House wiring Different systems of wiringThe various systems of domestic and industrial wiring are: 1.cleat wiring 2.casing capping 3.c.t.s wiring 4.metal sheeted wiring 5.conduit wiringBefore deciding the type of wiring opt be used at a particular site the following points should beconsider:a.durability: the wire selected should b able to with stand for a long period against weather changes.b.Safety: safety is the foremost point to be kept in veiw while making decision of the system of wiring. Itmay not prove to be risky. At places, which are not free from fire danger, coundict wiring is preferredc.cost: the cost of wiring installation is one of the main points to b considered. The system closen shouldbe economical and with in the needs of indivisual.d.apperence: wiring apperence has itz own effect. Architectural beauty should b kept in view.1)cleat wiring: in this system V.I.R wire used bin procelin cleats. The cleats are of three types,haivbinone,two ro three grooves so as to recive one,two or three wires.they are made in two halves. One Isgrooved to recive the wire while the other is put over it and the whole is fixed on the wall. The systemof installation is cheap n most suitable for temporary wiring. It can b easily installed and also removedquickly when not require.2) wood casing capping: the system of wiring recommanded to be made of well seasoned take wood orany other suitable hard wood. At the top it is covered by a strip known as capping. The width of thecappin to show the position of the wires so that screws may not be driven through wrong position.Wood gutties are fixed on the wall seperated by a distance not more than one meter . round porcelindisc insulators are used between the wood gutties and causing. The fixing is done with counter sunkscores into the gutties. The capping is screwd over 15cm, for all sized upto 6 cm. width casings.3)c.t.s wiring: c.t.s cable tyre sheathed wires are availablein single,twin or three cores with acircular oroval shape.the cable is free from the effects of moisture,acids,alkalies and climatic variations.it can beexposed to sun.the cable can beburied under/sasonary work but is usually laid over wood battens.thesystem is even suitable for places where chemical fumes are present.4)metal sheathed wiring: the wire consists of rubber-insulated conductor over which a sheath of lead-aluminium alloy is provided externally.this covering provides protection to the cable frommechanicalinjury.in resential buildings they are run over wooden battens.the sheat should be earthed otherwiseelectrolytic action may take placedue to lealage of current and therby deteriorate thecovering.moreover,earthing prevents the metal covering from becoming alive.these cabels are not
suitable for places where chemical corrision may arise.ther effect on the open ends of cabels aregiven;these cabels are more costly than c.t.s ones.The following points should be notedwhen installing metal-sheathed wiring. 1. Metal clips and saddles used to support the cable should be placed 40cm apar. 2. The supports used should not be of such a material as to cause chemical action with the sheaths. 3. The leas sheath be properly earthed. 4. The cable should be run over a damp place. 5. The cable should be run incondults when crossing the floor or wall. 6. Sharp bends should be avoided.5)conduit wiring: workshops and public buildings, this is the most desireable system of wiring it providesmechanical protection and safety against fire. They can be supported over the wall by saddles n pipehooks.Care and maintenainces of the tools: 1. Pilers: 1) do nut cut steel wires and other hard substances 2. Screw driver: a)the edge should not be too sharp. b)this must sit in the slot of the screw head. c)do not use it as a hammer of a chisel. 3.power: a) keep it well sharpened b)do not use it on metals 4.gimlet: a) it should b kept straight while making holes other wise the screwed portion may damage 5.frimer chisel: a)always strike chisel with mallet
b)grind it on the water stone and sharpen it on the oil stone 6.cold chisel: a) the edge must b property maintained b) there should be no trace of oil substance7.tenon saw or hand x saw: a)keep the teeth sharp with triaqngular file b) protect frm rust c) when not bin use apply Greece8.drilling machine: a)keep the machine always clean and fabricate the parts specifically the gears b)drill bit should be properly fixed in the jaws of the machine c)keep it perpendicular to the place of the job while making holes9.soldering iron: a) before soldring an object first time its bit b)clean the rust or dirt with a sand paer before applyin the soldring iron c)soldrting should not be cover heated10. vice: a)vice should not b used as anvil b)it should not be tightened excessively c)clean regularly after use11.wiring tools:1. combination plier2.side cutting plier3.long nose piler4.screwdriver
15.junction box or cut out 5 amps16.electric bell 230 volts and bell push switch17.bed room transformer 230 volts, 13.5.8 volts18.s.w.g used for expressing the size of wires19.kt-kat 15amps20.c.t.s wire 1/1621.Flexible wire,plastic or silk core22.vtr wire 1/1823.wooden screws 60mm,50mm,no.8 for rectangular24.wooden screws 30mm no.8 for proclein clets 2ways and 3 ways25.wooden screws 12mm no.4 for batton holder26.wooden screws 12mm no.4 for batton holder27.2 pin socket,wall bracket, transformer and wood capping28.Proclein alets 2way and 3 way29.wood batton or reper and bend 15mm, 20mm,12mm etc30.wood casing and capping31.link clips 45mm,35mm and 30mm etc32.nails,12mm no.17 for links clips.33.bare copper wires no.14 s.w.g1.EARTHING: in an electric circuit,power passes from positive to the negative terminal. The earth is thebiggest negative terminal. The tendency for current is to pass to the earth if a suitablecontact/conductor is available. In an electric circuit , if there is any gap due to improper connection,current will not flow in the circuit.but of such a circuit having positive potential is touched by a humanbeing, current will pass through the body into the earth making him a part of the circuit.Human body gets electric shock proportional to voltage. Higher the voltage, higher the damage. Inmany countries like us, Canada etc the domestic voltage is only 110 v against the 220 v being used inindia. So the danger of shock is prevented in those countries where as we have the problem ,due to 20vsupply voltage.
Earthing is a safety device to run an electric conductor in parallel to the circuit connecting body of theequipment and a third point to the earth. By this in case of any open circuit accidentally, the currentwill travel through the earth is illegally necessary for all mechines in factoriesDemonstration: earthing system/3-pin plug/ earth connection. 3. Fuse: fuse is a device to protect electrical equipment against overloading of its components due to short circuits etc. every electrical equipment is designed to with stand certain current rating . if the current supplied is higher , it will damage the equipment. To prevent such damage a thin wire of low melting point alloy of optimum current carrying capacity is near the main switch provided in the circuit exceeds the limit, the fuse wire gets melted breaking the circuit.this saves the electric equipment from getting spoiled by continues exposure to such high current. PRECAUTION: do not use thick wire for fuse as it allows excess current into the circuit and causes heavy damage permently to equipment DEMONSTRATION: types of fuse wire/fuse-holder/cartridge/fuse/replacing a fuse.