Practical Electrical Wiring

Steps : 1- Calculate wattage for lighting of each room Incandescent : Wattage = 0.2 X Area X Lux Fluorescent : Wattage = 0.068 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

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

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 N1 + 0.2 ∑ I other sockets

(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- 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

Line Current CB CSA IL1 IL2 IN1 IN2 IP1

I Main IL1 IL2 IL3 IN1 IN2 IP1

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

Problem(1): Given:

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

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 = 0.068 X Area X Lux

6

6 Line 1 Line 2

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

24 23 21 25 27 28

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= 5 + 0.2 x ( 6X 5 ) = 11 A IN1= ILargest socket on N1 + 0.2 ∑ I other sockets MCB = 15 A or 16 A (Available)

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

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

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