IET Wiring Regulations Explained and Illustrated

Author of IET Wiring Regulations Explained and Illustrated

Brian Scaddan

Brian Scaddan, I Eng, MIET, is an Honorary Member of Metropolis & Guilds and has over 45 years’ expertise in additional training and coaching.

He was Director of Brian Scaddan Associates Ltd, an permitted coaching middle providing programs on all points {of electrical} set up contracting, together with these for Metropolis & Guilds and EAL. He’s additionally a number one creator of books on different set up matters.

IET Wiring Contents

• Chapter 1 elementary necessities for security 
• Chapter 2 earthing
• Chapter 3 safety
• Chapter 4 isolation switching and management 
• Chapter 5 circuit design
• Chapter 6 Inspection and testing
• Chapter 7 particular places IET laws half 7

Preface to IET Wiring Regulations Explained and Illustrated

Because of a few years growing and educating programs dedicated to compliance with the IET Wiring Regulations

It has turn into obvious to me that many operatives and personnel within the electrical contracting trade have forgotten the fundamental ideas and ideas upon which electrical energy provide and its use are primarily based.

Because of this, misconceived concepts and a lot confusion have arisen over the interpretation of the Regulations. It’s the intention of this guide to dispel such misconceptions and to teach and the place crucial refresh the reminiscence of the reader.

On this respect, the emphasis has been positioned on these areas the place most confusion arises, specifically earthing and bonding, safety, and circuit design.

The present eighteenth version of the IET Wiring Regulations, also called BS 7671, to which this guide conforms, was printed in July 2018. This guide isn’t a information to the Regulations or a substitute for them; nor does it search to interpret them Regulation by Regulation.

It ought to, in reality, be learn at the side of them. To assist the reader, every chapter cites the related Regulation numbers for cross-reference.

It’s hoped that the guide shall be discovered significantly helpful by faculty college students, electricians and technicians, and additionally by managers of smaller electrical contracting corporations that don’t usually make use of engineers or designers.

It must also be a helpful addition to the library of these finding out for the Metropolis & Guilds and EAL 18th Version {qualifications}.

Introduction to IET Wiring Regulations Explained and Illustrated

It was as soon as stated, by whom I don’t know, that ‘guidelines and laws are for the steering of clever males and the blind obedience of fools’. That is actually true within the case of the IET Wiring (BS 7671) Regulations.

They don’t seem to be statutory guidelines, however suggestions for the protected choice and erection of wiring installations. Earlier editions have been handled as an ‘electrician’s Bible’: the Regulations now take the shape primarily of a design doc.

The IET Wiring Regulations are divided into seven components. These comply with a logical sample from the fundamental necessities to inspection and testing of set up and lastly to the necessities for particular places:

Half 1 signifies the vary and sort of installations coated by the Regulations, what they’re supposed for, and the fundamental necessities for security.

Half 2 is dedicated to the definitions of the phrases used all through the Regulations.

Half 3 particulars the final info wanted and the basic ideas to be adopted earlier than any design work can usefully proceed.

Half 4 informs the designer of the totally different strategies obtainable for defense in opposition to electrical shock, overcurrent, and so on., and the right way to apply these strategies.

Half 5 allows the right sort of kit, cable, accent, and so on. to be chosen and erected in accordance with the necessities of Elements 1–4.

Half 6 supplies particulars of the related assessments to be carried out on a accomplished set up earlier than it’s energized.

Half 7 offers with specific necessities for particular installations and places akin to loos, swimming swimming pools, building websites, and so on.

Appendices. These present tabulated and different background info required by the designer/installer/tester.

It have to be remembered that the Regulations aren’t a group of unrelated statements every to be interpreted in isolation; there are numerous cross-references all through which can render such an interpretation worthless.

In utilizing the Regulations I’ve discovered the index a useful beginning place when looking for info.

Nonetheless, one might need to attempt totally different mixtures of wording with the intention to find a selected merchandise.

For instance, figuring out how typically an RCD ought to be examined through its take a look at button might show troublesome since no reference is made below ‘Residual present gadgets’ or ‘Testing’

Nonetheless, ‘Periodic testing’ results in Regulation 514.12, and the knowledge in query is present in 514.12.2. Within the index, this Regulation as referred to below ‘Notices’.

Table of contents :

CHAPTER 1 Fundamental Requirements for Safety
IET Wiring Regulations (IET Regulations Part 1 and Chapter 13)
The Health and Safety at Work Act 1974
The Electricity at Work Regulations 1989
The Building Regulations 2010 Part ‘P’

CHAPTER 2 Earthing
Earth: What Is It, and Why and How Do We Connect to It?
Earth Electrode Resistance
Earthing in the IET Regulations (IET Regulations Chapter 4, Section 411)
Earthing Systems (IET Regulations Definitions (Systems))
Earth Fault Loop Impedance
Determining the Value of Total Loop Impedance

CHAPTER 3 Protection
What is Protection?
Protection Against Electric Shock (IET Regulations Chapter 41)
SELV or PELV
Protection Against Overcurrent (IET Regulations Chapter 43 and Definitions)
Protection Against Overvoltage (IET Regulations Section 443)
Protection Against Undervoltage (IET Regulations Section 445)

CHAPTER 4 Isolation Switching and Control
Isolation and Switching (IET Regulations Section 537)

CHAPTER 5 Circuit Design
Design Procedure
Design Current
Nominal Setting of Protection
Voltage Drop (IET Regulations 525 and Appendix 12)
Shock Risk (IET Regulations Section 411)
Thermal Constraints (IET Regulations Section 543)
Example of Use of the Adiabatic Equation
An Example of Circuit Design
Assessment of General Characteristics
Sizing the Main Tails
Sizing the Kiln Circuit Cable

CHAPTER 6 Inspection and Testing
Testing Sequence (Part 7)

CHAPTER 7 Special Locations IET Regulations Part 7
Introduction
BS 7671 Section 701: Bathrooms, etc.
BS 7671 Section 702: Swimming Pools
BS 7671 Section 703: Hot Air Saunas
BS 7671 Section 704: Construction Sites
BS 7671 Section 705: Agricultural and Horticultural Locations
BS 7671 Section 706: Conductive Locations with Restrictive Movement
BS 7671 Section 708: Caravan and Camping Parks
BS 7671 Section 709: Marinas
BS 7671 Section 710: Medical Locations
BS 7671 Section 711: Exhibitions, Shows and Stands
BS 7671 Section 712: Solar Photovoltaic (PV) Supply Systems
BS 7671 Section 714: Outdoor Lighting Installations
BS 7671 Section 715: Extra Low Voltage Lighting Installations
BS 7671 Section 717: Mobile or Transportable Units
BS 7671 Section 721: Caravans and Motor Caravans
BS 7671 Section 722: Electric Vehicle Charging Installations
BS 7671 Section 729: Operating and Maintenance Gangways
BS 7671 Section 740: Amusement Devices, Fairgrounds, Circuses, etc.
BS 7671 Section 753: Floor and Ceiling Heating Systems

APPENDIX A 17th Edition: Examination Question Allocation and Sample Paper
Typical City & Guilds Style Multiple Choice Question Paper
Sample Paper
APPENDIX B Answers to Multiple Choice Test

Download IET Wiring Regulations Explained and Illustrated 11th Version in PDF Format For Free.