The list of topics given below is a summary of the additions and changes to the IET, 17th Edition Wiring Regulations BS 7671:2008 (2011) resulting from the 1st Amendment.

New numbering system

• IEC decimal point numbering system to make it easier to embody future changes

Part 2, Definitions

• Definitions have been expanded & the TN & TT system diagrams deleted

Part 1, Assessment of general characteristics

• Now includes the TN & TT system diagrams etc.

Chapter 41, Protection against electric shock

• Now permits an exception to minor works, Regulation 411.3.3

Chapter 44, Protection against voltage disturbances & electromagnetic disturbances

• Modifications & reference to Section 543

Chapter 51, Common rules

• Include a number of changes & requirements concerning cables to switchgear in relation to temperature rating
• Orange as a means of identification of an electrical conduit has been deleted

Chapter 52, Selection and erection of wiring systems

• The use of RCDs under certain circumstances as indicated in this amendment
• Exception for minor works, concerning cables concealed in a wall or partition (at a depth of less than 50mm)
• Reference to skilled or instructed person
• Cables with an earthed metallic covering, earthed conduit/trunking or mechanical protection

Chapter 56, Safety services

• Incorporates editorial changes, updated standards
• Requirements for switching & control gear for use on a.c. & d.c. added

Appendix 3, 4, 5, 11, 12, & 16

• Changes have been made & they will be covered

Appendix 6, Changes to the Periodic Inspection Report

• Model forms for Certificating and Reporting
• Electrical Installation Condition Report (EICR) will replace the current Periodic Inspection Report (PIR)
  4 observation codes will be replaced by 3 observation codes

Section 729, Operating or maintenance gangways
Section 729 is a new section

• Applies to areas such as switch-rooms with switchgear and control gear assemblies
• Need for operating or maintenance gangways for authorised persons
• Sufficient space for the initial inspection of items of electrical equipment
• Sufficient space for the replacement of items of electrical equipment
• Sufficient space for the testing or fault detection, maintenance or repair of items of electrical equipment
• Width, height & lighting of gangways and access areas shall be adequate for work, operational access, emergency access/evacuation and movement of equipment
• Considerations for lighting & signage

Annex A of section 729 closed restricted access areas in order to permit easy evacuation

Section 534, Devices for protection against overvoltage

• Requirements for the installation of Surge Protection Devices (SPD)
• Background & types of SPD
• Choice & type & fitting of SPDs
• Requirement as recommended by Section 443 or by the designer
• Limit transients and overvoltages (varistors)
• Risk assessment considerations & BS EN 62305
• SPD for lightning strikes
• Protection of electrical switchgear
• SPD installation in conjunction with RDSs
• Regulation 534.2.9 conductor lengths
• Regulation 534.2.10 conductor cross-sectional area
• Implication of transients resulting from switching, fault initiation etc.
• Surges present risk of sparking or flashover & potential damage to electrical & electronic equipment, PLC controllers etc.

Section 444, Measures against electromagnetic disturbances

• Electromagnetic Compatibility (EMC) & regulations
• Consideration must be given to the location of the sources of electromagnetic disturbances relative to the positioning of other equipment
• Identifying sources of electromagnetic disturbances such as VSDs etc.
• Section 444.4.2 contains measures to reduce Electromagnetic Interference (EMI)
• The use of SPD & or Filters to reduce EMI
• Separation of power & signal cables

Section 710, Medical Locations

• Medical locations are split into three different groups
• Specific requirements for protection against electric shock
• Specific requirements for IT systems
• Specific requirements for supplementary equipment bonding
• Specific requirements for erection of electrical equipment

BS EN 60204-1 Overview of Control Cabinet Wiring

• Recommendations for control cabinet wiring colours
• Alternative method of wiring identification