Electrical Installations - Topic Home



NB These pages are an introduction to domestic electrical installations. They are aimed at builders and surveyors who require a broad understanding of electrical installations rather than a detailed working knowledge. Do not attempt any electrical work on the basis of information contained in these pages.    NB These pages were written in 2005 - there may have been changes since then.

Nowadays it would be inconceivable to build a new house without an electrical installation. However, it was not until the 1920s that electrical installations were the norm in new housing - later still in rural areas. These early installations were comparatively simple - many just comprised an upstairs and downstairs lighting circuit. The main use of electricity in these early days was for lighting - it was safer and brighter than gas.  During the 1930s the use of electrical appliances slowly spread - the shops started to sell electric fires, washing machines, fridges, and vacuum cleaners. Many of the goods that we take for granted today; TVs, record players, and tape recorders, were not readily available until the 1950s. Video recorders became popular in the 1980s,  personal computers a few years later. To cope with all this equipment modern electrical installations, although not very complex, are  quite comprehensive. Modern installations are also much safer than their early counterparts.

Even so, according to Government statistics, each year on average 10 people die and about 750 are seriously injured in accidents involving unsafe electrical installations in the home. To help address this issue, the Construction Industry Deregulation Task Force recommended in 1995 that electrical safety requirements should be included in the Building Regulations.  A new Approved Document (Part P) now includes:

  • Guidance relating to the design, installation, inspection and testing of electrical installations.
  • Guidance on types of electrical work that would not normally need to be notified to building control bodies (see left-hand link)
  • Appendices that contain illustrations of the sorts of electrical services commonly required in homes, examples of model electrical installation certificates, and illustrations of what equipment may be encountered when work is carried out on older electrical installations.
The Regulations are actually very short.  Approved Document Part P (Electrical Safety) states that:
  • "Reasonable provision shall be made in the design, installation, inspection and testing of electrical installations in order to protect persons from fire or injury.
  • Sufficient information shall be provided so that persons wishing to operate, maintain or alter an electrical installation can do so with reasonable safety."

In the UK new electrical installations have to conform to the IEE Wiring Regulations (Institute of Electrical Engineers). The IEE manages the national committee which prepares and updates the regulations for the safety of electrical installations in buildings, and publishes the standard BS 7671:2001 (the IEE Wiring Regulations). It also provides and publishes extensive guidance upon the standard as well as related codes of practice.

These few 'pages' on electricity do not attempt to explain the details of BS 7671. Their purpose is to help the reader understand how a modern electrical installation works and be aware of some of its key safety features. Other sections also includes details of potential hazards, common defects, and the purpose and scope of domestic periodic inspection.

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