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WELDING CABLES
 
 

CURRENT DERATING FACTORS FOR XLPE CABLES

RATING FACTORS FOR DEPTH OF LAYING FOR CABLES LAID DIRECT IN THE GROUND

Depth of Laying (mm)

900

1050

1200

1500

1800

2000

2500

3000 or more

1.1, 3.3, 6.6, 11, 22 & 33 KV Cables

1.00

0.99

0.97

0.95

0.94

0.93

0.91

0.90

RATING FACTORS FOR VARIATION IN GROUND TEMPERATURE FOR CABLES LAID DIRECT IN THE GROUND

Ground Temperature C

15

20

25

30

35

40

45

50

Rating Factor (maximum conductor temperature 90 C)

1.12

1.08

1.04

1.00

0.96

0.91

0.87

0.82


No. of

Circuits

Spacing between trefoil group centres (mm)

Touching

200

400

600

800

2

0.79

0.86

0.90

0.92

0.94

3

0.67

0.77

0.82

0.86

0.89

4

0.61

0.7

0.79

0.83

0.87

5

0.56

0.68

0.76

0.81

0.85

6

0.53

0.65

0.74

0.80

0.84

7

0.50

0.63

0.72

0.78

0.83

8

0.48

0.61

0.71

0.78

-

9

0.46

0.60

0.70

0.77

-

10

0.44

0.59

0.69

-

-

11

0.43

0.58

0.69

-

-

12

0.42

0.57

0.68

-

-

GROUP RATING FACTORS FOR CIRCUITS OF THREE SINGLE CORE CABLES IN TREFOIL, LAID DIRECT IN THE GROUND


GROUP RATING FACTORS FOR THREE CORE CABLES IN HORIZONTAL FORMATION, LAID DIRECT IN THE GROUND


No. of

Circuits

Spacing between trefoil group centres (mm)

Touching

200

400

600

800

2

0.76

0.83

0.87

0.90

0.92

3

0.64

0.72

0.79

0.83

0.86

4

0.58

0.67

0.75

0.80

0.84

5

0.53

0.63

0.71

0.77

0.81

6

0.50

0.60

0.69

0.76

0.80

7

0.47

0.58

0.67

0.74

0.79

8

0.45

0.56

0.66

0.73

-

9

0.43

0.55

0.65

0.73

-

10

0.42

0.54

0.64

-

-

11

0.41

0.53

0.64

-

-

12

0.40

0.52

0.63

-

-

RATING FACTORS FOR DEPTH OF LAYING SINGLE OR THREE CORE CABLES SINGLE-WAY DUCTS

Depth of Laying (mm)

900

1050

1200

1500

1800

2000

2500

3000 or more

1.1, 3.3, 6.6, 11, 22 & 33 KV Cables

1.00

0.99

0.98

0.96

0.95

0.94

0.93

0.92

RATING FACTORS FOR VARIATION IN GROUND TEMPERATURE FOR CABLES IN THE DUCTS

Ground Temperature C

15

20

25

30

35

40

45

50

Rating Factor (maximum conductor temperature 90 C)

1.12

1.08

1.04

1.00

0.96

0.91

0.87

0.82



 

Nominal area of conductor

Value of Thermal Resistivity of Soil C cm/w

Sq. mm

100

120

150

200

250

300

25

1.07

1.04

1.00

0.93

0.89

0.84

35

1.07

1.04

1.00

0.93

0.88

0.83

50

1.07

1.04

1.00

0.93

0.88

0.83

70

1.08

1.04

1.00

0.93

0.88

0.83

95

1.08

1.05

1.00

0.93

0.87

0.83

120

1.09

1.05

1.00

0.93

0.87

0.83

150

1.09

1.05

1.00

0.93

0.87

0.83

185

1.09

1.05

1.00

0.93

0.87

0.82

240

1.09

1.05

1.00

0.93

0.87

0.82

300

1.09

1.05

1.00

0.92

0.87

0.82

400

1.10

1.06

1.00

0.92

0.87

0.82

500

1.10

1.06

1.00

0.92

0.86

0.81

RATING FACTORS FOR VARIATION IN THERMAL RESISTIVITY OF SOIL FOR THREE SINGLE CORE CABLES IN DUCTS


RATING FACTORS FOR VARIATION IN THERMAL RESISTIVITY OF SOIL FOR THREE CORE CABLES IN SINGLE-WAY DUCTS


Nominal area of conductor

Value of Thermal Resistivity of Soil C cm/w

Sq. mm

100

120

150

200

250

300

25

1.11

1.05

1.00

0.92

0.85

0.80

35

1.11

1.06

1.00

0.92

0.85

0.80

50

1.12

1.06

1.00

0.92

0.85

0.79

70

1.12

1.06

1.00

0.92

0.85

0.79

95

1.12

1.07

1.00

0.91

0.84

0.79

120

1.12

1.07

1.00

0.91

0.84

0.79

150

1.12

1.07

1.00

0.91

0.84

0.78

185

1.13

1.07

1.00

0.91

0.84

0.78

240

1.13

1.07

1.00

0.90

0.83

0.78

300

1.13

1.07

1.00

0.90

0.83

0.77

400

1.14

1.08

1.00

0.90

0.83

0.77

500

1.14

1.08

1.00

0.90

0.83

0.77

630

1.14

1.08

1.00

0.90

0.82

0.76

800

1.15

1.08

1.00

0.90

0.82

0.76

1000

1.15

1.08

1.00

0.90

0.82

0.76





No. of cables in group

Spacing between trefoil group centres (mm) (Centre to Centre)

Touching

200

400

600

800

2

0.85

0.89

0.92

0.94

0.95

3

0.75

0.81

0.86

0.89

0.91

4

0.70

0.76

0.83

0.87

0.89

5

0.65

0.73

0.80

0.85

0.88

6

0.62

0.70

0.78

0.84

0.87

7

0.59

0.68

0.77

0.82

0.86

8

0.57

0.67

0.76

0.82

-

9

0.55

0.65

0.75

0.81

-

10

0.54

0.64

0.74

-

-

11

0.52

0.63

0.74

-

-

12

0.51

0.62

0.73

-

-

GROUP RATING FACTORS FOR CIRCUITS OF SINGLE CORE CABLES IN SINGLE WAY DUCTS IN TREFOIL


GROUP RATING FACTORS FOR THREE CORE CABLES IN SINGLE WAY DUCTS IN HORIZONTAL FORMATION


No. of cables in group

Spacing between trefoil group centres (mm) (Centre to Centre)

Touching

200

400

600

800

2

0.81

0.85

0.89

0.91

0.93

3

0.69

0.75

0.81

0.84

0.87

4

0.64

0.69

0.77

0.82

0.85

5

0.59

0.65

0.74

0.79

0.83

6

0.56

0.63

0.72

0.78

0.82

7

0.53

0.60

0.70

0.77

0.81

8

0.51

0.59

0.69

0.76

-

9

0.49

0.57

0.68

0.75

-

10

0.48

0.56

0.67

-

-

11

0.47

0.55

0.66

-

-

12

0.46

0.54

0.66

-

-

 
                
 
 

*60°C  &  85°C  Class  - The  maximum  conductor  temperature  attained  for  the  duty  cycles  specified  for  the  welding  cables.
*DC  : Duty  Cycle, GP  : General  Purpose Type, HOFR  :  Heat  Resistant, Oil  Resistant  , Fire  Retardant Type.

 
 
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