Electrical Installation and Practices
Topic: Types of Electrical wirings and their Selection Wiring accessories Motors and starters
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Contents Fundamentals of electricity Electrical word, definition and unit Wiring System Requirement of electrical installation Types of wiring System. TW Batten wiring PVC Casing Capping Wiring Conduit Pipe Wiring. IE Rules of Wiring. 2
Contents Multy Storage wiring. Wiring Installation Diagram and Symbol. Fault of Wiring. Magger. DC Motor and its Speed Control. Motor use in industries. Starter. Winding. Telephone Wiring. Transformer Winding. 3
Fundamental concept of electrical energy • Introduction. • Importance of electricity. • Use of electricity • 1. In industries : Heating, welding, electroplating. • 2. Domestic : Light, fan, heater, washing machine. • 3. Commercial : Cinema, Lift, water pump, lighting, adverting display. 4
Fundamental concept of electrical energy Direct Current. Alternating current. Source of electricity. 1. Battery. 2. Dc generator. 3. Alternator.
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Electrical word, Definition & Unit Electromotive force. (emf) Current Resistance One Ampere One volt Electric power One watt ( W ) One Ohms Electric energy One kilo watt hour Specific resistance 6
Wiring introduction & system Introduction of wiring. Types of wiring as using. 1. Domestic Wiring. 2. Commercial Wiring. 3. Industrial wiring. Wiring System 1. Tree System. 2. Looping System. (a) Switch and two plate ceiling rose or switch and batten holder lopping. (b) Three plate ceiling rose looping. (c) In junction box looping
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Indian electricity rules pertaining to Domestic wiring Electrical Supply line and equipment ’s construction, Installation, protection, operation and safety. Consumer ‘s service line and equipment. Cut out in consumer’s area. Introduction of earth conductor and earth neutral position of switch and cut out. Earth terminal in consumer’s area. Handling of electrical supply line and equipment. Supply of energy and uses. Seal of meter and cut out.
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WIRING Introduction of wiring. Types of wiring according to the Uses. 1. Domestic Wiring. 2. Commercial Wiring. 3. Industrial Wiring.
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Factors Affecting choice of wiring Safety
Duration Appearance Accessibility Maintenance Cost
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Types of Wiring 1. Cleat Wiring 2. Batten Wiring (a) PVC Batten wiring. (b) TRS/CTS Wiring. (c) Lead Sheath Wiring. 3. Casing Capping wiring (a) Wood Casing capping Wiring (b) PVC Casing Capping Wiring.
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Types of Wiring 4. Conduit Wiring (a) Surface conduit wiring Metal Conduit Wiring PVC conduit wiring (b) Cunsild Conduit Wiring Metal Conduit Wiring. PVC Conduit wiring.
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CLEAT WIRING • Introduction The types of wiring to be adopted is dependent on various factors, viz, durability, safety, appearance, cost, consumer’s budget etc. • Cleat wiring This System uses insulated Cables sub protected in porcelain cleats.
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CLEAT WIRING Cleat wiring is recommended only for temporary installations. The cleats are made in pairs having bottom and top halves. The bottom half is grooved to receive the wire and the top half is for cable grip. Initially the bottom and top cleats are fixed on the wall loosely according to the layout. Then the cable is drawn, tensioned and the cleats are tightened by the screw. Cleats are of three types, having one, two or three grooves, so as to receive one, two or three wires. Two types of cleats.
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CLEAT WIRING • Cleat wiring is one of the cheapest wiring considering the initial cost and labor, and is most suitable for temporary wiring. This wiring can be quickly installed, easily inspected and altered. When not required, this wiring could be dismantled without damage to the cables, cleats and accessories
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CLEAT WIRING
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CLEAT WIRING • B.I.S. RECOMMENDATIONS FOR CLEAT WIRING • General This system shall not be employed for wiring on damp walls or ceilings unless precautions are adopted for effectively preventing dampness and thus the deterioration of the insulation of the conductors. • Accessibility Cleat wiring shall be run, as far as practicable, so as to be visible. In positions where they would be liable to mechanical injury and where they are less than 1.5 m above the floor, they shall be adequately protected. 17
CLEAT WIRING • Class of cables Vulcanized rubber insulted cables, PVC and polythene insulted cables, braided or unbraided insulted cables could be used without any further protection. • Cleats All cleats shall consist of two parts, a base piece and a cap. Cleats shall be fixed at distances not more than 60 cm apart and at regular intervals.
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CLEAT WIRING Where cleat wiring is laid along an iron joist, porcelain cleats shall be inserted either with varnished wood fillets or varnished wood clamps securely fixed so as to prevent the conductors from coming in contact with the metal along witch they are passing. • Fixing of cleats In ordinary cases, cleats shall be attached to wooden plugs fixed to the walls
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CLEAT WIRING • Distance apart of wires For pressure up to 250 volts, cleats shall be of such dimensions that in the case of branch loads, conductors shall not be less than 2.5 cm apart, centre to centre, and in the case of sub-mains not less than 4 cm apart, centre to centre. Care shall be taken in selecting the size of cleats particularly for branch distribution wiring where two-way and three-way porcelain cleats are essential and the difference in size shall be reasonable. Care should
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CLEAT WIRING • also be taken ensure that grooves of porcelain cleats are essential and the difference in size shall be reasonable. Care should also be taken to ensure that grooves of porcelain cleats do not compress the insulation nor be too wide for a loose fit. Under no circumstances two wires shall be placed in one groove of the porcelain cleats.
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CLEAT WIRING • Crossing of conductors Where cleated conductors cross each other they shall be separated by an insulating bridging piece, which will rigidly maintain a distance of atleast1.3 cm between the conductors. Where joints are required for connecting bifurcating wires, junction boxes with porcelain connectors inside shall be used.
• Protection near the floor No cleat wiring shall be left unprotected up to 1.5 m above the floor level. When brought through the floor it shall be enclosed in a conduit. (IS 732-1963) 22
BATTEN WIRING • Batten Wiring Tough rubber-Sheathed (T.R.S.) or PVC- Sheathed cables are suitable to run on teak wood battens. • Varnishing of teak wood batten • Method of securing the battens • Suitability of tough rubber-sheathed cable • Suitability of PVC sheathed cable • Painting • Bending in wiring • Passing through the walls • Buried cable
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BATTEN WIRING • Link Clips Link clips are used for family clipping the cables in position. Link clips are of two types. • Link clip which has separate linking eye. • Joint link clip which has combined linking eye. Link clip are available in the following size.
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BATTEN WIRING 25mm, 32mm, 40mm, 50mm, 63mm, 80mm, out of which up to 40mm clips have one hole, while above that they have two holes for fixing. Fig2 shows the joint link clips. These are available in the sizes 16mm, 25mm, 32mm, 40mm, 50mm, 63mm, 80mm with a thickness of 0.32mm and have one hole up to 40mm while above that they have two hole for fixing. Link clips are made of tin or brass- coated tin or aluminium. 25
BATTEN WIRING
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CASING CAPPING WIRING • Introduction This system of wiring is suitable for low voltage installation, in this wiring, cables like vulcanized rubber, insulated cables or plastic insulated cables are use and carried within the wood casing enclosures. The wood casing wiring system shall not be use in damp places and in ill-ventilated places, unless suitable precautions are taken.
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CASING CAPPING WIRING • Material and pattern of casing All casing shall be of first class, seasoned teak wood or any other approved hardwood free from knots, shakes, saps or other defects, with all the sides planed to a smooth finish, and all sides well varnished, both inside and out side with pure shellac varnish. The casing shall have a grooved body with a beaded or plain- moulded cover as desired.
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CASING CAPPING WIRING • Dimensions of casing. The size of casing and capping to be used for various sizes of 250 volts grade insulated cables in a groove shall be in accordance with those specified in table 1. • Bunching of circuits. • Attachment of casing to wall and ceiling. • Attachment of capping. • Passing over the floors. • Joints in casing and capping. 29
CASING CAPPING WIRING •
Types of Joint 1. Straight joint. 2. Tee joint. 3. Right- angled joint. 4. Corner joint. 5. Tee-bridge joint. 6. Cross- bridge joint.
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CASING CAPPING WIRING 1. Straight joint.
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CASING CAPPING WIRING 1. Tee joint.
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CASING CAPPING WIRING 1. Corner joint.
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CASING CAPPING WIRING • Half-lap T joint
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CASING CAPPING WIRING • Cross- Joint
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CONDUIT WIRING •
Introduction In general, a conduit is defined as a tube or channel. Tubular conduit is the most commonly used material in electrical installations. When cables are drawn through the conduit and terminated at the outlet or switch points, the system of wiring is called conduit wiring.
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CONDUIT WIRING • Types of conduits. There are four types of conduits used for wiring. 1.Rigid steel conduit 2.Rigid non-metallic conduit 3.Flexible steel conduit 4.Flexible non metallic conduit.
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CONDUIT WIRING •
PVC Fittings and accessories couplers 1. Couplers 2. Elbow 3. Bends 4. Tee 5. Circular boxes 6. Rectangular boxes.
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CONDUIT WIRING • Couplers
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CONDUIT WIRING • Elbow
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CONDUIT WIRING • Bends
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CONDUIT WIRING • Tees
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CONDUIT WIRING • Circular boxes
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CONDUIT WIRING • Rectangular boxes
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CONDUIT WIRING • Junction Boxes
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DC Motor Introduction of DC motor. Principal and operation of DC motor. Motor Characteristics. Types of Dc motor. 1. DC Shunt Motor 2. DC Series Motor 3. DC Compound Motor. 4. DC Different ional Compound Motor Starting of DC Motor Speed Control of DC Motor. 46
A C Motor Different types of variable speed AC Motors and their control. Different types of motors used in industries. •Squirrel cage induction motor
•Slip ring induction motor •Single phase induction motor
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A C Motor Classification and cooling methods Motor size, speed and their method of wiring Motor connection and earthling Application of 3-point, 4 point star delta starters.
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Types of Winding Introduction DC machine winding 1. Lap winding 2. Wav winding - Pole Pitch, Back pitch, Front pitch, winding pitch, coil pitch. AC machine winding 1. Single phase winding 2. Three phase winding 1. Single layer winding 49 2. Double layer winding
Transformer winding
• Introduction of transformer winding • Prepare data of transformer
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Starters A C Motor • • •
Introduction Requirement of Starter Different types of Starter – Direct on line Starter – Auto Transformer Starter – Star-Delta Starter – Rotor resistance Starter • Working principal of all different types of starter. 51
Single phase A C Motor • •
Introduction Types of Single phase induction motor. – Shaded pole motor – Capacitor Start Induction run motor – Capacitor start capacitor run motor.
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MEGGER • • • • • • • •
Introduction Varies uses of megger 1) To measure insulation resistance of wire. 2) Testing of faults. 3) Testing of continuities of circuits. 4) To measure earth resistance . Structure of megger Megger use as a earth tester 53
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