The top electrical faults likely to affect a domestic electrical system

This article is designed to provide you with some valuable information on common inadequacies within a domestic electrical installation.

Although electrical Inspections can be conducted by any competent electrician with the appropriate equipment, remedial works particularly notifiable ones need to be conducted by a part P qualified electrician and the appropriate building controllers notified.

Should your electrician be a member of any of the below competent persons schemes they can self certify the installation.

Competent persons schemes members

• British Standards Institution (BSI)
• EC Certification Limited / ELECSA
• NAPIT Registration Limited (National Association of Professional Inspectors and Testers)
• NICEIC Group Limited

Common electrcial fault No.1 - Lack of RCD protection on Fuseboard

One of the most common defects with domestic electrical systems is the lack of RCD protection on the consumer unit.

The new Wiring Regulations BS 7671 came in to force at the end of June 2008, requiring much more extensive provision for RCD (residual circuit protection) of both domestic and non-domestic dwellings. The practicalities of meeting those requirements for protection are varied and too numerous to list in this article but examples of the implications are below.

• All power sockets sockets from 13Amp – 20Amp for use by ‘ordinary persons’ should normally be protected by a 30mA RCD.
• In bathrooms for example RCD protection is now required for all circuits.

In summary there are a number of approaches to fuse board design to meet the new regulations, some of which utilise traditional RCD main switch consumer units and split load consumer units, while others rely on the new type of dual RCD protected consumer units. In general the use of RCDs and RCBOs is now greater and there is a trend towards larger consumer units with more ways available.

Common electrcial fault No.2 - Partial or incomplete bonding

Electric shocks caused by faulty appliances and charged metallic objects can be fatal. Therefore it is of paramount importance all metallic items like gas and water pipes within a property are properly earthed in order for electricity to be dispersed safely. Bonding is the term used for connecting all metallic items that do not normally carry a current (pipes etc) within a property, together and to the mains earth to prevent electric shocks.

In each electrical installation, main bonding conductors(earthing wires) are required to connect to the main earthing terminal for the installation of the following:

• metal water service pipes
• metal gas installation pipes
• other metal service pipes and ducting
• metal central heating and air conditioning systems
• exposed metal structural parts of the building
• lightning protection systems

Common electrcial fault No.3 - Inappropriate fittings in a bathroom

For Electrical safety, bathrooms pose a greater risk of electrocution due to the proximity of water. Electrical appliances commonly found here need to demonstrate higher levels of protection in compliance with section 601 of the new wiring regulations.

• Lighting
• Extractor fans
• Shaver sockets
• Towel rails

Electrical equipment used in bathrooms must not be adversely effected by environmental factors.

• Condensation
• Humidity/steam
• Drops of water
• Sprays from showers

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