Domestic Installation: Switch Circuits

1. Eng. Islam Al-Jarrah Domestic Installation: Switch Circuits Module-4

2. Objectives • differentiate between the two types of lighting circuits. • state the purpose of a switch in lighting circuits. • differentiate between one-way and two-way switch circuits. • state the function of intermediate circuits. • use Ingenatic trainer software to build simple switch circuits • install, test and operate simple switch circuits. Eng. Islam Al-Jarrah

3. Introduction to Lighting Circuits • What are domestic Lighting Circuits? • They are radial circuits in which the power cable runs from one fitting to the next until the last fitting where it terminates. Eng. Islam Al-Jarrah

4. House lighting circuits (wiring) • Types of wiring in lighting circuits are as follows: • Loop Type Circuit: • the power is fed from the consumer unit to the first light, then to each consecutive light on the circuit and terminates at the last light. • Junction Box Circuit: • the power cable is fed from the consumer unit to each junction box, finally terminating at the last junction box. Eng. Islam Al-Jarrah

5. Loop Type Circuit the power is fed from the consumer unit to the first light, then to each consecutive light on the circuit and terminates at the last light. Eng. Islam Al-Jarrah

6. Junction Box Circuit the power cable is fed from the consumer unit to each junction box, finally terminating at the last junction box. Eng. Islam Al-Jarrah

7. Lighting Circuits Info • The cable used for a lighting circuit could be: • 1mm2 • 1.5mm2 • The types above depends on: • the length of run • possible rating.  • A Consumer Unit uses a fuse for protecting the lighting circuit which could be: • 5 amp fuse • 6 ampMCB (Main Circuit Breaker) . • The maximum load for a lighting circuit is 1200 watts. • If more lights are needed then another lighting circuit should be used Eng. Islam Al-Jarrah

8. Basics of Lighting Circuits By understanding the simplest ‘One-way switch circuit’ and expanding on the concept, even the most complicated installation circuit can be broken down into easy to understand sub-circuits. Eng. Islam Al-Jarrah

9. Basic Circuit • The simplest form of a circuit is a basic circuit as shown, It literally contains: • 2 conductors(wires), enabling to gain a potential difference • a load, which in the case of a lighting circuit, is a lamp. Eng. Islam Al-Jarrah

10. Switches Typically two wires need to be connected to the terminals of the switch: one bringing the live line second one connected to the load • By installing a “switch” in the circuit the flow of current could be controlled. • Switches come in various designs for different purposes. • For indoor assembly, switches are installed in special boxes with wires running in conduits buried in the wall. Eng. Islam Al-Jarrah

11. Switches for Electrical Installation One Gang One Way Intermediate Switch One Gang Two Way Eng. Islam Al-Jarrah

12. One Way Switch Circuit A one-way switch circuit is used when an electrical load has to be switched on and off from one single location. Eng. Islam Al-Jarrah

13. The circuit could be protected by adding a fuse which is a circuit protection device. One Way Switch Circuit the switch must be located between L1 and the lamp, so that after power cuts off there will not be any connection between the live wire and the lamp.

14. Skill -1 Identify and name the type of lighting circuits Eng. Islam Al-Jarrah

15. Switch, Junction Box, Lamp, Live connection (L1), Neutral connection (N) Skill -2 Identify the type of circuit shown in the figure given below, and name the parts marked by choosing them from the list below Eng. Islam Al-Jarrah

16. Skill -3 (Page -9) • The installation diagram of a 1-way switch circuit is shown in the figure below. Study the diagram and understand the symbolic representations. Eng. Islam Al-Jarrah

17. Two-Way Switch Circuit Used when it is necessary to control a load from more than one point. For example : Staircase Eng. Islam Al-Jarrah

18. Intermediate Switch Circuit If we wanted to add further switches, we can install what we call an intermediate switch between the 2 ways switches. Eng. Islam Al-Jarrah

19. Lab Activities: General Instructions • The complete installation (lighting & sockets) is protected by a Single Phase RCD located in the Distribution Board (D.B.), which also contains MCBs for the various circuits. • Install the internal wiring of the D.B. by using 6 mm2. • Execute the Earthing System by relating to the local Earthing System. • Supply is single phase 240V 50 Hz AC wired distribution board (6 mm2). Eng. Islam Al-Jarrah

20. General Instructions .. Continued • Take note of the following: • Measurements are in millimeters. Tolerance ± 3mm. • Measurements are to the centers of cables/ conduits and equipment as indicated. • When the installation is completed, it must be first tested by the teacher. • When connecting to power, your teacher must be present! Eng. Islam Al-Jarrah

21. Lab Activities • Lab Activity -1 • One-way switch circuit (Page -12) • Lab Activity -2 • two-way switch circuit (Page -14) • Lab Activity -3 • two lights operated by an intermediate switch. (Page -16) Eng. Islam Al-Jarrah