Contents

1 - The IEE Regulations, BS 7671, and this Guide
      1.1 - The need for this Electricians Guide
      1.2 - The IEE Regulations
            1.2.1 International basis
            1.2.2 The Sixteenth Edition
            1.2.3 Plan of the Sixteenth Edition

2 - Installation requirements and characteristics
      2.1 - Introduction
      2.2 - Safety requirements
            2.2.1 Scope of the Regulations
            2.2.2 Legal status of the Regulations
            2.2.3 New inventions and methods
            2.2.4 Safety Requirements
            2.2.5 Supplies for safety services
      2.3 - Definitions
      2.4 - Assessment of general characteristics
            2.4.1 Introduction
            2.4.2 Purposes, supplies and structure
            2.4.3 External influences
            2.4.4 Compatibility
            2.4.5 Maintainability
      2.5 - Low voltage generating sets
      2.6 - Standards
      2.7 - Undervoltage

3 - Installation control and protection
      3.1 - Introduction
      3.2 - Switching
            3.2.1 Switch positions
            3.2.2 Emergency switching
            3.2.3 Switching for mechanical maintenance
            3.2.4 Functional switching
      3.3 - Isolation
            3.3.1 Isolator definition
            3.3.2 Isolator situation
            3.3.3 Isolator positions
            3.3.4 Semiconductor isolators
            3.3.5 Isolator identification
      3.4 - Electric shock protection
            3.4.1 The nature of electric shock
            3.4.2 Resistance of the shock path
            3.4.3 Contact with live conductors
            3.4.4 Protection from contact
            3.4.5 Direct contact protection
            3.4.6 Indirect contact protection
            3.4.7 Protection for users of equipment outdoors
      3.5 - High temperature protection
            3.5.1 Introduction
            3.5.2 Fire protection
            3.5.3 Protection from burns
      3.6 - Overcurrent protection
            3.6.1Introduction
            3.6.2 Overload
            3.6.3 Fuses
            3.6.4 Circuit breakers
            3.6.5 Protecting conductors
      3.7 - Protection from faults
            3.7.1 Introduction
            3.7.2 Prospective short-circuit (PSC)
            3.7.3 Operating time
            3.7.4 Conductors of reduced current-carrying capacity
            3.7.5 Back-up protection
            3.7.6 Insulation monitoring
      3.8 - Short circuit and overload protection
            3.8.1 Combined protection
            3.8.2 Current limited by supply characteristic
            3.8.3 Protection omitted
            3.8.4 Protection of conductors in parallel
            3.8.5 Absence of protection
            3.8.6 Discrimination

4 - Cables, conduits and trunking
      4.1- Introduction
            4.1.1Cable insulation materials
      4.2 - Cables
            4.2.1 Non-flexible low voltage cables
            4.2.2 Cables for overhead lines
            4.2.3 Flexible low voltage cables and cords
            4.2.4 Cables carrying alternating currents
            4.2.5 Corrosion
      4.3 - Cable choice
            4.3.1 Cable types
            4.3.2 Current carrying capacity of conductors
            4.3.3 Methods of cable installation
            4.3.4 Ambient temperature correction factors
            4.3.5 Cable grouping correction factors
            4.3.6 Thermal insulation correction factors
            4.3.7 When a number of correction factors applies
            4.3.8 Protection by semi-enclosed (rewirable) fuses
            4.3.9 Cable rating calculation
            4.3.10 Special formulas for grouping factor calculation
            4.3.11 Cable volt drop
            4.3.12 Harmonic currents and neutral conductors
            4.3.13 Low smoke-emitting cables
            4.3.14 The effects of animals, plants & insects
      4.4 - Cable supports, joints and terminations
         -- 4.4.1 Cable supports and protection
            4.4.2 Cable bends
            4.4.3 Joints and terminations
      4.5 - Cable Enclosures
            4.5.1 Plastic and metal conduits
            4.5.2 Ducting and trunking
            4.5.3 Cable capacity
      4.6 - Conductor and cable identification
            4.6.1 Conduits
            4.6.2 Identification of fixed wiring conductors
            4.6.3 Colours for flexible cables and cords

5 - Earthing
      5.1 - The earthing principle
            5.1.1 What is earthing
            5.1.2 The advantage of earthing
            5.1.3 The disadvantages of earthing
      5.2 - Earthing systems
            5.2.1 System classification
            5.2.2 TT Systems
            5.2.3 TN-S System
            5.2.4 TN-C-S system
            5.2.5 TN-C system
            5.2.6 IT System
      5.3 - Earth-fault loop impedance
            5.3.1 Principle
            5.3.2 The importance of loop impedance
            5.3.3 The resistance-impedance relationship
            5.3.4 Earth-fault loop impedance values
            5.3.5 Protective conductor impedance
            5.3.6 Maximum circuit conductor length
      5.4 - Protective conductors
            5.4.1 Earthing conductors
            5.4.2 Protective conductor types
            5.4.3 Bonding conductors
            5.4.4 Protective conductor cross-section assessment
            5.4.5 Protective conductor cross-section calculation
            5.4.6 Unearthed metalwork
      5.5 - Earth electrodes
            5.5.1 Why must we have earth electrodes
            5.5.2 Earth electrode types
      5.6 - Protective multiple earthing(PME)
            5.6.1 What is protective multiple earthing
            5.6.2 Increased fire risk
            5.6.3 Broken neutral conductor
            5.6.4 Special requirements PME-fed installations