Despite good standards in domestic electrical safety, there are over 30 deaths, 4,000 injuries and over 8,000 fires each year in British homes due to electrical faults, according to government figures. Most of the fires are caused by faulty electrical wiring. Misuses of appliances, a system overload, poor maintenance and defective DIY account for the remainder.
A large proportion of British housing stock has electrical wiring that was not designed for the high power requirements of today`s appliances. This is as true for smart phones and plasma televisions as it is for electric ovens. Modern electronic devices account for the massive surge in electricity demand over the past decade.
In London and other major British cities, the biggest electrical safety issue is aluminium wiring. The heat generated during electrical transmission expands, contracts and oxidises the aluminium conductors. The wiring disintegrates, insulation corrodes and causes electrical arcs and fires.
Aluminium was used in wiring instead of copper between the mid-1960s and 1980. It replaced copper as an economy measure during a time of high world copper prices. Though only a short period, it coincided with intensive new house building programmes as well large scale conversions of older properties into flats.
Even the best designed electrical systems deteriorate with age. Regular testing will ensure that the electrical installation remains safe and serviceable. These tests will determine whether the circuits in a house or the appliances used are overloaded.
The test will locate risky areas that could cause electric shocks, as well as identify old and defective DIY work. The test will also identify earthing problems and departures from statutory electrical standards.
Electrical testing is a statutory obligation for all public and commercial building as well as for rented accommodation. Electrical safety r0ules in all buildings, including private dwellings were introduced in 2005. All electrical work must be carried out by a registered electrician.
Such tests should be conducted at least once every five years. The tests may be dangerous for both the technician conducting the test and any bystanders.
There is a correct sequence for testing the safety of a domestic electrical installation. With the power supply switched off, it starts with a visual inspection of any damage or corrosion. This includes fittings, missing covers, exposed cables, switchgear and distribution boards.
Cables, especially, deteriorate because of overheating and inadequate fixing. Although fitting and socket covers can be removed during the test, parts of cables may be embedded in the structure of the house and are inaccessible. These tests usually do not include the dismantling of a house.
With the power supply switched on, a live test includes the examination of switches, isolators and insulation. The most important live test is the earth fault loop impedance. This checks the resistance of a live conductor to the earth and the effectiveness of the earthing system. It shows whether a current created during a fault will blow a fuse or trip a circuit breaker, or spark a fire.
Today, domestic electrical testing is a professional undertaking. It is not a job for a DIY enthusiast with a hammer and a couple of screws. Domestic electrical safety should be a priority for all householders.