1. Practical Electrical Wiring

2. Steps :
1- Calculate wattage for lighting of each room
Incandescent : Wattage = 0.2 X Area X Lux
Fluorescent : Wattage = X Area X Lux
Usually in Kitchen and Bathrooms
2- Determine No. of lamps and there wattage in each room
Example: Living room 9.5 m2 with 200 Lux
Required  Prequired= 0.2 X 9.5 X 200 = 380 watt
Installed  Pinstalled = 4 X 100 w lamps = 400 watt

3. Currents of rooms connected to this line
3- Determine the current supplied to each room for lighting
Inc. =1
F. =0.6
4- Choose No. of Light circuits (Usually 2)
Almost equal currents & no overlap
Currents of rooms connected to this line
Diversity factor or Demand factor

4. IN1= ILargest socket on N1 + 0.2 ∑ I other sockets
5- Socket branch circuit calculation :
Normal sockets:
For general devices , 2 A, 5 A or 10 A
Socket Lines : N1 , N2 , N3 , …..
Each line has 5  7 sockets
IN1= ILargest socket on N ∑ I other sockets

5. (b) Power Sockets:
Each special device has its own branch circuit
If this device contains motor
Due to starting current ( In lecture 1.25)

6. 6- Circuit Breakers and Main Feeder
MCB = 10 , 15 ,20 ,25 ,32 ,40 ,63 A
Lecture: Rating of CB = 120% of the Line current
For cross-sections
δ = 5 A/mm2
CSA = 2 ,3 ,4 ,6 ,10, 16 , 25 mm2
Lecture: Light Lines 2.5 mm2
Normal sockets 4 mm2

7. Line
Current CB
CSA
IL1
IL2
IN1
IN2
IP1

8. I Main
IL1
IL2
IL3
IN1
IN2
IP1

9. Chandelier
Inc. Lamp
Normal Socket
F. Lamp
F. Lamps
Power Socket
Lighting switch
1 Gang
Panel Board
Lighting switch
2 Gang

10. Problem(1):
Given:

11. 3x4
3x5
3.5x2
2x2
6.5x5
3x4
2x3
2x3.5
3x5
3x3.5

13. Currents of rooms connected to this line
ROOM
LUX
Area (m2)
Type
Wattage (watt)
Lamps
Installed Wattage(watt)
Current (Amp)
Line1
Line2 1
Entrance Hall 50 6 I 60
1X60
0.27 2
Living
150
32.5
975
2X5X100
1000
4.55 3
Balacony 7 70 4
KTichen
300 12 F
244.8
6X40
240
1.82 5
Salon
200
480
5X100
500
2.27
Bathroom 1
122.4
3X40
120
0.91
Bathroom 2
81.6
2X40 80
0.61 8
Bedroom 1
100 15
3X100
1.36 9
Bedroom 2 10
Bedroom3
10.25
205
1X200
6.91
7.42
MCB
CSA
2.5 mm2
Inc. =1
F. =0.6
Select Lamps:
INC:50 , 60 , 100 , 150 , 200 watt
F: 20 , 40 watt
Calculate Installed Wattage
Diversity factor
4.56
4.9
Currents of rooms connected to this line
Calculate wattage for lighting of each room
Incandescent : Wattage = 0.2 X Area X Lux
Fluorescent : Wattage = X Area X Lux

14. 6

15. 6
Line 1
Line 2

16. Sockets Normal Sockets: Given in Problem :
All 5 A on 3 Lines . Each line carries 5 7 Sockets
In some problems may be (4  6) as in lecture
So we have 15  21 socket
Power Sockets:
Air Conditioner in Living 4 Hp
Washing machine in Kitchen 1500 watt

17. 24 23 21 25 27 28

18. IN1= ILargest socket on N1 + 0.2 ∑ I other sockets
Normal Sockets:
All 5 A on 3 Lines . Each line carries 7 Sockets
IN1=IN2= x ( 6X 5 ) = 11 A
IN1= ILargest socket on N ∑ I other sockets
MCB = 15 A or 16 A (Available)

20. Power Sockets:
In Living
For Starting current
Lecture: 125% not 250% as in book
In Kitchen

21. Current MCB CSA IL1 4.56 A 10 A 2 X 2.5 mm2 IL2 4.9 A IN1 11 A 15 A
IP1
21.2 A
25 A
2 X 6 mm2
IP2
14.2 A
20 A
For cross-sections
δ = 5 A/mm2

22. I Main
IL1
IL2
IN1
IN2
IN3
IP1
IP1
Main MCB = 63 A CSA = 16 mm2