Distribution Board Earth Leakage Circuit Breaker (ELCB) Main Switch (MCB) 51
Distribution Board E N L Connection to the light load, the fan, socket, remote control cooker, electric bells, air conditioning and control devices. From KWh meter Grounding 52
6A Accessories Connection Lamp circuit controlled by a one-way switch C 1W From KWh meter 53
6A Accessories Connection Lamp circuit controlled by two switches two way C C 1W 1W 2W 2W From KWh meter 54
Accessories Connection Dari meter KWj 6A C 1W 2W 1WC 2W Lamp circuit controlled by two switches two way and one intermediate switch From KWh meter 55
Accessories Connection Dari meter KWj 13A output socket connection radial circuit 16A From KWh meter 56
Accessories Connection Dari meter KWj 13A output socket connection circuit ring 16A From KWh meter 57
Accessories Connection 16A Sockets output 13A From KWh meter 13A connection output socket outlet 58
Accessories Connection Circuit controlled ceiling fans by a one-way switch from KWh meter C 1W 6A 59
2.2 ELECTRICAL INSTALLATION TOOLS • Combination pliers • Screwdrivers • Hammers • Gimlets • Cable cutters • Test pens 60
Combination Pliers • Linesman’s Pliers Are specifically designed for cutting, bending, and twisting wire. While commonly used by construction workers and electricians, they are very useful tools for the service tech who deals with wiring. • The center parts of the jaws are designed to grasp round objects such as pipe or tubing without slipping. 61
• Phillipsscrew drive was purposely designed to cam out when the screw stalled and to prevent the fastener damaging the work or the head. • Slot screw drive has a single slot in the fastener head and is driven by a "common blade" or flat-bladed screwdriver. • It was the first type of screw drive to be developed, and for centuries it was the simplest and cheapest to make. Screwdriver 62
Hammer • A hammer is a tool that delivers a blow (a sudden impact) to an object. • The most common uses for hammers are to drive nails, fit parts,forge metal, and break apart objects. • Hammers vary in shape, size, and structure, depending on their purposes. • The usual features are a head (most often made of steel) and a handle (also called a helve orhaft). 63
Gimlets • A gimlet is a hand tool for drilling small holes, mainly in wood, without splitting. • It was defined in Joseph Gwilt's Architecture (1859) as "a piece of steel of a semi-cylindrical form, hollow on one side, having a cross handle at one end and a worm or screw at the other 64
Test Pen • The test pen is an electric lamp connected with one or two insulated wire leads. Often, it takes the form of a screwdriver with the lamp connected between the tip of the screwdriver and a single lead that projects out the back of the screwdriver. • By connecting the flying lead to an earth (ground) reference and touching the screwdriver tip to various points in the circuit, the presence or absence of voltage at each point can be determined, allowing simple faults to be detected and traced to their root cause. 65
Drill • A drill is a tool fitted with a cutting tool attachment or driving tool attachment, usually a drill bit or driver bit, used for boring holes in various materials or fastening various materials together with the use of fasteners. • The attachment is gripped by a chuck at one end of the drill and rotated while pressed against the target material. 66
TOPIC 3 – WIRING SYSTEM Upon completion of this course, participants should be able to: 1.Apply the concept and principle of electrical safety and regulation in performing electrical wiring according to NIOSH and MS IEC 60364 standard. 2.Construct single-phase domestic wiring according to MS IEC 60364. 3.Demonstrate an understanding and commit to professional ethics and responsibilities of engineering norms and sustainable energy in electrical wiring during performance single phase domestic task. COURSE LEARNING OUTCOME 67
Domestic Wiring • Home typically has several kinds of home wiring for lighting and power distribution, permanently installed and portable appliances, telephone, heating or ventilation system control and computer networks. • Regulations for wiring installation vary widely around the world, with national, regional, and municipal rules sometimes in effect. • Some places allow the homeowner to install some or all of the wiring in a home; other jurisdictions require that licensed electricians only install wiring. 68
Industrial Wiring • Needless to say, industrial wiring is essentially a much more complex form of residential wiring. • Industrial wiring is based on 3-phase electrical power. • With 3-phase electric, the wires are smaller and the motor is smaller than a typical single-phase motor. • These factors allow greater efficiency and longer lasting motors and wires. 69
Types of Wiring • Cleat wiring • CTS wiring or TRS wiring or batten wiring • Metal sheathed wiring or lead sheathed wiring • Casing and capping • Conduit wiring 70
Type of Wiring 71
Type of Cable and Insulators Cable is material or intermediate device connection of electrical energy to electrical equipment. A cable was considered perfect when it has three parts, or at least two of the following parts: • Conductors. • Insulation. • Protection mechanics. If the minimum requirements are not met, it can not be called as a cable or wire but called conductors only. 72
Part of Cable 1. Conductor 2. Insulator 3. Protection mechanics 73
Part of Cable 1. Conductor Cable - Usually made of Copper and Aluminium 2. Cable Insulation - Cable insulation coating and has a high resistance to prevent flow out. 3. Mechanical Protection. - The cover is made to protect the cable from injury due to mechanical hazards like exposed sharps, struck and crushed. 74
Insulator • Various material and insulation layers are used for conductor protection. • Cable selection in accordance to insulation layers must be done correctly • for the type of the wiring installation as shown in the table below: 75
MS IEC 60364 and Electricity Regulation 1994 • The Guidelines For Electrical Wiring In Residential Buildings has been prepared as a wiring guide for all Wiremen and Electrical Contractors for undertaking electrical wiring in residential buildings to conform to the Electricity Regulations 1994. • The Guidelines are prepared in a concise and compact manner to facilitate the electrical wiring of residential buildings to be done adequately and to ensure its safety of use while meeting basic wiring requirements. • The Guidelines will also be useful for owners of residential buildings or wiring installations to recognize the requirements of safe and adequate electrical wiring. 76
Correction Factor • If a number of cables is installed together and each is carrying current, they will all warm up. • Those which are on the outside of the group will be able to transmit heat outwards, but will be restricted in losing heat inwards towards other warm cables. • Cables 'buried' in others near the centre of the group may find it impossible to shed heat at all, and will rise further in temperature. a) widely spaced cables dissipate heat easily b) A closely packed cable cannot easily dissipate heat and so its temperature rises 77
Correction Factor Ca - symbol for the correction factor for ambient temperature Cg - symbol for correction factor for cable grouping 78
Ambient Temperature • The standard or reference temperature for the installation of cables is 30oC. • If cables are installed in conditions where the ambient temperature is in excess of this then a correction factor must be able when calculating the required cable cross section. • A table of correction factors for ambient temperature may be viewed in BS7671. The symbol for the Correction factor for ambient temperature is Ca. 79
Select Cable Sizes • The cable size is selected based on the size of the device protecting it, having considered the above Where It ≥ In/(Ca x Ci x Cg x Cc) • In the absence of any stated or recognised external influences for an installation all correction factors assume a value of 1 (ie: does not change the final figure). 80
Select Cable Sizes • If you are familiar with Cable Calculations the following should be recognisable to you: • So you may wish to attempt these question: 81
Select Cable Sizes 82
Select Cable Sizes 83
Select Cable Sizes 84
MS IEC 60364 and Electricity Regulations 1994 rules and regulations Selection of cable size based on MS IEC 60364 and Electricity Regulations 1994 rules and regulations: a. The type of cable, color code and its use b. Proper cable selection such as • Current carrying capacity • Voltage drop calculation • Diversity factors and • Correction factors c. The type of cable and termination 85
TOPIC 4 – WIRING PROTECTION Upon completion of this course, participants should be able to: 1.Apply the concept and principle of electrical safety and regulation in performing electrical wiring according to NIOSH and MS IEC 60364 standard. 2.Construct single-phase domestic wiring according to MS IEC 60364. 3.Demonstrate an understanding and commit to professional ethics and responsibilities of engineering norms and sustainable energy in electrical wiring during performance single phase domestic task. COURSE LEARNING OUTCOME 86
4.0 WIRING PROTECTION Protective Devices • Over Current Protection • Fuse and Circuit Breaker • Earthing 87
4.1 Over Current Protection 1) Short circuit Two or more live conductor touching each other 2) Overload Adding loads greater than that of the rated value 3) Earth fault A phase conductor touching the protective conductor by means of direct or indirect contact 88
4.1 Over Current Protection There are two types of protective devices : 1. cartridge fuse 2. miniature circuit breaker (MCB) 89
4.2 Fuse and Circuit Breaker • Fuse is a type of sacrificial Over current protection device. • Its essential component is a metal wire or strip that melts when too much current flows, which interrupts the circuit in which it is connected. • Short circuit, overload or device failure is often the reason for excessive current. 90
Fuse • A fuse interrupts excessive current (blows) so that further damage by overheating or fire is prevented. • Wiring regulations often define a maximum fuse current rating for particular circuits. • Overcurrent protection devices are essential in electrical systems to limit threats to human life and property damage. Fuses are selected to allow passage of normal current and of excessive current only for short periods. 91
Fuse The advantages of a cartridge fuse are : 1) Fuse element does not deteriorate after many years 2) Small in size 3) Easy and quick to replace 4) Needs no maintenance The disadvantages of a cartridge fuse are : 1) Does not suit high fault current 2) Spare cartridge fuse must be available 3) Can be shorted out by the use of metal foil 92
Circuit Breaker • A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload short circuit. • Its basic function is to detect a fault condition and, by interrupting continuity, to immediately discontinue electrical flow. 93
Circuit Breaker • Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. • Circuit breakers are made in varying sizes. • From small devices that protectant individual household appliance up to large switchgear designed to protect high voltage circuits feeding an entire city. 94
Circuit Breaker The advantages of a miniature circuit breaker (MCB) are : 1) Shorter tripping time 2) Can be reused 3) Easy to reset 4) Has a switch that can isolate the equipment The disadvantages of a miniature circuit breaker (MCB) are : 1) The most expensive protection device for home use 2) Slow tripping time due to aging 3) Surrounding temperature may affect the MCB 95
4.3 Earthing Earthing • The earth is made up of materials that is electrically conductive. A fault current will flow to 'earth' through the live conductor, provided it is earthed . • This is to prevent a potentially live conductor from rising above the safe level . All exposed metal parts of an electrical installation or electrical appliance must be earthed . 96
Earthing The main objectives of the earthing are to : • Provide an alternative path for the fault current to flow so that it will not endanger the user. • Ensure that all exposed conductive parts do not reach a dangerous potential. • Maintain the voltage at any part of an electrical system at a known value so as to prevent over current or excessive voltage on the appliances or equipment . 97
Earthing The qualities of a good earthing system are : • Must be of low electrical resistance • Must be of good corrosion resistance • Must be able to dissipate high fault current repeatedly 98
Earthing 99
TOPIC 5 – INSPECTION AND TESTING Upon completion of this course, participants should be able to: 1.Apply the concept and principle of electrical safety and regulation in performing electrical wiring according to NIOSH and MS IEC 60364 standard. 2.Construct single-phase domestic wiring according to MS IEC 60364. 3.Demonstrate an understanding and commit to professional ethics and responsibilities of engineering norms and sustainable energy in electrical wiring during performance single phase domestic task. COURSE LEARNING OUTCOME 100