Telephone Cables

 Foam Skin Insulated & LAP Sheathed Jelly Filled Cables to RUS(REA) PE-89

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 where additional mechanical or rodent protection is required. A figure-8 self support option is offered for aerial installation.

Standards

• RUS(REA) PE-89 (RUS 7 CFR 1755.890)

Construction

Telephone Cables

Telephone Cables

Conductors
Solid annealed bare copper, 0.4/0.5/0.63/0.9mm as per ASTM B-3/class1 of IEC 60028

Insulation
Foam Skin which is a composite polyethylene insulation made of an inner cellular layer and an outer solid skin as per ASTM D 1248/IEC 60708

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

Cabling Element
Twisted Pairs

Cable Core Assembly
Cables of 25 pairs or less are assembled into cylindrical core. Cables larger than 25 pairs are assembled into units, which are then used to form the core Units are identified by colour coded binders. Standard construction is per RUS(REA) PE-89 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 corrugated copolymer coated aluminium tape (0.2mm/8mil) is applied directly over the cable core to provide 100% electrical shielding coverage and ensure a barrier against water vapor

Filling
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 ASTM D 1248/IEC 60708, being able to withstand exposure to sunlight,temperature variations, ground chemicals and other environmental contaminants

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

Spare Pairs (optional)
Spare pairs may be incorporated for large pair cables

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

Telephone Cables

Telephone Cables

Optional Construction

Armoured Cable
Corrugated copolymer coated steel tape armour (0.15mm/6mil) is applied with an overlap over an optional inner polyethylene sheath. 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

0.63

0.9

Conductor Gauge Size

AWG

26

24 22

19

Maximum Average DC Resistance

Ω/km / Ω/mile

140/225

87/140 55/88.6

27.0/43.4

Maximum Individual DC Resistance

Ω/km / Ω/mile

144.2/232

89.5/144 56.5/91.0

28.0/45.0

Minimum Insulation Resistance @500V DC

MΩ.km / MΩ.mile

1600/1000

1600/1000 1600/1000

1600/1000

Maximum Average Resistance Unbalance

%

1.5

1.5 1.5

1.5

Maximum Individual Resistance Unbalance

%

5

5 5

5

Average Mutual Capacitance

nF/km / nF/kft

48.5-54.0
/14.8-16.5

48.5-54.0
/14.8-16.5
48.5-54.0
/14.8-16.5

48.5-54.0
/14.8-16.5

Maximum Individual Mutual Capacitance

nF/km / nF/kft

57/17.4

57/17.4 57/17.4

57/17.4

Maximum Individual Capacitance Unbalance pair-to-pair

pF/km / pF/kft

145/44

145/44 145/44

145/44

Capacitance Unbalance RMS pair-to-pair

pF/km / pF/kft

45/13.7

45/13.7 45/13.7

45/13.7

Maximum Individual Capacitance Unbalance
pair-to-ground

pF/km / pF/kft

2625/800

2625/800 2625/800

2625/800

Maximum Average Capacitance Unbalance pair-to-ground

pF/km / pF/kft

574/175

574/175 574/175

574/175

Maximum Conductor Loop Resistance @20°C

Ω/km / Ω/mile

300/482

192/309 114/183.6

60/96.4

Impedance @1KHz

994

796 660

445

Impedance @100KHz

147

134 125

122

Impedance @512KHz

120

118 117

116

Impedance @1MHz

117

115 114

113

Maximum Average Attenuation @0.8KHz

dB/km / dB/kft

1.64/0.5

1.30/0.39 1.04/0.32

0.74/0.22

Maximum Average Attenuation @1KHz

dB/km / dB/kft

1.68/0.51

1.35/0.41 1.08/0.33

0.76/0.23

Maximum Average Attenuation @3KHz

dB/km / dB/kft

3.18/0.97

2.52/0.77 2.01/0.61

1.42/0.43

Maximum Average Attenuation @150KHz

dB/km / dB/kft

11.4/3.47

8.3/2.53 6.2/1.89

4.4/1.34

Maximum Average Attenuation @772KHz

dB/km / dB/kft

24.3/7.4

19.4/5.9 15.4/4.7

10.8/3.3

Maximum Average Attenuation @1000KHz

dB/km / dB/kft

27.1/8.25

21.4/6.52 17.5/5.33

12.8/3.89

Dielectric Strength

 

 

     

Conductor to Conductor (3secs)

V DC

2400

3000 4000

5000

Conductor to Screen (3secs)

V DC

10000

10000 10000

10000

Minimum EL Far-end Cross-talk-Mean Power Sum          

           @150KHz

dB/305m / dB/kft

61

63

63

65

           @772KHz

dB/305m / dB/kft

47

49

49

57

           @1.6MHz

dB/305m / dB/kft

41

42

43

44

           @3.15MHz

dB/305m / dB/kft

35

37

37

39

           @6.3MHz

dB/305m / dB/kft

29

31

31

33

Minimum Far-end Cross-talk-Worst Pair Power Sum          

           @150KHz

dB/305m / dB/kft

57

57

57

59

           @772KHz

dB/305m / dB/kft

43

43

43

45

           @1.6MHz

dB/305m / dB/kft

37

37

37

39

           @3.15MHz

dB/305m / dB/kft

31

31

31

33

           @6.3MHz

dB/305m / dB/kft

25

25

25

27

Minimum Near-end Cross-talk-Mean Power Sum          

           @150KHz

dB/305m / dB/kft

58

58

58

58

           @772KHz

dB/305m / dB/kft

47

47

47

47

           @1.6MHz

dB/305m / dB/kft

43

43

43

43

           @3.15MHz

dB/305m / dB/kft

38

38

38

38

           @6.3MHz

dB/305m / dB/kft

34

34

34

34

Minimum Near-end Cross-talk-Worst Pair Power Sum          

           @150KHz

dB/305m / dB/kft

53

53

53

53

           @772KHz

dB/305m / dB/kft

42

42

42

42

           @1.6MHz

dB/305m / dB/kft

38

38

38

38

           @3.15MHz

dB/305m / dB/kft

33

33

33

33

           @6.3MHz

dB/305m / dB/kft

29

29

29

29

Nominal Insulation Thickness

mm

0.175

0.2

0.26

0.3

Nominal Insulated Conductor Diameter

mm

0.75

0.9

1.15

1.5

1 2