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= The load is running at iniatial power factor= Required to be corrected power factor

= kilovolt amperes reactant= Total connected load= After diversity maximum demand

= TCL x [tan (phi)1 - tan (phi)c]

= 50.00== 0= 0.80

(phi)1

(phi)c kVAr 2

kiloWattkVA

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Short Cicuirt Current Calculation

Formula:

k x S t

Where:

I = Short circuit current (Amps)

S = Copper area of conductor (mm) 90.0

t = Duration of short circuit current (seconds) 1

up to 5 seconds maximum

k = Constant to allow for an initial temperature

of 90 C & final conductor temperature of 250 C

= 143

I = 12,870.00 Amps

Notes:

1

2 It shound be ensured that the accessories associated with the cables are also

capable of operation at these values of fault current and temperature.

The formula given is based on the cables being fullly loaded at the start of a short

circuit (conductor temperature 90 C) and a final conductor temperature of 250 C.

=I

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Data:

total connected load: = 50.00 KiloWatt

Operating Voltage: = 440 Volts

Phase: = 3

Frequency: = 60 Hz

Total Distance: = 295 Feet cm

Power Factor: = 90% meter

I full load = (KW x 1,000)/^0.5xVxPF)

I full load = 72.90 Amps

Proposed Wire Size: = 90.0 mm

Where:

K = Resistance of conductor per foot

12 for circuits loaded more than 50% of conductor =

current carrying capacity

11 for circuit loaded not more than 50% of conductor =current carrying capacity

18 for aluminum conductors =

L = length of conductor,(feet)

I = Full Load current

d = cross-section of conductor in Circular - Mill =

0.0005067 mm per Cir-Mil

d = 177619.8934 CM

Vdrop = 2.31889387 volts

% Vdrop = 0.47%

Notes:1. Voltage Drop shall not exceed 3% of operating voltage

2. Increase of conductor as necessary to limit voltage drop to < 3%

90.00

Voltage Drop Calculation:

0.0005067

12

11

18

V drop = ((2xK) x L x Ifull load)/ d x 87%

8,997.70

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Table 4.9 Volt drops for mineral

p.v.c sheath p.v.c sheath p.v.c sheath bare sheath bare sheath Cross-sec Single-phase Single-phase

2xsingle/twin 3 core 3 x single 2xsingle/twin 2xsingle/twin area p.v.c sheath bare

(A) (A) (A) (A) (A) (mm) (mV/A/m) (mV/A/m)

1.0 (500V) 18.5 15.0 17.0 22.0 21.0 1.0 42.0 47.0

1.5 (500V) 23.0 19.0 21.0 28.0 27.0 1.5 28.0 31.0

2.5 (500V) 31.0 26.0 29.0 38.0 36.0 2.5 17.0 19.0

4.0 (500V) 40.0 35.0 38.0 51.0 47.0 4.0 10.0 12.0

1.0 (750V) 19.5 16.0 18.0 24.0 24.0 6.0 7.0 7.8

1.5 (750V) 25.0 21.0 23.0 31.0 30.0 10.0 4.2 4.7

2.5 (750V) 34.0 28.0 31.0 42.0 41.0 16.0 2.6 3.0

4.0 (750V) 45.0 37.0 41.0 55.0 53.0

6.0 (750V) 57.0 48.0 52.0 70.0 67.0 Formula:

10.0 (750V) 77.0 65.0 70.0 96.0 91.0

16.0 (750V) 102.0 86.0 92.0 127.0 119.0

Table 4.8 Current rating of mineral insulated cables clipped

directVolt drops for mineral insulated cables (from [Tables 4G1B &4G2B] o

(from [Tables 4G1B & 4G2A] of BS 7671:2008

Cross-sec

(mV/A/m(f

area

(mm)

VDrop =

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insulated cables

Three-phase Three-phase

p.v.c sheath bare

(mV/A/m) (mV/A/m)

36.0 40.0

24.0 27.0

14.0 16.0

9.1 10.0

6.0 6.8

3.6 4.1

2.3 2.6

BS 7671:2008)

or selected cable))(IF)(L)

1000

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Under Armour Armour wire Dia OverallCURRENT

RATING

mm mm mm mm kg / km Ohm / km Ohm / km Amp

1.5 * 9.1 0.9 13.5 380 8.8 12.1 25

2.5 * 10.6 0.9 14.5 445 7.7 7.41 33

4 * 11.4 0.9 17 550 6.8 4.61 44

6 * 13 1.25 18.5 770 4.3 3.08 56

10 * 15 1.25 20.5 1020 3.7 1.83 78

16 * 18 1.25 23.5 1320 3.1 1.15 99

25 20 1.6 26.1 1840 2.3 0.727 131

35 22.8 1.6 28.6 2310 2 0.524 162

50 25.5 1.6 32 2970 1.8 0.387 197

70 29.5 2 37.7 4240 1.2 0.268 251

95 33.5 2 41.7 5400 1.1 0.193 304

120 37.5 2.5 47.1 7000 0.76 0.153 353

150 41.5 2.5 51.4 8350 0.68 0.124 406

185 46 2.5 56.6 10130 0.61 0.0991 463

240 52.5 2.5 63 12840 0.54 0.0754 546

300 57.5 2.5 68.8 15530 0.49 0.0601 628

400 65 3.15 78.1 19950 0.35 0.047 728

mm mm mm kg/km ohm/km amp mV/A/m amp

1.5 0.7 3.4 22 12.1 22 31 19

2.5 0.8 4.1 33 7.41 30 19 26

4 0.8 4.7 49 4.61 40 12 35

6 0.8 5.4 69 3.08 51 7.9 45

10 1 7 116 1.83 71 4.7 63

16 1 8 175 1.15 95 2.9 85

25 1.2 10.1 274 0.727 126 1.9 111

35 1.2 11.3 367 0.524 156 1.35 138

50 1.4 13 495 0.387 189 1.05 168

70 1.4 15 699 0.268 240 0.75 214

95 1.6 17 968 0.193 290 0.58 259

120 1.6 19 1164 0.153 336 0.48 299

150 1.8 21 1413 0.124 375 0.43 328

185 2 23.5 1828 0.0991 426 0.37 370

240 2.2 26.5 2320 0.0754 500 0.33 433

300 2.4 29.5 2988 0.0601 573 0.31 493

400 2.6 34.3 3700 0.047 683 0.29 584

500 2.8 38.2 4750 0.0366 783 0.28 666630 2.8 42.5 6000 0.0283 900 0.27 764

Three or Fou

Cables, Thre

Phase a.c Cur

Rating

Maximum

conductor

Resistance at

20C

Nominal

Conductor Area

Radial Thickness

of Insuation

Mean Overall

Diameter (upper

limit)

Approximate

Cable WeightTwo cables,

Single phase a.c.

Current Rating

Two cables,

Single phase a.c.

Volt Drop per

Amp per Metre

Conductor AreaApproximate

Cable weight

Maximum armour

resistance at 20

C

Maximum

conductor

resistance at 20

C

Approximate Diameter

600 / 1000 V Copper Power Cables

Free A

Thre

Enclosed in conduit (method 30

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Single - core PVC insulated, non armoured, stranded copper conductors

( BS 6004 & BS 6346 )

Max. rating of'

2 x 1C, 1 Phase 3/4 x 1C, 3 Phase MCB / MCCB

mm mm (A)

1.5 1.5 10

2.5 2.5 154 4 20

6 6 25

6 10 30

10 16 40

16 25 50

25 35 60

35 50 80

- 70 100

- 95 125

- 120 150

Size of cables, in 'concealed' conduits

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Max. Load

current / demand

(A)

10

1520

25

30

40

50

60

80

100

125

150

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Edition 16 IEE wiring regulation

Current demand calculation

where: P = 1500 kw

V = 440 volt

P.F = 90%

I = amp

Fault Current Calculation

where: I = 2186.9 amp

t = 0.2 sec

k = 143

S = 6.8 mm

Applying diversity:

1st unit 100 % = 02nd unit 100 % = 0

3rd unit 25 % = 0

4th unit 25 % = 0

Total assumed Current demand = 0 amp

Loop Impedance calculation (Zs)

where: Zs = Loop impedance

Ze = External loop Impedance for distributor &services cables

R1 = Resistance of the phase conductor

R2 = Circuit protective conductor (Earth)

Zs = Ze + ( R1 + R2)

a u ate va ue o 1+ 2) x rcu t engt x u t p er

Correction Factors

where:

Ca = Factor for ambient temperature

Cg = Factor for groups of cables

Cf = Factor if BS 3036 rewirable fuse is used (factor is 0.725)

Ci = Factor if cable is sorrounded by thermally insulating materialIb = Design current

It = Tabulated conductor current carrying capacity

In = Nominal rating or setting of protection

Iz = Current carrying capacity of the conductors

I2 = Current causing operation of the device

2186.9

( R1 + R2) = 1000

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Ca x Cg x Cf x CiIt

In

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Short Circuit Current Calculation

Formula:

k x S t

Where:

I = Short circuit current (Amps)

S = Copper area of conductor (mm) 1.5

t = Duration of short circuit current (seconds) 0.5

up to 5 seconds maximum

k = Constant to allow for an initial temperature

of 90 C & final conductor temperature of 250 C

= 143

I = 303.35 Amps

Notes:

1

2 It shound be ensured that the accessories associated with the cables are also capable of

operation at these values of fault current and temperature.

The formula given is based on the cables being fullly loaded at the start of a short circuit

(conductor temperature 90 C) and a final conductor temperature of 250 C.

=I

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Power Factor improvement

at 90% power

factor

at 60% power

factor

1273.5 kvar 1500 kvar

1350 kvar

76.5 kvar