Volume II: AC & DC Machines Volume IV: Electronic Devices & Circuits of topics in ''Basic BASIC ELECTRICAL AND ELECTRONICS ENGINEERING BASIC. Basic Electrical Installation Work Everything needed to pass the first part of the City & Guilds Diploma in Electrical Installations. Updated in line with the 3rd . The 5th Edition of Basic Electrical Installation Work has been completely rewritten This book of electrical installation theory and practice will be of value to the.
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Basic Electrical Installation Work has helped thousands of students to gain their first qualification in electrical installation. Now in its fourth edition, this book has. Installation Work This page intentionally left blank. Basic Electrical Installation Work Fourth Edition. TREVOR LINSLEY Senior Lecturer Blackpool and The Fylde. Basic Electrical Installation Work PDF electrical installation work book by brian scaddan Releted Results: advanced electrical installation work edition pdf .
There is probably one bulb out somewhere in the hundreds that you hung up. More than likely it is because one of the lights decided to break or burn out and because they are wired in series the rest are now out as well. Since all of the lights are in-line with each other, if one goes out it causes an open circuit at that point. No current will flow to the other lights because of the open circuit path. Fortunately, a lot of the new light strands are wired in parallel.
Therefore if one light goes out, then only that branch of the circuit will be out. The open will be isolated to that branch and current will continue to the other lights in the strand, Joy…to… the…World! R1 represents the resistance value of the speaker and R2 shows the resistance value of the LEDs.
What is the voltage supplied to the LEDs and to the speaker? First, we need to find the current in the loop once the belly is pressed and switch 1 S1 closes. The supply offers 5 amps of current but the circuit will only use what is demanded by the loads. This circuit is known as a voltage divider circuit. The supply voltage was divided among the loads in proportion to the resistance each load carries. This law states that the algebraic sum of the voltages in a closed loop is always equal to zero.
If we only knew the supply potential and the voltage drop of R1, we could use KVL to find the other voltage drop. With KVL you have to follow the current path and use the polarities of the components shown.
If current path is unknown you have to assume one. We will use the positive to negative clockwise path. KVL really comes in handy when there are multiple supplies in a loop or multiple loops. As mentioned previously, with parallel circuits the voltage across each branch will be equal to the supply voltage. First we need to find the total resistance in the circuit. In series circuits we would just add all of the resistance values together.
In parallel, you have to add the reciprocals of all the resistance values together and then reciprocate back. High fives all around! One quick note, current will always try to take the path of least resistance.
I was taught to think that current flows much the same as water. If you have two channels in a river and one is partially blocked by logs, then most of the water will flow through the clear channel. Same is true with current. In a parallel circuit, the branch with the least amount of blockage or resistance will receive the majority of the current. In our example both channels are partially blocked but the one that is most clear R2 will receive the most current.
Pop Quiz, what if R2 was to short out?
Well, in a short there is no resistance, so all of the current would flow though that branch. The wire could overheat causing the worm to lose its glow and quite possibly everything else. This law basically states that current into a node will equal the current out of the node.
P is for power measured in Watts, I is for current and the E is for voltage. Using the previous parallel example, we can find the power consumed by the circuit.
Conclusion I hope this information helps to refresh that which may have been forgotten. For this rea- and Guilds Level 2 Certificate in Electrotechni- son multiple-choice questions can be found at the end cal Technology and the City and Guilds Level 2 of each chapter. The as an aid to private study and to encourage a thorough book meets the combined requirements of these knowledge of the subject.
Modern regulations place a greater responsibility I would also like to thank my colleagues and stu- upon the installing electrician for safety and the design dents at Blackpool and The Fylde College for their of an installation.
The latest regulations governing suggestions and assistance during the preparation of electrical installations are the 16th edition of the IEE this book. Wiring Regulations BS The fourth edi- Finally, I would like to thank Joyce, Samantha and tion of this book has been revised and updated to incor- Victoria for their support and encouragement. Trevor Linsley This page intentionally left blank To Joyce, Samantha and Victoria This page intentionally left blank 1 Safety regulations and laws Health, safety and welfare legislation has increased the awareness of everyone to the risks involved in the work- place.
All statutes within the Acts of Parliament must be At the beginning of the nineteenth century children obeyed and, therefore, we all need an understanding of formed a large part of the working population of Great the laws as they apply to our electrotechnical industry.
They started work early in their lives and they worked long hours for unscrupulous employers or masters. Statutory cing apprentice working hours to twelve per day and Regulations have been passed by Parliament and have, improving the conditions of their employment.
The therefore, become laws.
Non-compliance with the laws Factories Act of restricted the working week for of this land may lead to prosecution by the Courts and children aged 13 to 18 years to sixty-nine hours in any possible imprisonment for offenders.
We shall now look at three Statutory Regulations as With the introduction of the Factories Act of , they apply to the electrotechnical industry.
They were allowed to employ a small number tricity, Safety, Quality and Continuity Regulations of assistants and were given the responsibility of inspect- formerly Electricity Supply Regulations , ing factories throughout England, Scotland, Ireland and and the Electricity at Work Regulations This small, overworked band of men, were the forerunners of the modern HSE Inspectorate, enforcing the safety laws passed by Parliament. As the years pro- gressed, new Acts of Parliament increased the powers of The Health and Safety at Work the Inspectorate and the growing strength of the Trade Unions meant that employers were increasingly being Act pressed to improve health, safety and welfare at work.
The most important recent piece of health and Many governments have passed laws aimed at improv- safety law was passed by Parliament in called the ing safety at work but the most important recent legis- Health and Safety at Work Act. This Law not only for stimulating and encouraging high standards of increased the employers liability for safety measures but health and safety at work; the Act puts the responsibility also put the responsibility for safety on employees too.
To do this ment, material or substance likely to cause immedi- he must ensure that: ate serious injury; 6 issue an improvement notice which will require an the working conditions and standard of hygiene are employer to put right, within a specified period of appropriate; time, a minor infringement of the legislation; the plant, tools and equipment are properly 7 issue a prohibition notice which will require an maintained; employer to stop immediately any activity likely to the necessary safety equipment such as personal result in serious injury, and which will be enforced protective equipment, dust and fume extractors and until the situation is corrected; machine guards is available and properly used; 8 prosecute all persons who fail to comply with their the workers are trained to use equipment and plant safety duties, including employers, employees, design- safely.
Employees have a duty to care for their own health and safety and that of others who may be affected by their actions Section 7 of the Act. Part 1, Section 3 of the Act instructs not interfere with or misuse anything provided to all employers to prepare a written health and safety protect their health and safety. Figure 1. Your employer must let you or both. This is a large laminated poster, mm suit- Laws and rules must be enforced if they are to be able for wall or notice board display.
The system of control under the Health and All workplaces employing five or more people must Safety at Work Act comes from the Health and Safety display the type of poster shown in Fig.
The HSE is divided into a number of specialist To promote adequate health and safety measures the inspectorates or sections which operate from local employer must consult with the employees safety rep- offices throughout the UK.
From the local offices the resentatives. In companies which employ more than inspectors visit individual places of work. The safety officer is usually employed 1 enter premises unannounced and carry out investi- full-time in that role.
Small companies might employ gations, take measurements or photographs; a safety supervisor, who will have other duties within 2 take statements from individuals; the company, or alternatively they could join a safety 3 check the records and documents required by group.
The safety group then shares the cost of employ- legislation; ing a safety adviser or safety officer, who visits each 4 give information and advice to an employee or company in rotation. It is the intention that all the Companys affairs will be conducted in a manner which will not cause risk to the health and safety of its members, employees or the general public.
For this purpose it is the Company policy that the responsibility for health and safety at work will be divided between all the employees and the Company in the manner outlined below.
Companys responsibilities The Company will, as a responsible employer, make every endeavour to meet its legal obligations under the Health and Safety at Work Act to ensure the health and safety of its employees and the general public. Particular attention will be paid to the provision of the following: 1 Plant equipment and systems of work that are safe. Note: Reference should be made to the appropriate safety etc. Management and Supervisors responsibilities Management and supervisors at all levels are expected to set an example in safe behaviour and maintain a constant and continuing interest in employee safety, in particular by: 1 acquiring the knowledge of health and safety regulations and codes of practice necessary to ensure the safety of emp- loyees in the workplace, 2 acquainting employees with these regulations on codes of practice and giving guidance on safety matters, 3 ensuring that employees act on instructions and advice given.
General Managers are ultimately responsible to the Company for the rectification or reporting of any safety hazard which is brought to their attention.
Joint consultations Joint consultation on health and safety matters is important. The Company will agree with its staff, or their representatives, adequate arrangements for joint consultation on measures for promoting safety and health at work, and make and maintain satisfactory arrangements for the participation of their employees in the development and supervision of such measures.
Trade Union representatives will initially be regarded as undertaking the role of Safety Representatives envisaged in the Health and Safety at Work Act. These representatives share a responsibility with management to ensure the health and safety of their members and are responsible for drawing the attention of management to any shortcomings in the Companys health and safety arrangements.
The Company will in so far as is reasonably practicable provide representatives with facil- ities and training in order that they may carry out this task. Review A review, addition or modification of this statement may be made at any time and may be supplemented as appropriate by fur- ther statements relating to the work of particular departments and in accordance with any new regulations or codes of practice.
This policy statement will be brought to the attention of all employees. They are designed to ensure a proper and safe supply of electrical energy up to the consumers terminals. These regulations impose requirements upon the regional electricity companies regarding the installation and use of electric lines and equipment. The regula- tions are administered by the Engineering Inspectorate of the Electricity Division of the Department of Energy and will not normally concern the electrical contractor except that it is these regulations which lay down the earthing requirement of the electrical supply at the meter position.
The regional electricity companies must declare the supply voltage and maintain its value between prescribed limits or tolerances. The government agreed on 1 January that the electricity supplies in the United Kingdom would be harmonized with those of the rest of Europe. Thus the voltages used previously in low-voltage supply systems of V and V have become V for three- phase supplies and V for single-phase supplies.
The safety representative should The frequency is maintained at an average value of then bring the dangerous situation to the notice of the 50 Hz over 24 hours so that electric clocks remain safety committee for action which will remove the dan- accurate. This may mean changing company policy or pro- Regulation 29 gives the area boards the power to cedures or making modifications to equipment. All refuse to connect a supply to an installation which in actions of the safety committee should be documented their opinion is not constructed, installed and pro- and recorded as evidence that the company takes tected to an appropriately high standard.
This regula- seriously its health and safety policy.
They are statutory regulations and enforced by the Health and Safety Executive. Every work activity shall be carried out We will now look at six non-statutory regulations in a manner which does not give rise to danger.
In the the Management of Health and Safety Regulations case of work of an electrical nature, it is preferable that , the COSHH Regulations , the Provision the conductors be made dead before work commences.