Telephone Cables

 Foam Skin Insulated & LAP Sheathed Jelly Filled Cables to IEC60708

Application

The cables are designed for use in access or trunk networks, from telephone exchange to subscriber area. The cables are suitable for installation in ducts, direct burial in the ground and also for aerial installation with integral suspension strand.Jelly filled option is for subscriber’s cables installed underground or along the edge of pavement. An armoured option is offered for direct burial installations. A figure-8 self support option is offered for aerial installation.

Standards

• IEC 60708

Construction

Telephone Cables

Telephone Cables

Conductors
Solid annealed bare copper, 0.4/0.5/0.6/0.63/0.8/0.9 mm as per class 1 of IEC 60228 & ASTM B-3

Insulation
Foam Skin which is a composite polyethylene insulation made of an inner cellular layer and an outer solid skin, as per IEC 60708/BS EN 50290-2-23/BS 6234/ ASTM D 1248/NFC 32-060/VDE 0207

Twisted Pairs
Insulated conductors are twisted into pairs with varying lay length to minimize crosstalk

Cabling Element
Twisted Pairs

Cable Core Assembly
Cables with 100 pairs or less are composed of 10-pair sub-units; cables with over 100 pairs are composed of 50 or 100-pair units. Any extra pairs form a separate unit. Units are identified by colour coded binders. Standard construction is per IEC 60708 given in Cable Make Up Diagram

Core Wrapping
One or more non-hygroscopic polyester tapes are helically or longitudinally laid with an overlap. These tapes furnish thermal, mechanical as well as high dielectric protection between shielding and individual conductors

Moisture Barrier
A layer of aluminium tape (0.15mm) coated with PE-copolymer on one or both sides is applied longitudinally with overlap over the cable core to provide 100% electrical shielding coverage and ensure a barrier against water vapor. In cables with more than 200 pairs, the aluminum tape may be corrugated for improved cable flexibility

Filling (optional)
The cable core interstices are filled with petroleum jelly to avoid longitudinal water penetration within the cable. The water resistant filling compound is applied to the air space between non-hygroscopic tape and shield,shield and sheath within the cable core

Sheath
Black low density polyethylene as per BS 6234/IEC 60708/ASTM D 1248, being able to withstand exposure to sunlight, temperature variations, ground chemicals and other environmental contaminants

Ripcord
Ripcord may be provided for slitting the sheath longitudinally to facilitate its removal

Spare Pairs (optional)
Spare pairs may be incorporated for 200 and larger pair cables

Continuity Wire (optional)
One tinned copper drain wire may be longitudinally laid to ensure electrical continuity of the screen

Optional Construction

Armoured Cable
Steel wire armour or corrugated steel tape armour is applied over an optional inner polyethylene sheath. For steel tape version, the 0.2/0.5mm thick steel tape is coated with a copolymer and applied with an overlap. An outer polyethylene sheath is applied over the armour

Self-Support Cables
A 7-strand galvanized steel strand is used as support wire. Black polyethylene sheath covers both core and support wire in a figure-8 construction

Electrical Properties

Nominal Conductor Diameter

mm

0.4

0.5

0.6

0.63

0.8

0.9

Conductor Gauge Size

AWG

26

24

-

22

20

19

Conductor Size

mm2

0.126

0.196

0.283

0.312

0.5

0.636

Maximum Average Conductor Resistance @20°C

Ω/km

143

91

63

58

34.6

28

Minimum Insulation Resistance @500V DC

MΩ.km

5000

5000

5000

5000

5000

5000

Maximum Average Mutual Capacitance @800Hz

nF/km

53

53

56

56

59

59

Maximum Individual Mutual Capacitance @800Hz
(for 99% cases)

nF/km

60

60

60

60

64

64

Maximum Individual Capacitance Unbalance
@800Hz pair-to-pair

pF/500m

250

250

250

250

160

160

Maximum Individual Capacitance Unbalance
@800Hz pair-to-pair ( for 95% cases)

pF/500m

150

150

150

150

100

100

Maximum Individual Capacitance Unbalance
@800Hz pair-to-ground

pF/500m

1700

1700

1700

1700

1700

1700

Maximum Individual Capacitance Unbalance
@800Hz pair-to-ground ( for 95% cases)

pF/500m

1000

1000

1000

1000

1000

1000

Maximum Conductor Loop Resistance @20°C

Ω/km

300

192

130

114

73

60

Impedance @1KHz

994

796

665

660

500

445

Impedance @100KHz

147

134

127

125

124

122

Impedance @512KHz

120

118

117.5

117

116.5

116

Impedance @1MHz

117

115

114.5

114

113.5

113

Maximum Average Attenuation @0.8KHz

dB/km

1.64

1.30

1.1

1.04

0.9

0.74

Maximum Average Attenuation @1KHz

dB/km

1.68

1.35

1.14

1.08

0.93

0.76

Maximum Average Attenuation @3KHz

dB/km

3.18

2.52

2.3

2.01

1.74

1.42

Maximum Average Attenuation @150KHz

dB/km

11.4

8.3

7.2

6.2

5.7

4.4

Maximum Average Attenuation @772KHz

dB/km

24.3

19.4

17.4

15.4

13.1

10.8

Maximum Average Attenuation @1000KHz

dB/km

27.1

21.4

18.5

17.5

13.7

12.8

Dielectric Strength              

       Conductor to Conductor (1min)

V DC

500

500

500

500

500

500

       Conductor to Screen (1min)

V DC

1000

1000

1000

1000

1000

1000

Nominal Insulation Thickness

mm

0.175

0.20

0.25

0.26

0.3

0.3

Nominal Insulated Conductor Diameter

mm

0.75

0.90

1.1

1.15

1.4

1.5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Mechanical and Thermal Properties

Temperature range during operation (fixed state): -30°C – +70°C
Temperature range during installation (mobile state): -20°C – +50°C
Minimum bending radius: 10 x Overall Diameter (unarmoured cables);15 x Overall Diameter (armoured cables)

Colour Code
Standard colour code is per IEC 60708 given in Colour Code Chart

Dimensions And Weight
Foam Skin Insulated and LAP Sheathed Jelly Filled Cable to IEC 60708

Cable Code Number of Pairs Nominal Sheath
Thickness
mm
Nominal Overall
Diameter
mm
Nominal Weight
kg/km
0.4mm Conductor, 0.75mm Insulated Wire

TP708-02YSF(L)2Y-10P04

10

1.5

9.0

82

TP708-02YSF(L)2Y-20P04

20

1.5

10.0

120

TP708-02YSF(L)2Y-30P04

30

1.5

11.0

161

TP708-02YSF(L)2Y-50P04

50

1.5

14.0

239

TP708-02YSF(L)2Y-70P04

70

1.5

15.0

315

TP708-02YSF(L)2Y-100P04

100

1.5

18.0

434

TP708-02YSF(L)2Y-150P04

150

1.5

21.0

630

TP708-02YSF(L)2Y-200P04

200

1.8

24.0

824

TP708-02YSF(L)2Y-300P04

300

1.8

29.0

1195

TP708-02YSF(L)2Y-400P04

400

1.8

32.0

1556

TP708-02YSF(L)2Y-500P04

500

2.0

36.0

1921

TP708-02YSF(L)2Y-600P04

600

2.0

39.0

2282

TP708-02YSF(L)2Y-800P04

800

2.5

44.0

2987

TP708-02YSF(L)2Y-900P04

900

2.5

46.0

3364

TP708-02YSF(L)2Y-1000P04

1000

2.5

49.0

3712

TP708-02YSF(L)2Y-1200P04

1200

2.8

53.0

4411

TP708-02YSF(L)2Y-1500P04

1500

2.8

59.0

5483

TP708-02YSF(L)2Y-1800P04

1800

3.2

64.0

6567

TP708-02YSF(L)2Y-2100P04

2100

3.2

69.0

7626

TP708-02YSF(L)2Y-2400P04

2400

3.5

73.0

8663

TP708-02YSF(L)2Y-2700P04

2700

3.5

77.0

9697

TP708-02YSF(L)2Y-3000P04

3000

3.5

81.0

10729

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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