08 June 2009
Jim Wallace

BS 7671: Requirements for Electrical Installation - more commonly known as the IEE Wiring Regulations - is the national standard to which all domestic and industrial wiring has to conform. The 17th edition, which came into force last year, included substantial changes to harmonise with EU regulations. If you are responsible for workplace safety and have electrical work done on your premises, you should have a rough idea of what the Regulations say.

BS7671: 2008 is an acceptable means of demonstrating compliance with the Electricity at Work Regulations 1989. The requirements of this new edition apply to all new electrical installations and alterations since July 2008.

Among the changes to Regulations'  scope and principles is the inclusion of four new regulations for the protection of people and livestock against voltage disturbances and electromagnetic influences. There is also a specific requirement for appropriate documentation for all installations.

Though there are still seven parts to the Regulations, the updated version has been completely restructured and adopts the IEC numbering system. Many chapters have been completely rewritten and many of the changes are technically complex. Seven new appendices have been added. Also, seven new special locations are covered to address the risk associated with certain environments or facilities, including exhibition areas, mobile units and temporary installations.

There are also important changes to terminology and definitions, with the 17th edition incorporating 90 extra definitions alongside the original 170 in the 16th edition, which had been in force since 1991.

Inspection and testing

One of the features of most interest to health and safety managers in the new edition is Regulation 134.2.1, which requires that inspection and testing must be carried out by a "competent person" to check the work meets  required standards.

It defines a competent person as someone "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".

In practice, this means experienced engineers who have been through the City & Guilds 2392-10 Fundamental Testing, Inspection and Initial Verification course. For periodic inspection and testing, competent persons should have the City & Guilds G 2392-20 Inspection, Testing and Certification of Electrical Installations certificate as well.

Once the installation has been verified initially, both inspected and tested, the competent person can issue an Electrical Installation Certificate, together with a schedule of test results and a schedule of inspections. The certificate includes space for three signatures: the person responsible for the design, the person responsible for the installation and the person carrying out the inspection and test.

The signatory for the inspection and test section must be the person who actually carries out the inspection and test, and not someone else in authority. In some cases, the same person may end up signing all three sections, and that's perfectly acceptable. But the Electrical Installation Certificate should not be signed until any defects noted in the inspection and test have been corrected.

Where the work involves altering or adding to an installation, the competent individual must issue an Electrical Installation Certificate as above (or a Minor Electrical Installation Works Certificate, see below), stating the extent of the works covered, once the inspector is satisfied that the works comply with the Regulations.

They should report in writing defects they find in related parts of the installation, but which don't affect the safety of the alteration or addition to the person ordering the work. If existing defects do affect the new work then they must be corrected before an Electrical Installation Certificate is issued and before the new work is put into service.  

Coming back to it

After the initial testing, the 17th edition Regulations positively recommend (Regulation 135.1) that every electrical installation is subject to periodic inspection and testing by a competent person.

They say the designer of the installation is responsible for specifying the interval to the first periodic inspection and test. The IEE Guidance Note for periodic fixed installation test frequencies advises a maximum period of five years between inspections and testing for commercial offices, shops and hospitals, but this drops to three years for industrial facilities and leisure complexes. For some special installations, such as petrol stations, the maximum period between inspections and testing is one year. This marks a big change from the previous edition which presumed that a programme of risk assessments, records and preventative maintenance could be adopted instead of periodic testing.

The Periodic Inspection Report form is only to be used for the inspection of an existing installation and should include both inspection and test results. Again the report should define its extent and make recommendations of defects and remedies. There is a numbering system for this purpose:
1:  Requires urgent attention
2:  Requires improvements
3:  Requires further investigation
4:  Does Not Comply With BS 7671:2008 (though this does not necessarily imply that the electrical installation is unsafe).

Several associations and trade bodies allow the issuing of a Minor Works Certificate. A minor work is anything that doesn't include the provision of a new circuit. Testing is still essential and the 17th edition identifies several tests as essential to confirm safety.

Jim Wallace is research and technology manager at Seaward Electronics, http://www.seaward-group.co.uk/

Categories:
Safety, Article, Manufacturing / engineering