Practical Guide to Inspection, Testing and Certification of
Contents
1. Compliance with building regulations is a legal requirement and electrical work carried out in the domestic sector is now included in the building regulations it is a criminal offence not to comply with the building regulations At the time of writing there is no legal requirement to notify any work carried out in commercial or industrial buildings although it should still be certificated for safety and record keeping purposes Approved Document Part P requires that most electrical work carried out in domestic premises is notified to the local authority building control There are a few exceptions but the work must comply with BS 7671 Wiring Regulations The exceptions are as follows e Minor works carried out in areas that are not classed as special locations and therefore do not need notifying but would still need certifying addition of socket outlets and fused spurs to an existing radial or ring circuit addition of a lighting point to an existing circuit installing or upgrading main or supplementary bonding e Minor works carried out in the special locations as listed below orin kitchens BS 7671 does not recognize a kitchen as a special location Part P does kitchens locations containing bath tubs or shower basins hot air saunas electric floor or ceiling heating garden lighting if fixed to a dwelling wall it is not deemed to come into the special location category solar pho2. A qualification is fine but being able to carry out electrical work safely is far better for that reason high quality training is very important
3. Figure 4 21 Lead touching tap 64 Figure 4 22 Lead on unpainted part of radiator 64 Figure 4 23 Fitting bonded across 65 Figure 4 24 Current flow through pipe 65 Figure 4 25 Cables joined 67 List of figures and tables Figure 4 26 Figure 4 27 Figure 4 28 Figure 4 29 Figure 4 30 Figure 4 31 Figure 4 32 Figure 4 33 Figure 4 34 Figure 4 35 Figure 4 36 Figure 4 37 Figure 4 38 Figure 4 39 Figure 4 40 Figure 4 41 Figure 4 42 Figure 4 43 Figure 4 44 Figure 4 45 Figure 4 46 Figure 4 47 Figure 4 48 Figure 4 49 Figure 4 50 Figure 4 51a Figure 4 516 Figure 4 51 c Figure 4 52 Figure 4 53 Figure 4 54 Figure 4 55 Figure 4 56 Figure 4 57 Figure 4 58 Figure 4 59 Figure 4 60 Figure 4 61 Figure 4 62 Figure 4 63 Figure 4 64 Figure 4 65 Figure 4 66 Figure 4 67 Figure 5 1 Figure 5 2 Probes on line and earth Lead connected to earthing terminal Lead touching earthed metal Ring circuit Broken conductor Interconnection Set to ohms Test each end of the line conductor Test each end of the neutral conductor Test each end of the CPC Cross connect live ends Test line to neutral Cross connect line to earth Test line to earth at each socket Cross connect live conductors Conductors in series Conductors in parallel Leads apart Leads together Instruments set Test between live conductors Join live conductors and test to earth Test between live conductors Live conductors tested to earth Test the set Te
4. earth Certificate R R path Measured value Two lead connection Three lead connection Two lead connection Three lead connection Line and earth linked Incoming supply to outgoing line Instrument set Test between incoming line and neutral Measured value Leads connected BS EN 60898 Voltage operated RCD BS 4293 BS 4293 type S Single phase Three phase RCD socket outlet BS EN 61009 1 BS EN 61008 1 type S Set at times half No trip No trip Test at times one Test at 180 Set at times five Test at zero degrees Test at 180 Manual test Test label Minor works certificate Electrical installation certificate 110 113 113 114 114 115 115 116 LET 117 118 118 119 119 124 120 126 127 127 132 132 135 135 136 tof 138 139 139 140 140 140 140 141 141 143 143 143 144 144 145 145 146 146 147 152 155 xiii XIV List of figures and tables Figure 6 3 Figure 6 4 Figure 6 5 Figure 6 6 Figure 8 1 Figure 8 2 Figure 10 1 Figure 10 2 Figure 10 3 Figure 10 4 Figure 10 5 Figure 10 6 Figure 10 7 Figure 10 8 Figure 10 9 Figure 10 10 Figure 10 11 Figure 10 12 Figure 10 13 Figure 10 14 Schedule of test results Schedule of inspections Electrical installation condition report Condition report inspection schedule Test box Calibration register Transformer inverter Inverter without transformer D C identification Dual isolation label Commissioning report Voltage me
5. electrical wiring along with inspection testing and certification very seriously It is important that we not only know how to install all of our new fixed wiring correctly but that we know how to verify and document it as well Not only that We should also be able to inspect an existing installation and with the help of some testing where required we should be able to verify that it is fit for continued safe use Where damage or non conformities are found we must be able to identify them and make sound professional recommendations about the installation Introduction We must also be able to relay this information to our clients in a professional non technical manner Many of us will remember how difficult it was to understand the terms used in the electrical industry when we first started out Your client will need you to identify the technical detail record it and then relay it to them in words which they can understand of course before we can do that we need to understand it ourselves Hopefully what follows in this book will be of help Video footage and multiple choice questions are also available to help you with this subject Visit www routledge com cw kitcher to access this material The legal requirements Apart from the obvious safety reasons we also have to concern ourselves with the legal requirements for electrical installations The main statutory documents which we need to comply with are e The Healt
6. not necessary to attend one of these in order to register as a domestic installer While it may well be beneficial to an electrician who is a bit rusty to attend a refresher course just to ensure that they are aware of the requirements of Part P it is not possible to become an electrician in 5 days You will even see advertised courses with duration of from 15 to 30 days this is really just selling a dream at the end of the period you will have spent a lot of hard earned cash and collected a lot of certificates The one thing which you will not have is experience and that is the most important tool which you could possibly have in your box The building control authorities must be informed of any electrical work that is to be carried out on a domestic electrical installation other than very minor work although even this work must be certificated Building control can be informed before commencing work by the use of a building notice and this will involve a fee If your work involves a lot of domestic electrical work then by far the best route would be to join one of the certification bodies This would allow you to self certificate your own work When you join one of these organizations you must be able to show that your work is up to a satisfactory standard and that you can complete the correct paperwork test certificates Whichever organization you choose to join they will give you the correct advice on which training you require
7. reader is urged to consult with an appropriate licensed professional prior to taking any action or making any interpretation that is within the realm of a licensed professional practice Trademark notice Product or corporate names may be trademarks or registered trademarks and are used only for identification and explanation without intent to infringe First edition published by Newnes 2007 Second edition published by Newnes 2008 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data Kitcher Chris Practical guide to inspection testing and certification of electrical installations Chris Kitcher 3rd ed p cm 1 Buildings Electric equipment Inspection Handbooks manuals etc Title TK4001 K48 2012 621 319 240288 dc23 2011035997 ISBN 13 978 0 08 096907 7 pbk Chapter 1 Chapter 2 Chapter 3 List of figures and tables Acknowledgements Introduction Inspection and testing of electrical installations The legal requirements BS 7671 Building Regulation Part P Section 1 Design installation inspection and testing Section 2 Extensions material alterations and material changes of use Section 3 Information about other legislation Compliance with Building Regulations Part P Earthing and bonding to comply with Part P Registered domestic installer Unregistered competent person DIY
8. 671 Installation certificates This tells us that compliance with Part P can be demonstrated by the issue of the correct electrical installation certificate It also shows what the certificate should cover This is addressed later in this book Practical Guide to Inspection Testing amp Certification of Electrical Installations Building regulation compliance certificates or notices for notifiable work This tells us that the completion certificates issued by the local authorities etc are not the same as the certificates that comply with BS 7671 The completion certificates do not only cover Part P but also shows compliance with all building regulations associated with the work which has been carried out Certification of notifiable work This is covered in detail throughout this book Inspection and testing of non notifiable work This tells us that even if the work is non notifiable it must be carried out to comply with BS 7671 and that certificates should be completed for the work Provision of information Information should be provided for the installation to assist with the correct operation and maintenance This information would comprise certification labels instruction and plans Section 2 Extensions material alterations and material changes of use This section is covered throughout this book It basically tells us that certification is required and that before any additions or alterations are made to an insta
9. Third edition Practical Guide to Inspection Testing and Certification of Electrical Installations Conforms to 17th Edition IET Wiring Regulations Christopher Kitcher Practical Guide to Inspection Testing and Certification of Electrical Installations would like to dedicate this book to all of my grandchildren and thank them for leaving me in peace when asked Inspection Testing and Certification of Electrical Installations Third Edition Christopher Kitcher Third edition published 2013 by Routledge 2 Park Square Milton Park Abingdon Oxon OX14 4RN Simultaneously published in the USA and Canada by Routledge 711 Third Avenue New York NY 10017 Routledge is an imprint of the Taylor amp Francis Group an informa business 2013 Christopher Kitcher The right of Christopher Kitcher to be identified as author of this work has been asserted by him in accordance with sections 77 and 78 of the Copyright Designs and Patents Act 1988 All rights reserved No part of this book may be reprinted or reproduced or utilised in any form or by any electronic mechanical or other means now known or hereafter invented including photocopying and recording or in any information storage or retrieval system without permission in writing from the publishers The publisher and author disclaim any liability in whole or in part arising from information contained in this publication The
10. asurement lIrradiance meter D C clamp meter D C leads joined Current measurement using clamp meter Current measurement using a multimeter D C isolated D C cables linked Insulation test 157 158 Irz 182 198 199 206 206 207 208 209 211 214 214 210 eur 218 219 220 220 Table 4 1 Table 4 2 Table 4 3 Table 5 1 Table 5 2 Table 5 3 Table 7 1 Table 9 1 Table 9 2 Table 10 1 Table 11 1 Table 11 2 Table 11 3 Table 11 4 Recommended tests for further testing Maximum length of copper protective bonding conductor Minimum acceptable resistance values Electrode resistance values Ambient temperature multipliers Examples of rated short circuit capacities for devices Circuit breaker application Table of IP ratings Third letter Panel data sheet Circuit details Circuit details Ring circuit detail Z values 43 54 81 111 12 138 190 204 204 211 220 226 229 231 Central Sussex College for the use of their workshop facilities Simon Wood of Megger UK for help beyond the call of duty Dave Chewter for always being ready to help with anything Inspecting and testing of electrical DEEE at We all use electricity every day and most of us just take it for granted that it is safe to use Of course for the majority of time it is This is not usually down to luck although when I think about some of the installations which have seen over the years am well aware that on some occasions
11. ck 199 Electric shock 201 Ingress protection 203 Testing photovoltaic systems 209 Testing and commissioning 200 Visual inspection 205 Testing the d c side of the installation 208 Insulation resistance test 216 Testing the a c side of the installation 219 Exercises and questions 223 Answers 239 209 269 Figure 1 1 Wind up insulation resistance tester 1 Figure 1 2 Earth fault loop impedance tester 2 Figure 2 1 Minor electrical installation work certificate 16 Figure 2 2 Electrical installation certificate 17 Figure 2 3 Schedule of test results 19 Figure 2 4 Schedule of inspections 20 Figure 3 1 Electrical installation condition report 26 Figure 3 2 Condition report schedule of inspection 28 Figure 4 1 Approved voltage indicator and test lamp 47 Figure 4 2 Warning notices 47 Figure 4 3 Locking devices 48 Figure 4 4 Proving unit 48 Figure 4 5 R RF box 49 Figure 4 6 Test line to neutral 49 Figure 4 7 a Test line to earth 50 Figure 4 7 0 Neutral to earth 50 Figure 4 8 Locked off 51 Figure 4 9a Test line to neutral 92 Figure 4 96 Line to earth 52 Figure 4 9c Neutral to earth 52 Figure 4 10 Retest device 53 Figure 4 11 Double check 90 Figure 4 12 Isolate the supply 99 Figure 4 13 Bonding disconnected 56 Figure 4 14 Low resistance ohm meter oF Figure 4 15 Lead connected o Figure 4 16 Second lead connected 58 Figure 4 17 Resistance value 58 Figure 4 18 Reconnect bonding 59 Figure 4 19 Incorrect 60 Figure 4 20 Correct 60
12. ctrical installation works certificate 191 Part 1 Description of minor works 151 Part 2 Details of the installation T9 Part 3 Essential tests 156 Part 4 Declaration 154 Electrical installation certificate 154 Information required 154 Next inspection 159 Supply characteristics and earthing arrangements 159 Nature of supply parameters 160 Frequency 160 Prospective fault current 160 External earth loop impedance Z 160 Supply protective device 160 Particulars of the installation referred to in the certificate 160 Main protective conductors 161 Main switch or circuit breaker 161 Comments on the existing installation 162 Vill Contents Chapter 7 Schedules Schedule of test results Information required Test results Schedule of inspections Description of items to be checked Basic protection Fault protection Prevention of mutual detrimental influence Identification Cables and conductors General Electrical installation condition report Completing the form Summary on the condition of the installation Recommendations Declaration Schedules Supply characteristics and earthing arrangements Particulars of the installation referred to in the certificate Main protective conductors Main switch switch fuse circuit breaker Observations Condition report inspection schedule Correct selection of protective devices Why are they installed What type of device is it Is it a fuse or circuit breaker Is the device being used for pr
13. e work is in a bathroom or any other areas which may require protective supplementary bonding then this must also be brought up to the current standard There is no requirement to upgrade supplementary bonding in an area where work is not to be carried out There is also no requirement under Part P to certificate the upgrading of any earthing and bonding that has been carried out to an existing installation Registered domestic installer To become a registered domestic installer it is necessary to become a member of one of the certification bodies which operate a domestic installer s scheme This would require the person carrying out the work to prove competence in the type of work which is being carried out and the ability to inspect test and certificate the work which he she has carried out Competence is usually assessed by a site visit from an inspector employed by the chosen scheme provider 11 The legal requirements When the scheme was first introduced there were three types of registration A was for installers who could carry out all types of domestic wiring B for installers who only needed to install single circuits in relation to the type of work which they were doing This could have possibly applied to a kitchen installer or a bathroom fitter Level C was for alterations and minor repairs only This has now changed and there is now one level of registration only and that is full scope which allows anything from a c
14. etent person the required certification must still be completed by the person who carried out or who is responsible for the work DIY installer In cases where the work is carried out by a person who could not be deemed qualified i e a DIY enthusiast building control must be informed prior to work commencing and on completion of the work to the building control officer s satisfaction an inspection and test certificate must be issued As a DIY installer would be unlikely to have the knowledge experience or correct test equipment required Practical Guide to Inspection Testing amp Certification of Electrical Installations to carry out the inspection tests or completion of the certification the services of a competent person would be required The qualified person would in effect take responsibility for the new altered work For that reason the qualified person would need to see the work at various stages of the installation to verify that the work and materials used comply with the required standards of the BS 7671 Wiring Regulations Currently there is no requirement for any person carrying out electrical work in a domestic environment to be qualified in any way The condition is that they must be competent in other words they must be in possession of the appropriate technical Knowledge or experience to enable them to carry out the work safely Many organizations provide what are Known as Part P courses however it is
15. h and Safety at Work Act 1974 HASWA e The Electricity at Work Regulations 1989 EAWR e The Electrical Safety Quality and Continuity Regulations 2002 ESQCR The HASWA 1974 is in place to cover all aspects of safety at work and can be viewed as the statutory document under which the other statutory documents which involve health and safety sit The EAWR 1989 are specific to electrical installations used in the work place although it is sensible for us to refer to them for all installations as this will ensure an electrically safe environment Non compliance with statutory regulations will be seen as a criminal offence and for that reason non compliance could result in a very large fine or even in some serious cases imprisonment particularly where the non compliance has resulted in an accident The ESQCR are intended more for electrical supplies but do have some effect on the daily activities of electricians particularly with regards to the positioning of consumer s units and areas where TNC systems are used As an example where an area is known to be susceptible to flooding all of the supply equipment and consumer s units need to be sited above the expected flood level These statutory regulations not only apply to new installations they also apply to existing installations which have been in use for a very long time There is no age limit on electrical installations the requirement is that they are maintained in a safe conditio
16. hange of switch to a complete rewire or new installation If the electrician is registered as a domestic installer he or she must complete the correct certification and notify the scheme provider with whom they are registered of the work which has been carried out This must be done within 30 days The scheme provider will both notify the local authority and the customer of the correct certification being given An annual fee is usually required by the scheme provider while a small fee is also payable for each job registered Unregistered competent person If the work is carried out by a non registered competent person who is capable of completing the correct certification the local authority will need to be contacted before commencement of the work and the work will be carried out under a building notice This will involve a fee being paid to the local authority and a visit or visits being made by a building inspector to inspect the work being carried out to ensure that it meets the required standard the cost of this will usually be far higher than that charged per notification by a scheme provider to a registered installer On satisfactory completion and after the issue of the correct certification by the competent person the building inspector will issue a completion certificate The issue of a completion certificate by the local authority does not remove the responsibility for the work including guarantees from the non registered comp
17. installer Summary Types of certification required for the inspecting and testing of electrical installations Certification required for domestic installers Part P Minor electrical installation works certificate Part P domestic electrical installation certificate Periodic inspection testing and reporting Certification required for the inspecting and testing of installations other than domestic Minor electrical installation works certificate Electrical installation certificate Initial verification inspection Initial verification testing Sequence of tests Periodic inspection Extent and limitations Visual inspection xi XV Oo on7 10 10 11 11 12 13 13 13 13 14 15 15 19 21 23 23 23 24 25 vi Contents Chapter 4 Chapter 5 What are we looking for during a periodic inspection Three phase circuits systems Periodic testing Voltage drop in conductors Testing of electrical installations Safe isolation Safe isolation procedure Testing of protective bonding conductors Main protective bonding Continuity of protective supplementary bonding conductors Determining if a metal part is extraneous or just a piece of metal Continuity of circuit protective conductors Method 1 Method 2 Ring final circuit test Broken conductor In a ring circuit Interconnections Polarity Insulation resistance test Low Insulation resistance Testing the whole installation Testing of individual circuits Surge protection Ins
18. iously the EAWR 1989 is not only for new installations if anything it is more relevant to existing installations BS 7671 Regulation 621 1 states that where required periodic inspection and testing of every installation shall be carried out in accordance with Regulations 621 2 to 5 in order to determine so far as is reasonably practicable whether the installation is ina satisfactory condition for continued service Although BS 7671 is a non statutory document it has been referred to extensively in the Health and Safety Executive over a long period of time Regulation 114 also clearly states that although BS 7671 is non statutory it may be used in a court of law to claim compliance with a statutory requirement It has been my policy over the years to explain as clearly as possible to my students that although it is non statutory we all do ourselves a big favour by pretending that it is statutory this will ensure that we do the best job possible and that all safety requirements are met Building Regulation Part P The HASWA and EAWR both have the word work in them and of course that reflects that they are intended for use in the work place However electricity is or can be a dangerous commodity wherever it is used It could also be argued that a domestic installation is a The legal requirements place of work while the electrical installation is being carried out This means that the HASWA and EAWR are still relevant Do
19. llation an assessment of the existing installation should be made to ensure that it is safe to add to Section 3 Information about other legislation This covers the Electricity at Work Regulations 1989 Electrical Safety Quality and Continuity Regulations 2002 and functionality requirements The construction design and management regulations also state that adequate electrical inspection and tests are carried out on all new installations those with electrical design information must form a user s manual which can be used to provide an up to date working record of the installation Due to the introduction of Part P even people who are not in the electrical industry are becoming more and more aware that electrical installations need to be safe Insurance companies and mortgage The legal requirements lenders are now frequently asking for certification as part of the house buying and selling process The owners and occupiers of industrial and commercial properties are aware that the EAWR 1989 demand that they maintain a safe environment for people to work in while most licensing authorities and local authorities are asking for electrical certification for most of the work with which they become involved All of these regulations are under the umbrella of the Health and Safety at Work Act 1974 This clearly puts the legal responsibility of health and safety on all persons concerned Compliance with Building Regulations Part P
20. luck must have been around in abundance Over the years the way we deal with electrical installations has changed dramatically this is of course down to education and experience Apart from the use of modern materials and methods of installation we also have improved legislation in place which should ensure that all installations are inspected regularly When first stated full time work back in the early 1960s there were massive house building projects being carried out all over the country but testing and certification of new installations was virtually unheard of When we had completed a new domestic installation the supply authority were really only interested in getting a signature from the person who was going to be expected to pay the electricity bill each quarter We used to do an insulation resistance test on the meter tails and the person who installed the meter usually did the same before connection but that was all The insulation resistance tester was not anywhere near as sophisticated as a modern one we used to have to wind the handle of the instrument as it was a mini generator Figure 1 1 remember clearly that if for some reason we had a fault due to a nail being driven through a cable or some other fault which resulted in a bad reading we would just remove the fuse wire from the rewirable fuses or disconnect the neutral of the circuit concerned before the person arrived to install the meter That way we could be su
21. mestic installations have been the subject of much discussion over the years mainly due to the upsurge in DIY We all know that it is reasonably easy to get something working making sure it is safe is often far more difficult To try and get some kind of control over this the Building Regulation Part P was introduced and came into effect on 1 January 2005 it was then amended on 5 April 2006 The purpose of this document is to ensure electrical safety in domestic electrical installations Section 1 Design installation inspection and testing This section of Part P is broken down into sub sections General This states that electrical work must comply with the Electricity at Work Regulations 1989 and that any installation or alteration to the main supply must be agreed with the electricity distributor Design and installation This tells us that the work should comply with BS 7671 Electrical Wiring Regulations Protection against flooding The distributor must install the supply cut out in a safe place and take into account the risk of flooding Compliance with the Electrical Safety Quality and Continuity Regulations 2002 is required Accessibility Part M of the building regulations must be complied with Inspection and testing before putting into service This area is covered in detail throughout this book it reminds us that the installation must be inspected and tested to verify that it is safe to put into service BS 7
22. n and that they remain fit for use Practical Guide to Inspection Testing and Certification of Electrical Installations 978 0 08 096907 7 Copyright 2013 Christopher Kitcher Published by Taylor amp Francis All rights reserved Practical Guide to Inspection Testing amp Certification of Electrical Installations BS 7671 The most satisfactory way of ensuring conformance with statutory regulations is to follow the requirements of the relevant British Standard The British Standard relating to an electrical installation is Known as BS 7671 Within this set of standards Regulation 610 1 states every installation shall during erection and on completion before being put into service be inspected and tested to verify so far as reasonably practicable that the requirements of the regulations have been met This regulation of course applies not only to new installations it also applies to additions and alterations to existing installations The inspection and testing of new work is known as initial verification As the regulation suggests this initial verification commences at the same time as the installation work continues and carries on through the duration of the job The end result will be the issue of an electrical installation certificate along with the required schedule of test results and a schedule of inspections providing of course the work carried out fully meets the requirement of BS 7671 As we have seen prev
23. otection against Indirect contact What type of circuit is the device protecting is it supplying fixed equioment only or could it supply hand held equioment If it is a circuit breaker is it the correct type Will the device be able to safely interrupt the prospective fault current which could flow in the event of a fault Is the device correctly coordinated with the load and the cable Additional information regarding circuit breakers Overload current Maximum earth fault loop impedance values Z for circuit breakers 162 162 163 164 165 165 166 166 168 168 169 170 171 1 795 17G 176 Vid 1 Lee 179 1 180 180 181 185 185 186 18 187 187 188 188 188 188 188 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Glossary Index Calculation of the maximum A of circuit Contents breakers 189 Comparing maximum Z and measured 4 190 Testing transformers 191 Step up or down double wound transformer 191 Isolation transformer 192 Separated extra low voltage transformers SELV and PEL 192 Testing a 3 phase motor 192 Test equipment 195 Instruments required 195 Low resistance ohm meter 195 Insulation resistance tester 196 Earth fault loop impedance tester 196 Prospective short circuit current test Instrument 196 Earth electrode resistance tester 196 Residual current device tester 197 Phase rotation 197 Thermographic equioment 197 Calibration of test instruments 197 Volt sti
24. re that the installation would be connected and that we would have an electrical supply It is usually easier to trace a fault if the system is live particularly in the winter as it is much easier to find a fault in a warm house with light than a cold house in the dark As far as earth fault loop impedance was concerned the only time we measured that was when a survey was being carried out and again Figure 1 1 Wind up insulation resistance tester Introduction Figure 1 2 Earth fault loop impedance tester the instrument was entirely different to the equipment used today Figure 1 2 All new houses had a copper or iron water main as did most old ones As you can imagine the surface area of the metal from the water mains in contact with the soil was huge This resulted in very low earth fault loop resistance readings This is because the resistance of soil is usually very low as there is such a lot of it As the years have passed more and more electrical equipment is being installed into buildings it is also becoming more and more sophisticated of course Health and safety along with insurance has also had a hand in making it important that in the event of a fault somebody can be held responsible Usually this will be the person signing the document to say that the installation is compliant with the current edition of the wiring regulations BS 7671 For this reason it is very important that we take the installation of
25. st L2 to L3 Test L1 to L3 Test L1 to L2 Link L1 L2 and L3 Test line to earth Line and CPC connected Test between line and earth R R High reading Line linked to earth terminal Test between earth and switched line Low reading High reading Line and earth terminal linked Test at switch Low resistance measure High reading Live supply Live supply No reading Earth electrode tester Electrodes in the ground 68 69 70 71 t2 13 74 14 15 15 10 70 tf 18 T9 80 80 83 83 85 86 8 90 90 91 92 93 93 94 94 97 97 98 98 99 99 100 101 101 102 102 103 104 104 106 107 Figure 5 3 Figure 5 4 Figure 5 5 Figure 5 6 Figure 5 7 Figure 5 8 Figure 5 9 Figure 5 10 Figure 5 11 Figure 5 12 Figure 5 13 Figure 5 14 Figure 5 15 Figure 5 16 Figure 5 17 Figure 5 18 Figure 5 19 Figure 5 20 Figure 5 21 Figure 5 22 Figure 5 23 Figure 5 24 Figure 5 25 Figure 5 26 Figure 5 27 Figure 5 28 Figure 5 29 Figure 5 30 Figure 5 31 Figure 5 32 Figure 5 33 Figure 5 34 Figure 5 35 Figure 5 36 Figure 5 37 Figure 5 38 Figure 5 39 Figure 5 40 Figure 5 41 Figure 5 42 Figure 5 43 Figure 5 44 Figure 5 45 Figure 5 46 Figure 6 1 Figure 6 2 List of figures and tables Tester connected TT service head TT fault path TN S service head TN S fault path TN C S service head TN C S fault path Isolated Disconnected earthing conductor Test instrument Line to earth Line to neutral and
26. tovoltaic power supply systems 10 Practical Guide to Inspection Testing amp Certification of Electrical Installations e The work which could be carried out in these locations without notification but should still be certificated would be e Replacement of a single circuit which has been damaged providing that the circuit follows the same route the cable used has the same current carrying capacity as the cable being replaced circuit protective measures are not affected e Replacing accessories such as socket outlets switches and ceiling roses e Re fixing or replacing of enclosures and components All other work carried out in any areas of a domestic installation must be certificated and notified to the local authority building control this can be carried out by various methods Earthing and bonding to comply with Part P If a minor electrical installation works certificate is necessary there is no requirement to upgrade the existing earthing and bonding arrangements within an installation Where the earthing and bonding do not comply with the latest edition of BS 7671 it should be recorded on the minor electrical installation works certificate and brought to the responsible person s or occupier s attention If the work being carried out requires an electrical installation certificate to be completed then the earthing arrangements must be upgraded to comply with the current edition of BS 7671 Where th
27. ulation resistance testing of a 3 phase Installation Polarity test Polarity test on a radial circuit Such as a cooker or immersion heater circuit Polarity test on a lighting circuit Live polarity Earth electrode testing Measurement using an earth electrode tester Performing the test Testing with an earth loop resistance tester Earth fault path for a TT system Earth fault path for a TN S system Earth fault path for a TN C S system Performing a Z test Circuit earth fault loop impedance Z Verification of Z values Method using tables from GNS or the On site Guide 35 39 41 44 46 46 49 53 53 61 66 66 6 69 O a a2 l2 80 81 62 88 89 91 96 96 9 103 105 105 105 109 iz Liz TZ 112 114 119 123 Contents Vil Direct measurement S A circuit incorporating a socket outlet on a ring or a radial 124 Performing the test on a radial circuit other than a socket outlet 124 Earth loop impedance using a high current loop test instrument without tripping an RCD To Prospective fault current test I 183 Enquiry 1883 Calculation 134 Measurement 134 Three wire text 136 Functional testing 138 Residual current device 188 Types of RCD 139 RCDs and supply systems 141 Testing of RCDs 141 Voltage operated ELCBs 141 BS 4293 RCDs 142 BS EN 610081 14 BS 4298 type S 147 BS EN 61008 type S 148 BS 7288 RCD protected socket 148 BS EN 61009 RCBOs 148 Chapter 6 Completion of test certificates 151 Minor ele
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