With more and more UK services consultants winning contracts overseas, electrical design engineers can no longer rely simply on their knowledge of the British Wiring Regulations Â– they need an understanding of the codes used across the world. Fortunately there is some crossover, stemming from a shared base, such as the International Standards (IEC).
In the UK, BS 7671:2008 Requirements for Electrical Installations, IEE Wiring Regulations 17th Edition, comes into force on 1 July. The joint IET/BSI technical committee JPEL/64 (UK National Committee for the Wiring Regulations) is responsible for the maintenance of this standard. The regulations are based on European Standards (CENELEC), which in turn are based on International Standards.
The Wiring Regulations are the national standard in the UK for electrical installations up to 1000V AC or 1500V DC. They are also used in other countries, such as Mauritius, St Lucia, Sierra Leone, Sri Lanka and Uganda, and yet more countries adopt the general principles of BS 7671.
It is not only the UK that will see a new issue of Wiring Regulations this year. In the USA, engineers will be familiarising themselves with the National Electrical Code (NEC) 2008 Edition, which was approved by the American National Standards Institute last August.
The NEC, also known as NFPA 70, is the US standard for the safe installation of electrical wiring and equipment, and is part of the National Fire Codes series published by the National Fire Protection Association.
Unlike the BS 7671 Wiring Regulations, the NEC is updated and published on a three-year cycle. It is used in a number of other countries and has been translated into Japanese, Korean and Spanish.
The construction boom has made the United Arab Emirates a popular destination for UK engineers. They need to be aware, however, that the individual states have their own wiring regulations.
In Dubai, all electricity and water is supplied and regulated by the Dubai Electricity and Water Authority (DEWA). It has adopted most of the codes and regulations that we follow in the UK, specifically the BS 7671 Wiring Regulations, and in 1997 issued its Regulations for Electrical Installations. If an amendment, addition or revision is required, DEWA issues a memorandum informing the designer of the relevant information.
Abu Dhabi conducted a review of the three forms of wiring regulations, and consequently the Regulation and Supervision Bureau for water and electricity issued the Electricity Wiring Regulations 2007. The document adopted predominantly UK and European standards for the design of electrical systems and specification of equipment.
QatarÂ’s electricity and water corporation, Kahramaa, publishes its own wiring regulations, as does BahrainÂ’s Ministry of Electricity & Water. The general principles are consistent with BS 7671.
To be effective, wiring regulations must be suitable for for a countryÂ’s electrical infrastructure and electrical safety system. They must be capable of being interpreted, applied and enforced uniformly. They must also have compatibility with additional standards applicable to products whose installation, use and maintenance is intended to be governed by the wiring regulation standard.
Obviously, there are differences between each countryÂ’s specific regulations. A comparison analysis would not only highlight differences in the engineering principles and fundamental standards, but also in their applicability. For example, a comparison of the BS 7671 and NEC documents reveals that:
Â• both address installation, use and maintenance of premisesÂ’ wiring systems and equipment;
Â• both are applicable to wiring systems of premises for residential, commercial and industrial use;
Â• neither covers installations for generation, transmission or distribution of electrical energy;
Â• the NEC is a comprehensive set of electrical installation requirements that can be adopted and implemented without the need of additional standards;
Â• BS 7671 must be supplemented by the requirements or recommendations of certain other British standards (such as BS 5839-6:2004 Fire detection and fire alarm systems for buildings);
Â• BS 7671 is limited to installations within two nominal voltage ranges (i) extra-low voltage Â– normally not exceeding 50V AC or 120V ripple-free DC (ii) low voltage Â– normally exceeding extra-low voltage, but not exceeding 1000V AC or 1500V DC between conductors, or 600V AC or 900V DC between conductors and earth;
Â• both standards need effective co-ordination with appropriate product standards to be successful in implementing electrical safety.
The ultimate aim is that all countries will have the same wiring regulations. National differences make this still a dream, but we are moving slowly in that direction. Until then, UK electrical design engineers will need to ensure that designs for overseas projects comply with the wiring regulations of the location.