Page 118 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

Wiring accessories, IE Rules

Objectives: At the end of this lesson you shall be able to:
• classify, specify, identify and state the uses of the accessories employed in domestic wiring
• state the IE rules related to safety and electric supply.

Electrical accessories: An electrical domestic accessory is a basic part used in wiring either for protection and
adjustment or for the control of the electrical circuits or for a combination of these functions.
Rating of accessories: The standard current ratings of the accessories are 6, 16 and 32 amps. The voltage
rating is 240V AC as per B.I.S. 1293-1988.
Mounting of accessories: The accessories are designed to mount either on the surface or concealed (flush
type).
Surface mounting type: Accessories are provided with a seating so that when mounted they project wholly
above the surface on which they are mounted.
Flush-mounting type: These accessories are designed to mount behind or incorporated with a switch plate, the
back of the plate being flush with the surface of the wall or switch box.
The electrical accessories used in wiring installation, are classified according to their uses.
– Controlling accessories
– Holding accessories
– Safety accessories
– Outlet accessories
– General accessories
Types of switches according to their function and place of use
1 Single pole, one-way switch
2 Single pole, two-way switch
3 Intermediate switch
4 Bell-push or push-button switch
5 Pull or ceiling switch
6 Double pole switch (DP switches)
7 Iron clad double pole, (ICDP) switch.
8 Iron clad triple - pole (ICTP) switch.
Of the above 1,2,3,4 and 6 may be either surface mounting type or flush-mounting type.
Single pole, one-way switch: This is a two terminal device, capable of making and breaking a single circuit only.
It is used for controlling light or fan or 6 amps socket. (Fig 1)
Two-way switch: This is a three terminal device capable of making or breaking two connections from a single
position (Fig 2). These switches are used in staircase lighting where one lamp is controlled from two different
places.
Intermediate switch: This is a four-terminal device capable of making or breaking two connections from two
positions (Fig 3). This switch is used along with 2 way switches to control a lamp from three or more positions.

Fig 1 Fig 2 Fig 3

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CITS : Power - Electrician & Wireman - Lesson 20-25 CITS : Power - Electrician & Wireman - Lesson 20-25