Anticipating the seventeenth edition of the Wiring Regulations
Many electrical engineers and electricians have only ever known the sixteenth edition of the Wiring Regulations, but the forthcoming seventeenth edition will be less of a culture shock than the change from the fifteenth to sixteenth edition in 1991.Although the technical development of electrical engineering and installations comes nowhere near to matching the frenetic pace of the electronics industry, new technologies do, nevertheless, evolve — requiring updates in the standard governing electrical installations. The IEE Wiring Regulations govern electrical installations in buildings. Now known as BS 7671 since 1992, the ‘Wiring Regs’ have a long history — with the first edition having been published in 1882. The current edition is the sixteenth, published in 1991 and coming into full effect at the beginning of 1993. It was last reprinted in 2004. By the electrical industry’s own admission, a new edition of the Wiring Regulations is long overdue, and the seventeenth edition is due to be published on 1 January 2008— coming into full effect relatively quickly on 1 July 2008. Between those two dates, electrical installations can be designed to either the sixteenth or seventeen edition, but all installations designed after 1 July 2008 must comply with the new BS 7671. Controversy The months since the draft was published have been full of controversy and debate in the industry — and many issues are not expected to be settled until very close to the deadline for printing. The driving force behind the new regulations is the need for them to incorporate changes made necessary by a combination of new technologies, products and continuing harmonisation. Even when the seventeenth edition has taken account of these changes, informed sources in the electrical industry expect no let up on this progress as time goes by. Such is the scale of the changes required for harmonisation that very little national (i.e. UK) text remains. Interest in the new regulations runs high, as demonstrated by the large attendances at seminars organised by the Electrical Contractors’ Association at 12 venues across the country, with two sessions at each venue — one for those who appoint electrical contractors and one for contractors themselves. The ECA is also playing a key role in training and certification for the new regulations — with three routes to qualification, in addition to a choice of two awarding bodies for its training courses. There is more on the ECA web site (www.eca.co.uk). Indeed, the Electrical Contractors’ Association’s technical committee was involved in writing the new regulations. One of the specific requirements of the new standard is for appropriate documentation for projects, which Stephen Plant, ECA’s regional education and training manager, interprets as a schedule for small installations such as domestic. Competence He also highlights specific requirements for ‘good workmanship by competent persons’ or persons under their supervision, and proper materials. There is also a requirement for inspection and testing to be carried out by a ‘competent person’ — and it is the responsibility of the designer to specify the interval to the first periodic inspection. Stephen Plant’s interpretation is, ‘Competency is a marrying of knowledge and experience. Either one without the other may be dangerous.’ The regulations themselves also have a definition of a competent person as ‘a person who possesses sufficient technical knowledge and experience for the nature of the electrical work undertaken and is able at all times to prevent danger and, where appropriate, injury to themselves and others’. Many other terms which are generally understood, now have a definition. They include verification, inspection, testing and reporting. One old favourite highlighted by Stephen Plant is the modified definition of an exposed conductive part as ‘a conductive piece of equipment which can be touched and which is not live but which can become live when basic insulation fails’. An example is metal switch plates. Another new definition is replacement of phase conductive with the internationally used term line conductor — which is not to be confused with a live conductor, which can be a neutral conductor. In a similar vein, two types of protection are defined. One is the replacement of direct-contact protection with basic protection — not being able to touch parts that are meant to the live. The other is fault protection — to provide protection if exposed metal parts become live. RCDs One of the aspects of the new regulations that differentiates it from the previous edition is its emphasis on RCDs as protective devices for all circuits, including lighting, and both upstairs and downstairs in houses. Their inclusion is in recognition of the addition protection they provide — a term that is now used instead of supplementary protection. Darrell Locke, the author of a new ECA book on the new regulations due out early next year, says that the pressure for RCDs has come from manufacturers, and that the ECA and others did not want them as a prescribed method of protecting against risk. RCDs are now required for all general-use socket outlets rated up to 20 A. Two exceptions are allowed. One is a socket outlet used under the supervision of skilled or instructed persons — which could exempt commercial premises such as offices. The other is a socket outlet identified for connection to a specific piece of equipment; one suggestion is a freezer to protect it against nuisance tripping. To be recognised as giving additional protection, an RCD must be rated at 30 mA or less and operate within 40 ms when tested at five times rated operating current. A potential benefit of RCD protection is that 13 A sockets will be allowed in bathrooms, as long as they are not closer than 3 m to a bath or shower — a large bathroom indeed. There is a hint that it may be possible to install a washing machine in a bathroom. Another significant change for bathrooms is that supplementary bonding will not be required, provided any required protective equipotential bonding has been installed. Part 5 on the selection and erection of wiring systems also has much to say about RCD protection for cables concealed in partitions or walls at a depth of less than 50 mm. RCD protection of 30 mA or less is required for such cables that are not intended to be under the supervision of skilled or instructed persons and where traditional protection cannot be provided (such as earth metallic covering, earthed metallic conduit or equivalent protection from nails, screws etc.). In addition, PVC/PVC cables concealed in walls in domestic installation at a depth of less than 50 mm will need to be in a safe zone and have additional RCD protection. Finally, if a wall has any metallic construction, RCDs will be required irrespective of the depth of the cable. The question that immediately concerns electricians is lighting circuits with the switch cable going to a plate switch. Products are appearing on the market that offer remote control of light fittings; perhaps these new requirements will open up a market opportunity. Also covered in this part of the regulations are busbar trunking and powertrack systems. Developments in technology are reflected in Part 7, with sections on solar photo-voltaic power systems and electric floor and ceiling heating systems. One of the principal aims of the Wiring Regulations is to protect against the dangers of electricity, and Stephen Plant refers to one of Hillaire Belloc’s cautionary verses written during the time of the first Wiring Regulations in 1882, which he describes as as relevant today as it was then. Lord Finchley tried to mend the electric light. It struck him dead — and serve him right! For ’tis the duty of the wealthy man to give employment to the artisan. — fully competent to BS7671:2008, of course! Long overdue — the seventeenth edition of the IEE Wiring Regulations.