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Amendment 1 BS 7671: 2008


Requirements for Electrical Installations, IET Wiring Regulations (17th Edition)


HIGHLIGHTS AND CHANGES


Points to note: n BS 7671 Amendment 1 was published on 1 July 2011, and comes into force on 1 January 2012.


n From 30 June 2011 to 31 December 2011, designers and contractors have the choice to work to the existing standard or the newly implemented Amendment 1, but not both.


n Clarify with the person ordering the work which edition they want you to design/work to.


n The edition to which you have designed or are installing to should clearly be recorded on the Installation Certificate.


n All installations designed and installed after 31 December 2011 should comply with BS 7671 17th Edition Amendment 1.


The majority of the changes reflect harmonisation with International IEC


60364 and European CENELEC HD 60384 series of standards. The changes are amendments to the current regulations, which is not the same as a new edition of the IET Wiring Regulations being issued. This means that your current 17th Edition qualifications are still valid, although for all assessments after 1 January 2012 you will be required to hold a copy of the new BS 7671 Requirements for Electrical Installations.


BS 7671 Amendment 1 overview There are still seven parts: Part 1: Scope, object and fundamental principles. Part 2: Definitions. Part 3: Assessment of general characteristics. Part 4: Protection for safety. Part 5: Selection and erection of equipment. Part 6: Inspection and testing. Part 7: Special installations or locations, with two new areas introduced (710 and 729). Appendices: There are now 16 Appendices (previously there were 15).


There is a new numbering system to reference UK-only national regulations. Regulations that end in 100, 101, 102, and so on, signify standards that only apply in the UK. Example: Reg 433.1.5 now 433.1.103


There are now 16 Appendices


The new Appendix 16 references devices for protection against overvoltage. Content from Appendices 11 and 12 have moved into Appendix 4, leaving Appendices 11 and 12 blank for future use.


62 ECA Today September 2011


Things that did not change There was a lot of discussion in the industry about draft proposals that did not make the final copy. For example, there was some debate around whether RCD protection for minor works could be omitted, but this has not been implemented. RCD protection is still required for alterations and additions to existing circuits when not under the supervision of skilled or instructed persons.


Main changes Part 1: Changes are mainly editorial in nature. Part 2: Definitions are now given for: n Minor works. n Medical locations. n Operating and maintenance gangways.


Part 3: Changes are mainly editorial in nature. Note that the diagrams for the three earthing systems (TN-S, TN-C-S and TT) have been moved into Part 3. Part 4: There are changes to tables 41.2 and 41.4 due to new fuse standards being introduced:


Was


BS 1361 BS 88-2-2 BS 88-2-6


Now


BS 88-3 BS 88-2 BS 88-2


The effects of these changes are: n Some Zs values are different. n Withdrawal of certain protective device ratings, i.e. 15A devices. n Some time current tables in Appendices are altered.


There is a new Section 444 for measures against electromagnetic disturbances. It has been introduced to help designers and installers meet the EU Directive that was introduced in July 2007 for fixed installations. The other main change in Part 4 is regulation 443.1.1, which highlights Section 534 with reference to Surge Protection Devices (SPDs).


Part 5: As well as editorial changes, there is a new section (534) on Surge Protection Devices (SPDs). An SPD is a device that is intended to limit transient overvoltages and divert surge currents. This section has been introduced because of HD 60364-5-53. Generally,


there is now more sensitive electronic equipment in use so surge protection is becoming more of an issue. In addition, BS EN 62305 (the lightning protection standard) now requires this to be a consideration. Section 534 needs to be read fully in conjunction with Section 443 and table 44.3. Three types of SPDs are recognised:


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