System of Wiring

State electricity board provide electric supply up to a point outside the consumer premises. From this point consumer take the connection to his main board. Insulated electrical wires will be taken out to various places in the premises to supply power to different type of loads like lights, fans, refrigerators, room coolers, heaters, etc.

Various type of Wiring:-

1.Cleat Wiring.2.Wood casting Wiring.3.Batten Wiring.4.Conduit Wiring.

• Cleat Wiring:-cleat are made by porcelain and fixed on wall or ceiling at interval of 0.6 m. The cable is taken through the holes of each cleat. such a wiring is cheap & use in temporary installation.

• Wood casting Wiring:-In this Wiring the cable is run through a Wood casting having grooves. The cable are placed in side the grooves of the casting. A capping also made of wood with grooves , is used to cover the cables . The casting and capping are made from well-seasoned teak wood. Wood casting Wiring system are use in dry place like Rajasthan.

• Batten Wiring:-In Batten Wiring insulated wires are run on wooden battens.PVC wires are run on well-seasoned straight teak wood battens. Batten Wiring is cheap & takes comparatively less time to install.

• Conduit Wiring:-Conduit Wiring consists of PVC wires taken through either steel conduit pipes or through PVC conduit pipes. Conduit are over the surface of wall and ceiling . when Conduit are run over the surface of wall ,the wiring is called as surface Conduit Wiring . when Conduit are run inside wall, the wiring is called as concealed Conduit Wiring. Conduit Wiring is water proof & replacement of defective wire is very easy.

Safety precaution in using Electricity:-

1.Every circuit should be given supply through a switch-fire arrangement

2.The phase provided should be of proper rating.3.No connection should be taken directly using

naked wire.4.All metallic parts of electrical equipment

should be earthed.

Circuit protective device and safety precaution:-

• Circuit should be protected against any abnormal condition like overload or short circuit which may be due to any fault condition or excess load connected to the circuit. protective device like fuses, circuit breakers are used , which help protect the circuit from burning under abnormal condition.

Fuses

• A fuse is a short piece of metal , inserted in the circuit ,which melts when excessive current flows through it and thus break the circuit.

Desirable characteristics of fuse element:-

Type of fuses

1.Low voltage fuse:-a. semi-closed rewirable type.b.High rupturing capacity(H.R.C) cartridge

type.

2.High voltage fuse.

Circuit Breakers

A circuit breaker will break the circuit automatically under any fault conditions. Circuit breaker can be operated by remote control with the help of relay .Relay detect the fault and initiate tripping of the circuit breaker. under fault conditions the electrical quantities like current, voltage and frequency become abnormal and is sensed by the relay.

Classification of Circuit Breaker:-

1.Oil Circuit Breaker.2.Air-blast Circuit Breaker3.Sulphur Hexafluoride (SF6) Circuit Breaker.4.Vacuum Circuit Breaker.

Efficient use of Electricity:-

1. Lighting, heating, cooling and other domestic electrical appliances used in home.

2. Street lighting, flood lighting of sporting arena, office building lighting, powering PCs etc.

3. Irrigating vast agricultural lands using pumps and operating cold storages for various agricultural products.

4. Running motors, furnaces of various kinds, in industries.

5. Running locomotives (electric trains) of railways.

Purpose of Earthing

• To save human life from danger of electrical shock or death by blowing a fuse i.e. To provide an alternative path for the fault current to flow so that it will not endanger the user

• To protect buildings, machinery & appliances under fault conditions   ie. To ensure that all exposed conductive parts do not reach a dangerous potential.

• To provide safe path to dissipate lightning and short circuit currents. • To provide stable platform for operation of sensitive  electronic

equipments   i.e. To 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 . 

• To provide protection against static electricity from  friction