CS-R

60 Hz

Choice of electric cable by calculation

For dimensioning the phase cross section area for the submersible motor need the following information:

• V: Rated voltage (V)

• I: Motor current (A)

• L: Length of cable (km)

• cos φ: power factor

• Ambient temperature (°C)

The choice of the minimum cross section area of the phase conductor is determined by the rated motor current and the values reported in Table 1.

Table 1

Type of cable*

four-wires cable

four-wires cable

four-wires cable

four-wires cable

four-wires cable

four-wires cable

four-wires cable

four-wires cable

single-wire cable

single-wire cable

single-wire cable

single-wire cable

single-wire cable

single-wire cable

single-wire cable

Cable cross

section

mm2

1.5

2.5

4

6

10

16

25

35

50

70

95

120

150

185

240

Maximum cable current

1 Ader

A

1)

A

2)

18

24

32

41

57

76

96

119

167

216

264

308

356

409

485

2 Ader

A

3)

15

20

27

35

48

65

82

101

142

184

224

262

303

348

412

Resistance

R at 80°C

ohm/km

4)

15.1

9.08

5.63

3.73

2.27

1.43

0.91

0.65

0.473

0.328

0.236

0.188

0.153

0.123

0.094

Reactance

X at 60Hz

ohm/km

4)

0,170

0,157

0,145

0,138

0,124

0,118

0,116

0,113

0,145

0,139

0,142

0,136

0,134

0,131

0,132

1)

IEC 60364-5-52:2009 Tab.B52.4 / C

2)

IEC 60364-5-52:2009 Tab.B52.6

3)

1)x0,85 IEC 60364-5-52:2009 Tab.B52.17 ITEM2

4)

UNEL 35023-70

* Up to 35 mm

2

sections four-wire cable are used, from 50 mm

2

single core cables are recommended as well.Tab.1

The maximum current of the cables listed in Table 1 are for ambient temperature of 30 ° C.

When the temperature is different, the maximum current of the cables should be corrected by a factor given in Table 2.

The cross section area of the phase conductor is choosen by checking the voltage drop along the line , through the following equation:

DU% = 1,73*I*L*(R*cos φ+X*sen φ)/(V*1000)

DU% the voltage drop should not be greater than 3%

R, X = cable resistance and reactance in ohms/km (indicated in Table 1)

senφ = √ 1-(cosφ)2

In case of star / delta starting the rated current of the motor should be divided by 1.73.

Determination of minimal sections of the protective conductor PE.

Table 2 (IEC 60364-5-52:2009 Tab.B.52.14)

Ambient Temperature °C

Correction factor

10

1,22

15

1,17

20

1,12

25

1,06

30

1

35

0,94

40

0,87

45

0,79

50

0,71

55

0,61

60

0,5

Table 3 (CEI 64-8:2007 Tab.54F)

Phase cross section area

S

mm2

PE cross section area

SPE

mm2

S ≤ 16

S

16 < S ≤ 25

16

S > 25

S/2

399