EEE 2100 Electrical shop practice RK HASAN RJ

syllabus Electrician’s tools, splices, soldering, code practices. Electrical and electronic symbols. Safety rules, electricity rules and electricity codes. Electrical wiring system design, drawing and estimation for residential and commercial house wiring and Industrial installation wiring. Use of meggers, Insulation test, Grounding, Earth resistance measurement using earth resistance tester. Battery charging. 2

Electrician’s tools 3

List of tools Lineman’s Pliers Side Cutters Cable Cutters Crimping Pliers Needle Nose Pliers Wire Strippers Electrician Scissors Tape Measure Electrician Hammer Crescent Wrench Hack Saw Tri-Square Tin Snips Wrench Set Nut Drivers Variable Screwdriver Socket Set Skinning Knife Multimeter Voltage tester 4

symbols 5

Symbols(contd.) 6

ELECTRICAL HAZARDS  Shock  Burns  Arc flash/blast  Explosions  Fires Shock (AC) More than 3 mA- Painful shock- cause indirect accident More than 10 mA- Muscle contraction - “No Let Go” danger More than 30 mA- Lung paralysis, usually temporary More than 50 mA- Ventricular fibrillation, usually fatal 100 mA to 4 A- Certain ventricular fibrillation, fatal Over 4 A- Heart paralysis, severe burns 7

ISO symbols for electrical hazards HIGH VOLTAGE HAZARD WARNING BATTERY CHARGING ELECTRICAL SHOCK HAZARD ARC FLASH HAZARD 8

Safety precautions for personnel's Hard hat Goggles Gloves Electricity jacket Rubber boots Ear muffs for noisy area Trimmed or confined hair First-aid box etc. 9

Standard wire gauge (S. W. G.) 10

Electrical wiring joints Britannia joint Straight joint Tee joint Western union joint Married joint Rat tail joint Fixture joint 11

12 Britannia joint

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Megger Earth resistance testing  What do you mean by ‘earth resistance’?  What should be its value? 15

Switch board Switch board is a board made up of either wood or plastic (PVC) and is meant for mounting switches and sockets The procedure of cutting of holes of appropriate size and fixing of switches and sockets on switchboard is known as mounting of switches Construct ONE 16

Mcb & fuse Actuator lever 2. Actuator mechanism 3. Contacts. 4. Terminals 5. Bimetallic strip. 6. Calibration screw 7. Solenoid 8. Arc divider/extinguisher (Arc Chute) What are the differences between fuses and circuit- breakers?

Electrical wiring Total power dissipation = W Permissible line voltage drop = 2lW/λVA Where V= low voltage value A= area of cross-section of wire λ = 56 for Cu 18

Electrical wiring and estimation of conductor size:  Residential/Domestic  Commercial  Industrial 19 Phase wire: red, blue, yellow Neutral wire: black

20 Wish you an electrifying career