting that this course would be stretched out over a prolonged period of time (often upwards of a month or two). Therefore, the compact approach has been traditionally favoured when undertaking this qualification.

It’s perhaps worth noting at this stage that a basic level of electrical theory should be acquired before considering registering for any wiring regulations course. Otherwise, candidates will feel quickly left behind. City & Guilds have always offered foundation learning modules to get individuals up to a rudimentary knowledge level. This may be something you’d like to consider in the present context. If so, then please visit the City & Guilds website for more information.

The Assessment

To have become an electrical installer, all individuals needed to have passed the edition’s associated test. This assessment was scheduled for the conclusion of the training period. However, in alignment with today’s requirements, further training and certification had to be undertaken before the status of fully-qualified electrician was achieved.

It would have been essential that appropriate revision time was allocated to undertake this assessment. Although individuals would not have needed to learn the guide cover-to-cover, there was still a substantial level of detail involved.

Other Professions

An understanding of the wiring regulations can be extremely useful for those on the periphery of the electrotechnical industry. There are a variety of professions which can benefit from this knowledge. These include engineers, maintenance managers, project managers and architects etc.

By grasping this information, such individuals can complement their approach with an appreciation of the requirements and limitations of electrical installations. Subsequently, this allows relevant works to be planned more accurately. Given the technical jargon and developed electrical theory present in the guide, these candidates may find the assessment a little tougher. However, this information will provide increased confidence and efficiency in disciplines that otherwise may have caused substantial headaches.

Detailed content overview

The size of the 17th edition book may have felt a little overwhelming at first. There are 389 pages included (in rather small font!), with an abundance of technical jargon and detail.

However, as subtly referenced, the guide did not require candidates to learn its content off by heart. Rather, the book affords, as the 18th edition does today, the opportunity to apply its information in practical terms. In this way, individuals should aim to read and understand the general themes of the book, and consider their real-world application. If learned in isolation as disconnected words on a page, then students will find the guide far more challenging than it needs to be. The method of trying to commit each sentence to memory can sometimes be tempting when revising for an assessment. However, the questions posed will be positioned in such a way that seeks to understand your holistic grasp of the guide, not whether you can recite hundreds of regulations unaided.


Any wiring regulation guide can be subjected to future amendments. This allows the IET and BSI to implement small-scale changes, without having to publish a full next edition. In relation to the 17th wiring regulations guide, the book harnessed several changes over a four-year period. Amendment 1 was incorporated in 2011, Amendment 2 in 2013, and Amendment 3, the final adjustment, came in 2015. It is not compulsory for electrical installers to re-take an earlier assessment that has now been altered with the new amendments in-play. However, they must ensure they conduct all electrical instalments to the updated standard.

When a new amendment is introduced, as was the case for the 17th edition, a fresh book (but not a fully updated edition) is released. This is usually produced in a different colour. Given the volume of amendments, the 17th edition had three new books. This starting out as red, then changed to green, before the final version was produced in yellow. The latest manifestation of the book was entitled, ‘Requirements for Electrical Installations: bs7671: 2008 Incorporating Amendment No 3: 2015, in order to reflect the final update.

Conditions for the application of the regulations

In essence, the book refers to the design, erection, and verification of electrical instalments. The guidance, principles, and rules offered relates to work conducted on:

  1. Circuits which are powered at a nominal voltage up to 1000V A.C, and use frequencies of either 50Hz, 60Hz or 400Hz. Also, circuits which are supplied at a nominal voltage up to 1500 V D.C.
  2. Circuits, aside from those involved with the internal wiring of equipment, which operate at voltages over 1000V and conducted from an installation which has a voltage current lower than 1000V A.C.
  3. Wiring systems and cables which are not covered by compliance standards for electrical appliances.
  4. Any consumer installs external to a building.
  5. Wiring deployed for ICT (information and communication technology), signalling and control. This includes any addition or adjustment to the install, and also any elements of the original installation impacted by such alterations.

Book content

The book is split down into seven ‘parts’ Within Part 7, there is an accompanying Appendices. These parts (excluding Part 2) allude to the varying stages of the electrical instalment process. Therefore, individuals can feel rest assured that any electrical work conducted can be fully supported, from design to implementation, via the contents of this guide.

Part 2 contains a comprehensive list of definitions. It therefore complements Parts 1,3,4,5,6 and 7, as opposed to holding presence as a standalone section with ‘new’ information. Candidates should lean on this section when unsure of any terminology or acronyms deployed. The Appendices similarly serve as a helpful mechanism for learning. These contain various figures, tables, and graphs, which facilitate a stronger understanding of the electrical components deployed throughout the guide.

The full list of ‘parts’ included is as follows:

  • Part 1: Scope, object and fundamental principles
  • Part 2: Definitions
  • Part 3: Assessment of General Characteristics
  • Part 4: Protection for Safety
  • Part 5: Selection and erection of equipment
  • Part 6: Inspection and Testing
  • Part 7: Special Installations or Locations


There are a total of five appendices included in the guide, relating to various key elements. These are as follows:

  • Appendix 1: Standards and Bibliography
  • Appendix 2: Popular Cables current rating tables from bs7671: 2008 Appendix 4 4E1A, 4E4A, and 4D5A (samples only)
  • Appendix 3: Limiting earth fault loop impedance tables from bs7671: 2008
  • Appendix 4: Cable data-resistance, impedance and R1 and R2 values.
  • Appendix 5: Fuse I2t characteristics.

For the 17th edition, IET actually provided some additional appendices online. These are labelled as Appendices 10-18. They are documented on a ‘Companion Website,’ and can be accessed using this link: www.wiley.com/go/eca_wiringregulations

The texts included on this webpage refer to the following subjects:

  • Appendix 10: Example cable sizing locations
  • Appendix 11: Impedances of conduits and trunking
  • Appendix 12: Earth electrodes and earth electrode testing
  • Appendix 13: Notes on Out of Reach/Obstacles/Non-conducting Location/Earth-free Local Equipotential Bonding
  • Appendix 14: Additional ‘occasional’ tests that may be required
  • Appendix 15: Notes on periodic inspection and testing
  • Appendix 16: Electrical Research Association (ERA) report on armoured cables with external CPCS (circuit protective conductors)
  • Appendix 17: A4 sample versions of ECA bs7671: 2008 certificates and forms
  • Appendix 18: Building Standards in Scotland

As referenced, the appendices provide a tool to consolidate learnings. So, it’s well worth checking these sections located both online, and in the guide itself.


So, there you have it, a comprehensive overview of the 17th edition wiring regulations guide. Hopefully, this has served to give you a better understanding of the contents, function, and format of the book. The 18th edition guide is now the version in operation, so please ensure you suitably familiarise yourself with the information contained in that publication. If you have any questions relating to any edition of the wiring regulations guide, please either speak to your course convenor, or a trained, industry professional.