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[ Update: BS7671:2008 ]


First amendment T


Giuliano Digilio, ECA head of technical services, provides an introduction to the proposed first amendment to BS 7671:2008 Requirements for Electrical Installations (17th Edition of the IEE Wiring Regulations)


he first amendment to BS 7671:2008 Requirements for Electrical Installations will be issued on 1 July 2011 and is intended to come into effect on 1 January


2012. Installations designed after 31 December 2011 are to comply with BS 7671:2008 incorporating Amendment No. 1 2011. Here’s a summary of the main proposed


changes. This is not an exhaustive list, and there may be other further changes, amendments or additions not mentioned below. For more infromation call the ECA technical department on 020 7313 4826/4829.


New numbering system The 17th Edition introduced a new IEC decimal point numbering system to make it easier to embody future changes and additions resulting from ongoing international standards work within IEC and CENELEC. In order to accommodate future IEC changes, it has been decided to have a 100 numbering system for UK-only regulations. Chapter 41 – Protection against electric shock Regulation 411.3.3 (c) now permits an exception (for the exclusion of additional protection via an RDC) for minor works where the designer is satisfied that there would be no increased risk from the addition or alteration. Chapter 44 – Protection against voltage disturbances and electromagnetic disturbances A new Section 444 has been added, which deals with measures against electromagnetic disturbances. Electromagnetic interference (EMI) may disturb or damage information technology equipment/systems as well as equipment with electronic components or circuits. Chapter 51 – Common rules The requirements concerning the connection of


cables to switchgear in relation to temperature rating have been modified. Orange as a means of identification of an electrical conduit has been deleted. The regulation concerning the warning notice for voltage has been modified. Chapter 52 – Selection and erection of wiring systems Regulation 522.6.101 now permits an exception for a cable forming part of a SELV or PELV circuit. Regulation 522.6.102 now permits an


exception for minor works where the designer is satisfied that there would be minimal increased risk of damage to the circuit cable due to penetration by screws, nails and the like. Regulation 522.6.103 now permits an exception (for the exclusion of additional protection via an RDC) for minor works that do not involve a new partition or a cable passing through a metal part of a partition, where the designer is satisfied that there would be minimal increased risk of damage to the circuit cable due to penetration by screws, nails and the like. Chapter 53 – Protection, isolation, switching, control and monitoring This chapter now includes a new Section 534, which deals with the installation of surge protective devices (SPD). The requirements of Section 534 are for the selection and erection of SPDs for electrical installations of buildings, in order to limit transient overvoltages of atmospheric origin transmitted via the supply distribution system and against switching overvoltages. The requirements are also intended to protect against transient overvoltages caused by direct lightning strikes or lightning strikes in the vicinity of buildings protected by a lightning protection system. Part 6 – Inspection and testing Mainly editorial changes to Chapter 61 and notes


added. Changes have been made to Chapter 63 to take account of the change from periodic inspection report to condition report.


The following new sections are now included in Part 7: Section 710 – Medical locations This section applies to electrical installations in medical locations so as to ensure safety of patients and medical staff. These requirements, in the main, refer to hospitals, private clinics, medical and dental practices, healthcare centres and dedicated medical rooms in the workplace. Section 729 – Operating or maintenance gangways This section applies to restricted areas for authorised persons. These are areas such as switchrooms with switchgear and controlgear assemblies with a need for operating or maintenance gangways. The scope of Section 729 applies to basic protection and other aspects in restricted access areas with switchgear and controlgear assemblies, and gives requirements for operating or maintenance gangways such as the width of gangways and access areas for operational access, emergency access, emergency evacuation and for transport of equipment.


The following main changes have been made within the appendices: Appendix 4 – Current-carrying capacity and voltage drop for cables Now includes rating factors for triple harmonic currents in four-core and five-core cables with four cores carrying current and the voltage drop requirements from Appendix 12.


Appendix 6 – Model forms for certification and reporting Now includes a new electrical installation condition report that replaces the periodic inspection report. The new condition report includes a series of new inspection schedules. Also, the form has been redesigned. Within the observations section, the four codes have been replaced by three codes: Code 1 Danger present, Code 2 Potentially dangerous, Code 3 Improvement recommended.


How much do you know about electric storage heating?


FACT 9


Running on off-peak electricity Dimplex storage heaters will always be cheaper over a 16 hour day than electric convector heaters on the day-rate.


Surprised?


This is just 1 from a long list of little known facts. See them all at www.dimplex.co.uk/facts


Winter 2010 ECA Today 51


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