The 17th Edition of the Wiring Regulations is almost upon us. The ECA gives a brief overview of what contractors can expect come 1 January 2008.

The 17th Edition of the Wiring Regulations is scheduled to be published on 1 January 2008. Between that date and 1 July 2008 either the 16th or the 17th Editions can be used. All installations designed after 1 July must comply with the 17th Edition. What changes can contractors expect?

Preface. An informative note advises that publication of the 2008 edition of BS7671 does not automatically mean installations complying with previous editions are unsafe for use or need upgrading.

Numbering. The Regulation numbers are changed so as to be in line with IEC numbers (see ‘Standard practice’ box). This enables users to relate UK regulations with European harmonised documents (HDs) and IEC regulations.

Fundamental principles. Requirements are added for protection for persons and livestock against injury, and property against damage caused by voltage disturbances and electromagnetic influences.

Protection against electric shock

This chapter has been rewritten. Many regulations are worded differently, but the requirements are not significantly changed.

The terms ‘direct contact’ and ‘indirect contact’ are no longer used. They are replaced with ‘basic protection’ and ‘fault protection’.

‘Basic protection’ is protection against touching live parts. ‘Fault protection’ is protection against receiving a shock from conductive parts that have become live due to a breakdown of insulation or damage to equipment.

Socket outlets rated not exceeding 20 A and intended for general use by ordinary persons must be protected with 30 mA RCDs. This means that general purpose sockets in domestic and similar properties must have RCD protection.

External sockets rated not exceeding 32 A must also have 30 mA RCD protection.

Selection and erection of wiring systems

An important new regulation that particularly affects domestic and similar installations requires cables that are buried less than 50 mm into a wall or partition and are not enclosed in earthed metallic covering or have mechanical protection capable of resisting nails, screws or drills, to be protected by a 30 mA RCD.

Similarly, cables that are installed in metal-framed walls require 30 mA RCD protection, if not otherwise protected by earthed metallic covering.

The above requirements do not apply to installations that are under the control of skilled or instructed persons, such as office buildings, large retail outlets and industrial premises.

Other equipment/ generator sets

This section contains requirements that are applicable to low-voltage electricity generating sets including: wind turbines, solar-powered generators, photovoltaic systems (also covered in Section 712), water turbines and combined heat and power for use in domestic and commercial installations.

Luminaires and lighting

  • This is a new section applicable to all general lighting installations as appropriate to particular locations and structures. It includes:
  • Requirements for fixed outdoor lighting including highway power supplies and street furniture previously in Part 6, and extra-low-voltage (less than 50 V ac and 120 V dc) lighting systems.
  • Both individual luminaires and multi-luminaire track lighting and similar systems.
  • Special considerations for protection against fire.

Special locations

Part 7 addresses the particular risks that occur in special locations. Many of the existing sections have been modified in line with the European HDs:

701 – Locations containing a bath or shower

  • The changes from the 16th Edition are particularly substantial here: Zones 0, 1 & 2 as defined in the 16th Edition are retained. Zone 3 is removed. New regulations require all circuits supplying equipment in the bathrooms to be protected by 30 mA RCDs.
  • All cables buried in walls surrounding bathrooms, regardless of the points they are serving, have to be protected by 30 mA RCDs.
  • Supplementary bonding between metallic service and waste pipes and the earth connections of equipment is no longer required, providing the main bonding of services within the property is in place and the metallic pipework can be proved by testing to be continuous.
  • This means green and yellow cables in bathrooms are unlikely to be necessary.
  • SELV (separated extra-low voltage) socket outlets and shaver socket outlets are permitted outside Zone 1.
  • 230 V socket outlets are permitted provided they are more than 3 metres from Zone 1.

702 – Swimming pools

  • Zones A, B and C have been replaced by Zones 0,1 and 2. Scope now includes basins of fountains.

703 – Rooms and cabins containing sauna heaters

  • Zones A, B, C and D are replaced with Zones 1, 2 and 3.

704 - Construction sites

705 - Agricultural and horticultural premises


  • In both the above sections the reduced connection time of 0.2 s and the 25 V equation have been removed.

706 - Conductive locations with restricted movement

707 - Previously 607 in the 16th Edition

  • Not used. The particular requirements are embodied in the general earthing requirements of Chapter 54.

708 - Caravan and camping parks

  • This was formerly caravans, motor caravans and caravan parks in the 16th Edition. The section is now divided into Section 708 and Section 721 - Caravans and Motor Caravans.
  • Of particular note, each pitch socket outlet is to have separate 30 mA RCD protection.

There are several new sections in Part 7.

709 - Marinas and similar locations

711 - Exhibitions, shows and stands

712 - Solar photovoltaic power supply systems

717 - Mobile or transportable units

721 - Caravans and motor caravans

740 - Temporary electrical installations for structures, amusement devices and booths at fairgrounds, amusement parks and circuses

In the lead up to the final publication date, the 17th Edition could change considerably or face delays.

Contractors would be advised not to enrol on courses prematurely.

Standard practice

BS 7671: 2001 is the national standard for all electrical installation work undertaken in the UK. It has also been adopted by a number of other countries. The first edition of BS 7671 was published in 1992 when the then British Standards Institution (BSI) adopted the 16th Edition of the IEE Wiring Regulations and made it a national standard.

The British Electrotechnical Committee (BEC) is part of the BSI and is the UK member of the International Electrotechnical Commission (IEC) and CENELEC (the European Committee for Electrotechnical Standardisation).

The purpose of the IEC and CENELEC is to create global and European commonality of electrical installation standards.

The standards thus created are known as harmonised documents (HDs). BS 7671 is the UK HDs incorporated in a single publication with many other regulations applicable in the UK.

BS 7671 has been amended six times since the first publication in 1992. The 17th Edition is the result of a complete review of the 16th Edition and adopts all HDs published to date.

Horses for courses

The ECA is preparing training courses for contractors.
Member firms will be required to demonstrate competence to design and install electrical services in accordance with the new regulations during future membership competence assessments.

There will be three options:


  • assessment only, for existing ECS gold cardholders, cost £50;
  • a one-day course for those who have passed a BS 7671 course since 2001;
  • a three-day course for those who are qualified but who are looking for an in-depth overview of the 17th Edition, or who have not passed a formal BS 7671 qualification since 2001.

Costs for the one- and three-day courses are £125 plus VAT for ECA members and £187 plus VAT for non-members per day.

Discounts are available for non-members that are registered to Part P schemes run by NAPIT, BRE Certification and NICEIC, with further discounts for those on Elecsa’s register.

More information can be found online at: www.eca.co.uk/17thedition

Source

Electrical and Mechanical Contractor