20-09-2016, 02:12 PM
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INTRODUCTION
Having studied wires and cables it is important to know about electrical controlling , safety, outlet and general accessories.
In an electrical circuit fuse is used as a safety device. Here we are going to discuss about their characteristics and uses. Earthing is also used for safety. It prevents to minimize the risk of shock. The purpose functions and types of earthing are also discussed.
OBJECTIVES
explain the purpose of fuse in the circuits
identify the different types of fuses and their uses
Switches-
A manually operated device for closing & opening a circuit is known as switch. One way switch Single Pole Switch-
Flush, wll mounting or switches is the most popular switches in domestic wiring. The flush (piano) switch must be fixed on a PVC gangbox or on wooden box. The gangboxes ate available in 1gang 2,3, 4, & 6 gang according to no. of switches. Standard gang boxes are designed so that the switch is fixed by screw directly or indirectly (push pull type) 0. (fig ) One way switch to has current rating 6amperes. These are used for light & fan point rating of power switches is 16 amperes & are used for freeze, mixer, washing machine, geezer, etc. (fig.-S.P. switch)
Two-way switch-
This type of switch having 3 terminals. Centre terminal, is known as common terminal ©. Above terminal of common terminal is Upper terminal (u) & below of the common terminal is Lower terminal (L). Two way switch has current rating 6 amperes only. These are used for stair case wiring, godown wiring, hospital wiring. (fig.- Two-way switch)
Bellpush-
This type of switch having two terminals with spring loaded push button. When we push it makes the circuit temporarily & attends break position when released. It is used in call bell circuit, current rating is 6 ampere & suitable for 250V only. (fig.- Bellpush)
D.P. Switch (Double Pole Switch)-
This switch is consist of double pole switch, fuse, fuse link & neon indicator. These switches are used as main switches to controlled main or branch circuit in domestic installation. They are available in 10ampere, 16ampere & 32 ampere & suitable for 250V only. (fig.- D.P. switch) single pole), two way switch, Bell push, double pole switch ( D.P. switch)