• Product Description

    Requirements for Electrical Installation (IET Wiring Regulations) 17th Edition 3rd Amendment

    BS 7671 (The IET Wiring Regulations, 17th Edition) is the national standard to which all UK domestic and industrial wiring must conform. The new standard, BS7671:2008 3rd Amendment, contains extensive changes to align with European documents.

    The IET Wiring Regulations are of interest to all those concerned with the design, installation and maintenance of electric installations in buildings. The market includes electricians, electrical contractors, consultants, local authorities, surveyors and architects. This book will also be of interest to professional engineers, as well as students at university and further education colleges.

    Contents: Scope, object and fundamental principles. Definitions. Assessment of general characteristics. Protection for safety. Selection and erection of equipment. Special installations of locations. Inspection and testing.

    What are the changes?

    New numbering system:
    The 3rd amendment will recognise UK only regulations and these will be identified by a new numbering system. Regulations with a .100 number are CENELEC requirements and those with a .200 number are specific to the UK.

    Part 2, Definitions:
    Definitions will be expanded and modified. The definition of competent persons will be removed. It is likely to be replaced with instructed person (electrically) and skilled person (electrically). These changes will be reflected throughout the wiring regulations.

    Chapter 41, Protection against Electric Shock
    There will be a requirement for RCD protection for socket outlets up to 20A for all installations, with a specific exception for where a documented risk assessment determines that it's not necessary.
    Maximum earth fault loop impedances given in tables 41.2, 41.3, 41.4 and 41.6 have been revised to take account of the Cmin factor. Cmin is the minimum voltage factor to take account of voltage variations that naturally occur in a supply.

    Chapter 52, Selection and Erection of Wiring Systems
    In the light of the very real dangers to fire-fighters, a new regulation 521.200 (UK only) has been included giving requirements for the methods of support of wiring systems in escape routes. The regulations concerning selection and erection of wiring systems have been re-drafted. Reference to under the supervision of a skilled or instructed person has been removed.

    Chapter 51, Common Rules
    Section 551 concerning compliance with standards requires all equipment to be suitable for the nominal voltage and also requires certain information to be noted on the electrical installation certificate.

    Chapter 42, Protection Against Thermal Effects
    Regulation 421.1.200 (UK only) has been added and requires switchgear assemblies including consumer units installed in domestic premises to have their enclosure manufactured from non-combustible material or otherwise suitably installed. The implication of this change will be that most consumer units in domestic premises will be metallic. The implementation of this regulation is expected on 1 January 2016 to allow for manufacturers to ensure adequate supply is available.

    Chapter 55, Other Equipment
    A new section 557 Auxiliary Circuits is included. All auxiliary circuits are defined in Part 2.

    Section 559, Luminaires and Lighting Installation
    Requirements for outdoor lighting installations and extra-low voltage lighting installations have been moved to new sections 714 and 715 respectively.

    Part 7, Special Installations or Locations

    Section 701, Locations Containing a Bath or Shower
    There is a requirement for all low voltage circuits serving or passing through the location to be RCD protected.

    Appendix 3, Time/Current Characteristics of Over Current Protective Devices and RCDs
    This includes changes in connection with maximum earth fault loop impedance to take account of the Cmin factor given in CLC/TR50480: 2011.

    Appendix 6, Model Forms for Certification and Reporting
    The schedule of inspections (for new work only) has been replaced by examples of items requiring inspection during initial verification (which must be appended to the Electrical Installation Certificate). It will also make a small number of changes to the Electrical Installation Condition Report and associated notes, including a requirement to carry out an inspection within an accessible roof space where electrical equipment is present in that roof space.

    Item Specification

    Publication Date 05/01/2015
    Publisher  IET
    ISBN  9781849197694
    Format  Paperback
    Dimensions  21.6x30.5 cm
    Trim Size 297x210mm

    Additional Details

    Author IET
    Industry Electric